201101526 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種光二極體之製造方法及光二極體。 【先前技術】 . 作為於近紅外光之波長帶域具有較高之光譜靈敏度特性 之光二極體，已知有使用化合物半導體之光二極體（例如 參照專利文獻1)。專利文獻1中所記載之光二極體包括： 第 光層’其包含InGaAsN、InGaAsNSb 及 InGaAsNP 之 Ο 任一者；及第2受光層，其具有波長較第1受光層之吸收端 更長之吸收端，且包含量子井構造。 先行技術文獻 專利文獻 專利文獻1:日本專利特開2008-153311號公報 【發明内容】 發明所欲解決之問題 然而’此種使用化合物半導體之光二極體仍為高價，製 造步驟亦複雜。因此，需要一種矽光二極體之實用化該 石夕光二極體廉價且容易製造，並且於近紅外光之波長帶域 具有充分之光譜靈敏度。通常，矽光二極體於光譜靈敏度 特性之長波長側之極限為11 〇〇 nm左右，但於1 〇〇〇 nm以上 之波長帶域中之光譜靈敏度特性並不充分。 本發明之目的在於提供一種光二極體之製造方法及光二 極體，該光一極體係石夕光二極體，且於近紅外光之波長帶 域具有充分之光譜靈敏度特性。 146657.doc 201101526 解決問題之技術手段 本發明之光二極體之製造方法包括以下步驟：準備矽基 板，該矽基板包含第丨導電型之半導體，具有相互對向之 第1主面及第2主面，並且於第！主面侧形成有第2導電型之 半導體區域；對矽基板之第2主面中之至少與第2導電型之 半導體區域對向之區域照射脈衝雷射光，而形成不規則之 凹凸；於形成不規則之凹凸之步驟之後，於矽基板之第2 主面側形成具有較矽基板更高之雜質濃度之第丨導電型之 累積層；及於形成第1導電型之累積層之步驟之後，對矽 基板進行熱處理。 根據本發明之光二極體之製造方法，可獲得於矽基板之 第2主面中之至少與第2導電型之半導體區域對向的區域形 成有不規則之凹凸之光二極體。該光二極體中，因於第二 主面中之至少與第2導電型之半導體區域對向之區域形成 有不規則之凹凸，故入射至光二極體之光由該區域反射、 散射或擴散，而於矽基板内行進較長之距離。藉此，入射 至光二極體之光之大部分由矽基板吸收，而不會穿透光二 極體（石夕基板）。因此，上述光二極體中，人射至光二極體 之光之行進距離變長，吸收光之距離亦變長，因此於近紅 外光之波長帶域之光譜靈敏度特性提高。 由本發明所獲得之光二極體中，於石夕基板之第2主㈣ 形成有具有較矽基板更高之雜質濃度之幻導電型之累券 層。因此，於第2主面側不藉由氺而弇 稽田先而產生之多餘載子進;^ 再結合，可減少暗電流。第1導雷 矛导電型之上述累積層係抑帝 146657.doc 201101526 於石夕基板之第2主面附近藉由光而產生之載子由該第2主面 捕獲。因&’藉由光而產生之載子有效地朝向第2導電型 之半導體區域與矽基板之pn接合部移動，從而可提高光 極體之光檢測靈敏度。 另外，由於脈衝雷射光之照射，可 ·Γ 對矽基板造成結晶201101526 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to a method of manufacturing a photodiode and a photodiode. [Prior Art] As a photodiode having a high spectral sensitivity characteristic in the wavelength band of the near-infrared light, a photodiode using a compound semiconductor is known (for example, refer to Patent Document 1). The photodiode described in Patent Document 1 includes: a first light layer ′ including any one of InGaAsN, InGaAsNSb, and InGaAsNP; and a second light receiving layer having a longer absorption wavelength than an absorption end of the first light receiving layer End, and contains quantum well construction. [Problem to be Solved by the Invention] However, the photodiode using the compound semiconductor is still expensive and the manufacturing steps are complicated. Therefore, there is a need for a practical application of a light-emitting diode which is inexpensive and easy to manufacture, and has sufficient spectral sensitivity in the wavelength band of near-infrared light. Generally, the limit of the long-wavelength side of the spectral sensitivity characteristic of the phosphor diode is about 11 〇〇 nm, but the spectral sensitivity characteristics in the wavelength band of 1 〇〇〇 nm or more are not sufficient. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a photodiode and a photodiode having a spectral sensitivity characteristic in a wavelength region of near-infrared light. 146657.doc 201101526 Technical Solution to Problem The method for manufacturing a photodiode according to the present invention includes the steps of: preparing a germanium substrate comprising a semiconductor of a second conductivity type, having a first main surface and a second main surface facing each other Face, and in the first! A semiconductor region of a second conductivity type is formed on the main surface side; and at least a region of the second main surface of the substrate opposite to the semiconductor region of the second conductivity type is irradiated with pulsed laser light to form irregular irregularities; After the step of irregular concavity, a second conductivity type accumulation layer having a higher impurity concentration than the tantalum substrate is formed on the second main surface side of the tantalum substrate; and after the step of forming the accumulation layer of the first conductivity type, The tantalum substrate is heat treated. According to the method of producing a photodiode of the present invention, it is possible to form a photodiode having irregular irregularities in at least a region of the second main surface of the tantalum substrate facing the semiconductor region of the second conductivity type. In the photodiode, irregular irregularities are formed in at least a region of the second main surface opposite to the semiconductor region of the second conductivity type, so that light incident on the photodiode is reflected, scattered, or diffused by the region. And travel a long distance inside the substrate. Thereby, most of the light incident on the photodiode is absorbed by the germanium substrate without penetrating the photodiode (the stone substrate). Therefore, in the above-described photodiode, the traveling distance of the light which is incident on the photodiode is long, and the distance of the absorbed light is also long, so that the spectral sensitivity characteristic in the wavelength band of the near-infrared light is improved. In the photodiode obtained by the present invention, a second conductive layer of a meta-conductivity type having a higher impurity concentration than that of the tantalum substrate is formed on the second main (four) of the Shixi substrate. Therefore, on the second main surface side, the excess carriers generated by 稽 先 先 先 先 先 先 先 ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ The above-mentioned accumulation layer of the first guide thief-conducting type is 146657.doc 201101526 The carrier generated by the light near the second main surface of the Shishixi substrate is captured by the second main surface. Since the carrier generated by the light is efficiently moved toward the pn junction portion of the second conductivity type semiconductor region and the germanium substrate, the light detection sensitivity of the photoelectrode can be improved. In addition, due to the irradiation of pulsed laser light, it can cause crystallization of the substrate.
GG
缺陷等之損害。然@，本發明中，於形成第i導電型之累 積層之步驟之後，料基板進行熱處理，因切基板之結 晶性恢復，從而可防止暗電流之增加等不良。 較佳為ϋ包括如下步驟：於形成不規狀凹凸之步 驟之前，將發基板中之與第2導電型之半導體區域對應之 部分自第2主面側起薄化，而殘留該部分之周邊部分。於 該情形_，可獲得分別將碎基板之第i主面及第2主面側作 為光入射面之光二極體。 本發明之光一極體之製造方法包括以下步驟：準備矽基 板，該矽基板包含第1導電型之半導體，具有相互對向之 第1主面及第2主面，並且於第}主面側形成有第2導電型之 半導體區域；於矽基板之第2主面侧形成具有較矽基板更 高之雜質濃度之第1導電型之累積層；於形成第丨導電型之 累積層之步驟之後，對石夕基板之第2主面中之至少與第2導 電型之半導體區域對向之區域照射脈衝雷射光，而形成不 規則之凹凸；及於形成不規則之凹凸之步驟之後，對矽基 板進行熱處理。 本發明之光二極體之製造方法中，如上所述，入射至光 二極體之光之行進距離變長，吸收光之距離亦變長，因此 146657.doc 201101526 於近紅外光之波長帶域之光譜靈敏度特性提高。藉由形成 於石夕基板之第2主面側之第1電型之累積層，可減少暗電 流，並且可提高光二極體之光檢測靈敏度。本發明中，於 形成不規則之凹凸之步驟之後，對矽基板進行熱處理，因 此矽基板之結晶性恢復，可防止暗電流之增加等不良。 較佳為，進而包括如下步驟·_於形成第丨導電型之累積 層之步驟之前’將石夕基板中之與第2導電型之半導體區域 對應之部分自第2主面侧起薄化，而殘留該部分之周邊部 分。於該情形時，可獲得分別將矽基板之第丨主面及第二主 面側作為光入射面之光二極體。 較2為’使帛1導電型之累積層之厚度大於不規則之凹 凸之高低差。於該情形時，即便於形成第〗導電型之累積 層之步驟之後，照射脈衝雷射光而形成不規則之上述凹 凸’累積層仍殘留。因此，可確保上述累積層之作用效 果。 較佳為，於準備矽基板之步驟中，作為矽基板，準備於 第1主面側進而形成具有較矽基板更高之雜質濃度之第1導 電型之半導體區域的矽基板’且進而包括如下步驟：於對 矽基板進行熱處理之步驟之後，形成與第i導電型之半導 體區域電性連接之電極、及與第2導電型之半導體區域電 性連接之電極。於該情形時，即便於電極使用溶點相對較 低之金屬t情形_，電㉟亦不會由於熱處理之步驟而熔 融。因此，可不受熱處理之影響而適當地形成電極。 較佳為，於形成不規則之上述凹凸之步驟中，照射皮秒 146657.doc 201101526 〜飛秒脈衝雷射光作為脈衝雷射光。於該情形時， 且容易地形成不規則之凹凸。 * 本發明之光二極體包括矽基板，該矽基板包含第^導電 型之半導體，具有相互對向之第i主面及第2主面，並且於 第1主面側形成有第2導電型之半導體區域，於矽基板之第 2主面側形成有具有較矽基板更高之雜質濃度之第i導電型 之累積層，並且於第2主面中之至少與第2導電型之半導體 ❹ 區域對向之區域形成有不規則之凹凸，矽基板之第2主面 中之”第2導電型之半導體區域對向之區域係光學性地露 出0 本發明之光二極體中，如上所述，入射至光二極體之光 之行進距離變長，吸收光之距離亦變長，因此於近紅外光 之波長帶域之光譜靈敏度特性提高。藉由形成於矽基板之 第2主面側之第丨導電型之累積層，可減少暗電流，並且可 提高光二極體之光檢測靈敏度。 較佳為，將矽基板之與第2導電型之半導體區域對應之 部分自第2主面側起薄化，而殘留該部分之周邊部分。於 該情形時，可獲得分別將矽基板之第1主面及第2主面側作 為光入射面之光二極體。 較佳為，第1導電型之累積層之厚度大於不規則之上述 凹凸之高低差。於該情形時，如上所述，可確保累積層之 作用效果。 較佳為’矽基板包括：第丨半導體基板，其包含第1導電 型之半導體；及第2半導體基板，其貼附於第〗半導體基板 146657.doc 201101526 上，包含第】導電型之半導體，並且具有較第】半導體基板 更高之雜質濃度，·於第】半導體基板之與和第2半導體基板 之貼附面對向之面側形成有第2導電型之半導體區域，於 第2半導體基板之與和第丨半導體基板之貼附面對向之面中 的至> 與第2導電型之半導體區域對向之區域，形成有不 規則之凹凸。於該情形時，可實現於近紅外光之波長帶域 之光譜靈敏度特性已提高之PIN光二極體。 較佳為，矽基板包括：第丨半導體基板，其包含第丨導電 型之半導體，及第2半導體基板，其貼附於第丨半導體基板 上，包含第1導電型之半導體，並且具有較第丨半導體基板 更同之雜質》辰度，於第丨半導體基板之與和第2半導體基板 之貼附面對向之面側形成有第2導電型之半導體區域，第i 半導體基板之貼附面中之至少與第2導電型之半導體區域 對向的區域露出且形成有不規則之凹凸。於該情形時，可 實現於近紅外光之波長帶域<光譜靈敏度特性已提高之 PIN光二極體。 較佳為，第1半導體基板之面方位為（111)，第2半導體基 板之面方位為（1〇0)。於該情形時，可使用貼合晶圓作為矽 基板（第1及第2半導體基板卜利用面方位之蝕刻速率之不 同，可精度良好地獲得均勻厚度之第丨半導體基板。因第丄 半導體基板與第2半導體基板之邊界面作為蝕刻終止層來 發揮功能，故蝕刻步驟中之作業性優異。 發明之效果 本發明，可提供一種光二極體之製造方法及光二極 146657.doc 201101526 體，該光二極體係梦光二極體，且於近紅外光之波長帶域 具有充分之光譜靈敏度特性。 【實施方式】 以下，參照隨附圖<，對本發明之較佳實施形態加以詳 說明。再者’於說明中’對於相同要素或具有相同功能 •之要素使用相同符號，省略重複之說明。 (第1實施形態） 參照圖1〜圖10,對第1實施形態之光二極體之製造方法 ° 加以說明。圖1〜圖10係用以對第1實施形態之光二極體之 製造方法進行說明之圖。 首先，準備包含矽（Si)結晶、且具有相互對向之第丨主面 la及第2主面lb之η型半導體基板丨（參照圖丨）。&型半導體 基板1之厚度為300 μιη左右，比電阻為i kn.cm左右。本實 施形1態巾，所謂「高雜質濃度」，例如係指雜質濃度為 1 xio17 cm·3左右以上，且係對導電型附加「+」來表示。 Q 所§胃「低雜質濃度」，例如係指雜質濃度為lxl〇15 左 右以下，且係對‘導電型附加「_」來表示。作為η型雜質存 在銻（Sb)、砷（As)或磷（Ρ)等，作為ρ型雜質存在硼（Β)等。 . 其次，於1^型半導體基板1之第1主面la侧形成ρ+型半導 . 體區域3及η型半導體區域5(參照圖2)。p+型半導體區域3 係藉由使用t央部開口之掩模等，使高濃度之ρ型雜質於 型半導體基板1内自第丨主面la側擴散而形成^ n+型半導 體區域5係藉由使用周邊部區域開口之其他掩模等，以包 圍P+型半導體區域3之方式，使較n-型半導體基板丨更高濃 146657.doc 201101526 度之n型雜質於n_型半導體基板1内自第1主面la侧擴散而形 成。P+型半導體區域3之厚度例如為〇55 μιη左右，薄片電 阻例如為44 Ω/sq.。η+型半導體區域5之厚度例如為15 μιη 左右’薄片電阻例如為12 Ω/sq.。 繼而於η型半導體基板1之第1主面1 a側形成絕緣層 7(參照圖3)。絕緣層7包含Si〇2 ,且係藉由將n_型半導體基 板1熱氧化而形成。絕緣層7之厚度例如為0丨μιη左右。之 後’於ρ型半導體區域3上之絕緣層7中形成接觸孔hi，於 η+型半導體區域5上之絕緣層7中形成接觸孔Η2。亦可形成 包含SiN之抗反射（ar，anti_reflective)層來代替絕緣層7。 人’於π型半導體基板1之第2主面ib上及絕緣層7上 形成鈍化層9(參照圖4)〇鈍化層9包含SiN ,且係藉由例如 電漿CVD(chemical vapor deposition,化學氣相沈積）法而 开> 成。純化層9之厚度例如為〇. 1 。繼而，自第2主面1 b 側對η型半導體基板1進行研磨，以使η·型半導體基板i之 厚度成為所需厚度（參照圖5)。藉此，將形成於η·型半導體 基板1之第2主面lb上之鈍化層9除去，而η·型半導體基板j 露出。此處，亦將藉由研磨而露出之表面作為第2主面 lb °所需厚度例如為27〇 μιη。 繼而，對η型半導體基板丨之第2主面丨b照射脈衝雷射光 PL ’而形成不規則之凹凸1〇(參照圖6)。此處，如圖7所 示’將η型半導體基板1配置於腔室c内，自配置於腔室c 之外側之脈衝雷射產生裝置PLD對η—型半導體基板工照射脈 衝雷射光PL。腔室C包括氣體導入部gin及氣體排出部 146657.doc -10- 201101526 G0UT ’將惰性氣體（例如氮氣或氬氣等）自氣體導入部Gw導 入後自氣體排出部G〇UT排出，藉此於腔室C内形成有惰性 氣體流Gf。藉由惰性氣體流Gf，將照射脈衝雷射光PL時所 產生之塵埃等排出至腔室C外，而防止加工屑或塵埃等附 •著於ιΓ型半導體基板1上。 本實施形態中’使用皮秒〜飛秒脈衝雷射產生裝置作為 脈衝雷射產生裝置PLD，且遍及第2主面lb之整個表面而 照射皮秒〜飛秒脈衝雷射光。第2主面lb受到皮秒〜飛秒脈 © 衝雷射光破壞’而如圖8所示，於第2主面lb之整個表面形 成不規則之凹凸10。不規則之凹凸1〇具有相對於與第又主 面la正交之方向而交又之表面。凹凸1〇之高低差例如為 0.5〜10 μιη左右，凹凸1〇中之凸部之間隔為〇5〜1〇 μηι左 右。皮秒〜飛秒脈衝雷射光之脈衝時間寬度（time width)例 如為50 fs〜2 ps左右，強度例如為4〜16 GW左右’脈衝能量 例如為200〜800 pj/pulse左右。更通常的是，峰值強度為 3xl〇U〜2.5xl013(W/Cm2) ’ 通量為on 3(J/cm2)左右。圖8 係觀察形成於第2主面lb上之不規則之凹凸1〇之 SEM(scanmng electron microscope，掃描式電子顯微鏡）圖 像。 其次，於n_型半導體基板1之第2主面lb側形成累積層 11(參照圖9)。此處，以成為較n-型半導體基板丨更高之雜 質濃度之方式，將η型雜質於n-型半導體基板i内自第2主 面1 b側離子植入或擴散，精此形成累積層1丨。累積層〗^之 厚度例如為1 μπι左右。 146657.doc 201101526 繼而’對n-型半導體基板1進行熱處理（退火）。此處，於 N2氣體之環境下以800〜丨000°c左右之範圍，將η·型半導體 基板1加熱0.5〜1小時左右。 其次’將形成於絕緣層7上之鈍化層9除去後，形成電極 13、15(參照圖10)。電極13形成於接觸孔出内，電極15形 成於接觸孔H2内。電極13、15分別包含紹（Ai)等，且厚度 例如為1 μηι左右。藉此’完成光二極體PD1。 如圖10所示，光二極體PD1包括n-型半導體基板i。於η· 型半導體基板1之第1主面la側形成有p+型半導體區域3及^ 型半導體區域5’於η型半導體基板1與p+型半導體區域3之 間形成有pn接合。電極13通過接觸孔H1而與p+型半導體區 域3電性接觸且連接。電極15通過接觸孔H2而與n+型半導 體區域5電性接觸且連接。 於η·型半導體基板1之第2主面lb形成有不規則之凹凸 10。於η型半導體基板1之第2主面ib側形成有累積層u， 且第2主面lb係光學性地露出。所謂第2主面lb光學性地露 出，不僅指第2主面lb與空氣等環境氣體接觸，而且亦包 括於第2主面lb上形成有光學上透明之臈之情形。 光一極體PD1中，於第2主面lb形成有不規則之凹凸 10。因此，如圖11所示，入射至光二極體pm之光[由凹 凸10反射、散射或擴散，而於n-型半導體基板丨内行進較 長之距離。 通常，相對於Si之折射率n=3 5 ’而空氣之折射率 n = 1.0。光二極體中，於光自與光入射面垂直之方向入射 146657.doc 12· 201101526 之情形時，未於光二極體（矽基板）内被吸收之光分為由光 入射面之背面反射之光成分、與穿透光二極體之光成分。 穿透光二極體之光不利於光二極體之靈敏度β由光入射面 之背面反射之光成分若在光二極體内被吸收，則成為光電 流。未被吸收之光成分係於光入射面，與到達光入射面之 背面之光成分同樣地反射或穿透。 光二極體PD1中，於光L自與光入射面（第1主面ia)垂直 之方向入射之情形時，若到達形成於第2主面ib之不規則 之凹凸10,則以與來自凹凸丨〇之出射方向成166。以上之角 度到達之光成分係由凹凸1 〇全反射。因凹凸丨〇不規則地形 成’故相對於出射方向具有各種角度，全反射之光成分朝 各個方向擴散。因此，全反射之光成分中存在由n-型半導 體基板1内部吸收之光成分，且存在到達第丨主面丨a及侧面 之光成分。 會到達第1主面la及側面之光成分由於凹凸1〇上之擴散 而朝各個方向行進。因此，到達第i主面la及側面之光成 分由第1主面la及側面全反射之可能性極高。由第i主面u 及侧面全反射之光成分反覆進行於不同表面之全反射，其 行進距離變得更長。入射至光二極體PDl之光•型半導 體基板1之内部行進較長之距離之期間，由n•型半導體基 板1吸收，而檢測為光電流。 入射至光一極體PD1之光L之大部分不會穿透光二極體 PD1，而疋仃進距離變長，由型半導體基板i吸收。因 此’光二極體PD1中’於近紅外光之波長帶域之光譜靈敏 146657.doc •13· 201101526 度特性提高。 當於第2主面lb形成有規則之凹凸之情形時，會到達第^ 主面la及側面之光成分雖由凹凸擴散，但朝相同方向行 進°因此’到達第1主面丨a及側面之光成分由第1主面丨&及 側面全反射之可能性較低。因此，於第丨主面1&及側面、 進而於第2主面ib中穿透之光成分增加，入射至光二極體 之光之行進距離較短。其結果為，難以提高於近紅外光之 波長帶域之光譜靈敏度特性。 此處，為了對第丨實施形態之於近紅外光之波長帶域之 光譜靈敏度特性之提高效果進行確認，而進行實驗。 製作包括上述構成之光二極體（稱作實施例〇、與未於 型半導體基板之第2主面形成不規則之凹凸之光二極體（稱 作比較例1)，研究各光譜靈敏度特性。實施例丨與比較例丄 除藉由脈衝雷射光之照射而形成不規則之凹凸方面以外， 為相同構成。將η·型半導體基板丨之尺寸設定為65 mmx6 5 mm。將p+型半導體區域3即光感應區域之尺寸設定為$ 8 mmx5.8 mm。將對光二極體施加之偏壓電壓VR設定為〇 V。 將結果示於圖12中。於圖12中，實施例丨之光譜靈敏度 特性係由T1所表示，比較例丨之光譜靈敏度特性係由特性 T2所表示。於圖12中，縱軸表示光譜靈敏度（mA/w)，橫 軸表示光之波長（nm)。以—點劃線所表示之特性表示量子 效率（QE，quantum efficiency)為1〇〇%之光譜靈敏度特性， 以虛線所表不之特性表示量子效率為5〇%之光譜靈敏度特 146657.doc • 14_ 201101526 性。 根據圖12可知，例如於1 ο" nm下，比較例1中光譜靈敏 度為0.2 A/W(QE=25%) ’相對於此而實施例1中光譜靈敏度 為0.6 A/W(QE=72%)，於近紅外光之波長帶域之光譜靈敏 度大幅提南。 亦對實施例1及比較例1中之光譜靈敏度之溫度特性進行 了確認。此處’使環境溫度自25°c上升至6(rc而研究光譜 靈敏度特性，求出60。(：下之光譜靈敏度相對於25°c下之光 β靈敏度之比例（溫度係數）。將結果示於圖1 3中。於圖1 3 中，實施例1之溫度係數之特性係由Τ3所表示，比較例1之 溫度係數之特性係由特性Τ4所表示。於圖13中，縱轴表示 溫度係數（％广C )，橫軸表示光之波長（nm)。 根據圖13可知，例如於1064 nmT，比較例！中溫度係數 為0.7%/°C，相對於此而實施例1中溫度係數為〇 2%/(>c， 溫度依存性較低。通常，若溫度上升，則吸收係數增大且 帶隙能量減少’藉此光譜靈敏度變高。實施例1中，於室 溫之狀態下光譜靈敏度亦充分高’因此與比較例1相比 較’溫度上升所引起之光譜靈敏度之變化變小。 光二極體PD1中，於η·型半導體基板i之第2主面lb側形 成有累積層11。藉此，於第2主面lb側不藉由光而產生之 多餘載子進行再結合，可減少暗電流。累積層丨丨係抑制於 第2主面lb附近藉由光而產生之載子由該第2主面lb捕獲。 因此’藉由光而產生之載子有效地朝向pn接合部移動，從 而可進一步提高光二極體PD1之光檢測靈敏度。 146657.doc •15· 201101526 第1實施形態中’於形成累積層11之後，對η-型半導體 基板1進行熱處理。藉此，η-型半導體基板1之結晶性恢 復’可防止暗電流之增加等不良。 第1實施形態中，於對η·型半導體基板丨進行熱處理後， 形成電極13、15。藉此’於電極13、15使用熔點相對較低 之金屬之情形時，電極丨3、I5亦不會由於熱處理而熔融。 因此，可不受熱處理之影響而適當地形成電極13、15。 第1實施形態中’照射皮秒〜飛秒脈衝雷射光，而形成不 規則之凹凸10。藉此’可適當且容易地形成不規則之凹凸 10 ° (第2實施形態） 參照圖14〜圖16，對第2實施形態之光二極體之製造方法 進行說明。圖14〜圖16係用以對第2實施形態之光二極體之 製造方法進行說明之圖。 第2實施形態之製造方法中，直至自第2主面沁側對n-型 半導體基板1進行研磨為止，與第丨實施形態之製造方法相 同，而省略至此為止之步驟之說明。自第2主面lb側對 型半導體基板1進行研磨，使n-型半導體基板丨成為所需厚 度之後’於η·型半導體基板丨之第2主面lb側形成累積層 11(參照圖14)。累積層11之形成係與第J實施形態同樣地進 行。累積層11之厚度例如為1 μιη左右。 其次，對η_型半導體基板1之第2主面115照射脈衝雷射光 PL ’而形成不規則之凹凸10(參照圖15)。不規則之凹凸 之形成係與第1實施形態同樣地進行。 146657.doc -16- 201101526 繼而’與第1實施形態同樣地對n-型半導體基板1進行熱 處理。之後，於將形成於絕緣層7上之鈍化層9除去之後， 形成電極13、15(參照圖16)。藉此，完成光二極體PD2。 於第2實施形態中’亦與第1實施形態同樣地，入射至光 二極體PD2之光之行進距離變長，吸收光之距離亦變長。 藉此，光二極體PD2中，亦可提高於近紅外光之波長帶域 之光譜靈敏度特性。 第2實施形態中，累積層丨丨之厚度大於不規則之凹凸j 〇 〇 之高低差。因此，即便於形成累積層11之後，照射脈衝雷 射光而形成不規則之凹凸10，累積層u仍確實地殘留。因 此’可確保累積層11之作用效果。 (第3實施形態） 參照圖17〜圖21，對第3實施形態之光二極體之製造方法 進仃說明。圖17〜圖21係用以對第3實施形態之光二極體之 製造方法進行說明之圖。 Q 第3實施形態之製造方法中，直至形成鈍化層9為止，與 第1實施形態之製造方法相同，而省略至此為止之步驟^ 說明。於形成鈍化層9之後，將n-型半導體基板丨中之與〆 料導體區域3對應之部分自第2主面⑻則起薄化，而殘留 胃部分之周邊部分(參照圖17)。n•型半導體基板以薄化例 如係藉由使用氫氧化鉀溶液或TMAH(tetramethyi hydroxide，氫氧化四甲基銨溶液）等之驗性餘 各向異性蝕刻而進行。n-型半導體基板丨之已薄化之 郤刀之厚度例如為1〇〇，左右，周邊部分之厚度例如為 I46657.doc 17· 201101526 300 μιη左右。 1進行研磨，以 所需厚度（參照 其次，自第2主面lb側對η-型半導體基板 使η·型半導體基板1之周邊部分之厚度成為 圖1 8)。所需厚度例如為270 μιη。 1 b照射脈衝雷射光 。不規則之凹凸1 〇 繼而，對η·型半導體基板1之第2主面 PL，而形成不規則之凹凸1 〇(參照圖i9) 之形成係與第1實施形態同樣地進行。 繼而，於η'型半導體基板！之已薄化之部分之第2主面卟 側形成累積層11(參照圖20)。累積層U之形成係與第丄實施 形態同樣地進行。累積層11之厚度例如為3 μιη左右。 其次，與第1實施形態同樣地，於對η-型半導體基板1進 行熱處理之後，將形成於絕緣層7上之鈍化層9除去，形成 電極13、15(參照圖21)。藉此，完成光二極體pd3。 於第3實施形態中，亦與第丨及第2實施形態同樣地入 射至光一極體PD3之光之行進距離變長，吸收光之距離亦 變長。藉此，光二極體PD3中，亦可提高於近紅外光之波 長帶域之光譜靈敏度特性。 第3實施形態中，於形成不規則之凹凸丨〇之前，將η-型 半導體基板1中之與ρ+型半導體區域3對應之部分自第2主 面lb側起薄化，而殘留該部分之周邊部分。藉此，可獲得 分別將n_型半導體基板1之第i主面la及第2主面lb側作為光 入射面之光二極體PD3。 (第4實施形態） 參照圖22〜圖24，對第4實施形態之光二極體之製造方法 146657.doc -18- 201101526 進行說明。圖22〜圖24係用以對第4實施形態之光二極體之 製造方法進行說明之圖。 第4實施形態之製造方法中，直至對n-型半導體基板i進 行溥化為止’與第3實施形態之製造方法相同’而省略至 此為止之步驟之說明。自第2主面ib側對η·型半導體基板i •進行研磨’使π型半導體基板1成為所需厚度之後，於n-型 半導體基板1之已薄化之部分之第2主面lb側形成累積層 11 (參照圖22)。累積層11之形成係與第j實施形態同樣地進 〇 行。累積層11之厚度例如為3 μπι左右。 繼而，對η_型半導體基板【之第2主面115照射脈衝雷射光 PL，而形成不規則之凹凸10(參照圖23)。不規則之凹凸1〇 之形成係與第1實施形態同樣地進行。 其次，與第1實施形態同樣地，對n-型半導體基板1進行 熱處理。繼而’於將形成於絕緣層7上之鈍化層9除去之 後’形成電極13、15(參照圖24)。藉此，完成光二極體 PD4 〇 〇 於第4實施形態中’亦與第卜第3實施形態同樣地，入射 至光二極體PD4之光之行進距離變長，吸收光之距離亦變 ' 長。藉此’光一極體PD4中’亦可提高於近紅外光之波長 . 帶域之光譜靈敏度特性。 第4實施形態中，於形成累積層U之前，將n-型半導體 基板1中之與Ρ +型半導體區域3對應之部分自第2主面化側 起薄化’而殘留該部分之周邊部分。藉此，可獲得分別將 η型半導體基板1之第1主面1 a及第2主面lb側作為光入射面 146657.doc 19· 201101526 之光二極體PD4。 (第5實施形態） 參照圖25〜圖32，對第5實施形態之光二極體之製造方法 進行說明。圖25〜圖32係用以對第5實施形態之光二極體之 製造方法進行說明之圖。 首先，準備第1半導體基板21與第2半導體基板23,將第 1半導體基板21直接貼附於第2半導體基板23之表面23b(參 照圖 25)。藉此，構成了 DBW(Direct Bonding Wafer，直接 接合晶圓）。第1半導體基板21及第2半導體基板23均包含 顯示η型之矽層。即，本實施形態中，由第1半導體基板21 與第2半導體基板23構成矽基板。 第2半導體基板23係與第1半導體基板21相比較，η型之 雜質濃度較高，因此比電阻低於第1半導體基板21。第1半 導體基板21之面方位為（ill)面方位，第2半導體基板23之 面方位為（100)面方位。第1半導體基板21之比電阻例如為 3 00〜600 Qcm左右。第2半導體基板2：3之比電阻為 0.001〜0.004 Qcm左右。第1半導體基板21之厚度例如為9 μπι左右。弟2半導體基板23之厚度例如為100 μπι左右。亦 可藉由在將第1半導體基板21與第2半導體基板23貼附之 後，分別對第1半導體基板21與第2半導體基板23進行研 磨，而獲得所需厚度。 其次，於第1半導體基板21之表面21a(DBW之第1主面） 側’形成P+型半導體區域3及n+型半導體區域5(參照圖 26)。於第1半導體基板21之表面21 a側形成絕緣層7(參照圖 146657.doc -20- 201101526 26)。第1半導體基板21之表面21a係與和第2半導體基板23 之貼附面（表面21b)對向之表面。p+型半導體區域3、n+型 半導體區域5及絕緣層7可與第1實施形態同樣地形成。本 實施形態中’ p+型半導體區域3之厚度例如為0.55 μιη左 右’薄片電阻例如為44 Ω/sq.。η+型半導體區域5之厚度例 如為1.5 μηι左右’薄片電阻例如為12 Ω/sq.。絕緣層7之厚 度例如為0.1 μιη左右。 繼而’於ρ+型半導體區域3上之絕緣層7中形成接觸孔 Η1，於η+型半導體區域5上之絕緣層7中形成接觸孔Η2(參 照圖27)。 其次，將於與通過接觸孔Η2而露出之η+型半導體區域5 對應之位置形成有開口的掩模形成於絕緣層7中。繼而， 對於開口中露出之η+型半導體區域5之表面進行乾式蝕 刻’直至第2半導體基板23之表面23b(與第1半導體基板21 之貼附面）之一部分露出為止（參照圖28)。藉由該蝕刻處 理’而於第1半導體基板21中設置傾斜狀部25。 繼而，藉由離子植入等將η型雜質添加於傾斜狀部25中 (參照圖29)。藉此，η+型半導體區域5係以包括傾斜狀部25 之方式擴張至第1半導體基板21之表面2 lb(與第2半導體基 板2 3之貼附面）為止。 其次，將第2半導體基板23中之與p+型半導體區域3對應 之部分自第2半導體基板23之表面23a(DBW之第2主面）側 起薄化，而殘留該部分之周邊部分（參照圖3〇)。第2半導體 基板23之表面23a係與和第i半導體基板21之貼附面（表面 146657.doc -21 - 201101526 23b)對向之表面。第2半導體基板23之薄化係可與第3實施 形態同樣地’藉由驗性钮刻之各向異性银刻而進行。第2 半導體基板23之經薄化之部分之厚度例如為3 μηι左右。 繼而，對第2半導體基板23之表面23a照射脈衝雷射光， 而形成不規則之凹凸10(參照圖31)。不規則之凹凸10之形 成係與第1實施形態同樣地進行。 其次’與第1實施形態同樣地，於對DBW(第1半導體基 板21及第2半導體基板23)進行熱處理之後，形成電極13、 15(參照圖32)。藉此，完成光二極體Pd5。電極15以覆蓋 n+型半導體區域5及第2半導體基板23之表面23 b之方式而 形成。 於第5實施形態中，亦與第1〜第4實施形態同樣地，入射 至光二極體PD5之光之行進距離變長，吸收光之距離亦變 長。藉此，光二極體PD5中，亦可提高於近紅外光之波長 帶域之光譜靈敏度特性。第5實施形態中，第2半導體基板 23(經薄化之部分）作為累積層來發揮功能。 第5實施形態中，於形成不規則之凹凸丨0之前，將第2半 導體基板23中之與p +型半導體區域3對應之部分自第2半導 體基板23之表面23a側起薄化，而殘留該部分之周邊部 分。藉此’可獲得分別將第丨半導體基板21之表面21a及第 2半導體基板23之表面23a側作為光入射面之光二極體 PD5。光二極體PD5可進行覆晶安裝。 第5實施形態中’若將較第2半導體基板23更高之比電阻 之第1半導體基板21規定為I型，則藉由p+型半導體區域 146657.doc -22- 201101526 3、第1半導體基板21及第2半導體基板23，而光二極體pD5 構成了 PIN光二極體。 (第6實施形態） 參照圖33〜圖36 ’對第6實施形態之光二極體之製造方法 加以說明。圖33〜圖36係用以對第6實施形態之光二極體之 製造方法進行說明之圖。 第6實施形態之製造方法係直至藉由離子植入等將n型雜 質添加於傾斜狀部25中為止，與第5實施形態之製造方法 Ο 相同，而省略至此為止之步驟之說明。將第2半導體基板 23中之與〆型半導體區域3對應之部分自第2半導體基板幻 之表面23a(DBW之第2主面）側起除去，而殘留該部分之周 邊部分（參照圖33)。藉此，第i半導體基板21之表面21b中 之與p+型半導體區域3對應之區域露出。 第2半導體基板23之除去可與第5實施形態同樣地，藉由 鹼性蝕刻之各向異性蝕刻而進行。（1〇〇)面方位之第2半導 ◎ 體基板23可容易地進行驗性㈣。另—方面，（111)面方位 之第1半導體基板21係與（100)面方位之第2半導體基板23相 比較，鹼性蝕刻之速度慢大致1〇〇分之丨倍左右。因此， (111)面方位之第1半導體基板21作為蝕刻終止層來發揮功 月b藉此，可進行精度良好之蝕刻加工，並且蝕刻步驟中 之作業性提高。藉由使用上述DBW，利用面方位之敍刻速 率之不同，可精度良好地獲得均勻厚度之第1半導體基板 21 〇 其-人，於第1半導體基板21之表面21b中之與型半導體 146657.doc -23· 201101526 區域3對應之區域，形成累積層1丨（參照圖34)。累積層丨i之 形成係與第1實施形態同樣地進行。累積層丨丨之厚度例如 為3 μιη左右。 繼而，對第1半導體基板21之表面21b照射脈衝雷射光， 而形成不規則之凹凸10(參照圖35)。不規則之凹凸1〇之形 成係與第1實施形態同樣地進行。 其次’與第1實施形態同樣地，於對DBW(第1半導體基 板21及第2半導體基板23)進行熱處理之後，形成電極13、 1 5(參照圖3 6)。藉此，完成光二極體pD6。電極丨5係與第5 實施形態同樣地，以覆蓋n+型半導體區域5及第2半導體基 板23之表面23b之方式而形成。 於第6實施形態中，亦與第丨〜第5實施形態同樣地入射 至光二極體PD6之光之行進距離變長，吸收光之距離亦變 長。藉此，光二極體PD6中，亦可提高於近紅外光之波長 帶域之光譜靈敏度特性。光二極體PD6係與光二極體pD5 同樣地構成了 PIN光二極體。 第6實施形態中，於形成不規則之凹凸1〇之前，將第2半 導體基板23中之與〆型半導體區域3對應之部分自第2半導 體基板23之表面23a側起除去，而殘留該部分之周邊部 分。藉此，可獲得分別將第〗半導體基板21之表面2u及第 2半導體基板23之表面23a側作為光入射面之光二極體 PD6。光二極體ρ〇6可進行覆晶安裝。 以上，對本發明之較佳實施形態進行了說明，但本發明 並不限定於上述實施形態，於不脫離其主旨之範圍内可進 146657.doc -24- 201101526 行各種變更。 本實施形態中’遍及第2主面lb之整個表面照射脈衝雷 射光，而形成不規則之凹凸1 〇，但並不限定於此。例如， 亦可僅對η·型半導體基板1之第2主面lb中之與P+型半導體 區域3對向之區域照射脈衝雷射光，而形成不規則之凹凸 10。第5實施形態中，亦可僅對第2半導體基板23之表面 23a中之與p型半導體區域3對向之區域照射脈衝雷射光， 而形成不規則之凹凸10。第6實施形態中，亦可僅對第直半 Ο 導體基板21之表面21b中之與p+型半導體區域3對向之區域 照射脈衝雷射光，而形成不規則之凹凸丨〇。 本實施形態中，將電極15與形成於η·型半導體基板！之 第1主面la側之Π+型半導體區域5電性接觸且連接，但並不 限定於此。例如，亦可將電極15與形成於η·型半導體基板 1之第2主面lb側之累積層11電性接觸且連接。於該情形 時，較佳為於γΓ型半導體基板1之第2主面lb中之與p+型半 0 導體區域3對向之區域以外，形成電極15。其原因在於， 若於η型半導體基板1之第2主面ib中之與p +型半導體區域3 對向之區域形成電極15，則形成於第2主面lb之不規則之 凹凸10由電極15堵塞’而產生近紅外光之波長帶域中之光 譜靈敏度下降之現象。 亦可將本實施形態之光二極體PD1〜PD6中之p型及n型之 各導電型替換為與上述相反。 產業上之可利用性 本發明可用於半導體光檢測元件及光檢測裝置。 146657.doc -25- 201101526 【圖式簡單說明】 法進行說 决進行說 法進行說 法進行說 法進行說 圖1係用以對第1實施形態之光二極體之製造方 明之圖。 圖2係用以對第1實施形態之光二極體之製造方 明之圖。 圖3係用以對第1實施形態之光二極體之製造方 明之圖。 圖4係用以對第1實施形態之光二極體之製造方 明之圖。 圖5係用以對第1實施形態之光二極體之製造方 明之圖。 圖6係用以對第1實施形態之光二極體之製造方法進行說 明之圖。 圖7係用以對第1實施形態之光二極體之製造方法進行說 明之圖。 圖8係用以對第1實施形態之光二極體之製造方法進行說 明之圖。 圖9係用以對第1實施形態之光二極體之製造方法進行說 明之圖。 圖10係用以對第1實施形態之光二極體之製造方法進行 說明之圖。 圖11係表示第1實施形態之光二極體之構成之圖。 圖12係表示實施例1及比較例1中之光譜靈敏度相對於波 長之變化之線圖。 146657.doc -26- 201101526 圖13係表示實施例1及比較例1中之溫度係數相對於波長 之變化之線圖。 圖14係用以對第2實施形態之光二極體之製造方法進行 說明之圖。 圖15係用以對第2實施形態之光二極體之製造方法進行 • 說明之圖。 圖16係用以對第2實施形態之光二極體之製造方法進行 說明之圖。 〇 圖17係用以對第3實施形態之光二極體之製造方法進行 說明之圖。 圖18係用以對第3實施形態之光二極體之製造方法進行 說明之圖。 圖19係用以對第3實施形態之光二極體之製造方法進行 說明之圖。 圖20係用以對第3實施形態之光二極體之製造方法進行 說明之圖。 〇 圖21係用以對第3實施形態之光二極體之製造方法進行 說明之圖。 圖22係用以對第4實施形態之光二極體之製造方法進行 • 說明之圖。 圖23係用以對第4實施形態之光二極體之製谂方法進行 說明之圖。 圖24係用以對第4實施形態之光二極體之製遠方法進行 說明之圖。 146657.doc -27- 201101526 圖2 5係用以斜第5實施形態之光二極體夂製造方法進 說明之圖。 丁 圖2 6係用以_第5實施形態之光二極體造方法 說明之圖。 订Damage to defects, etc. However, in the present invention, after the step of forming the accumulation layer of the i-th conductivity type, the substrate is subjected to heat treatment, and the crystallinity of the cut substrate is restored, thereby preventing defects such as an increase in dark current. Preferably, the method includes the steps of: thinning the portion of the substrate corresponding to the semiconductor region of the second conductivity type from the second main surface side before the step of forming the irregular concavities and convexities, leaving the periphery of the portion section. In this case, an optical diode in which the i-th main surface and the second main surface side of the broken substrate are respectively used as light incident surfaces can be obtained. A method of manufacturing a photo-polar body according to the present invention includes the steps of: preparing a ruthenium substrate including a semiconductor of a first conductivity type, having a first main surface and a second main surface facing each other, and on the side of the main surface a semiconductor region of the second conductivity type is formed; a first conductivity type accumulation layer having a higher impurity concentration than the germanium substrate is formed on the second main surface side of the germanium substrate; after the step of forming the third conductivity type accumulation layer And irradiating the region facing at least the second conductivity type semiconductor region with respect to the second main surface of the Shishi substrate to irradiate the pulsed laser light to form irregular concavities and convexities; and after the step of forming the irregular concavities and convexities, The substrate is subjected to heat treatment. In the method of manufacturing a photodiode of the present invention, as described above, the traveling distance of the light incident on the photodiode becomes longer, and the distance of the absorbed light becomes longer, so that the wavelength band of the near-infrared light is 146657.doc 201101526 The spectral sensitivity characteristics are improved. By forming the first electric type accumulation layer on the second main surface side of the Shishi substrate, the dark current can be reduced, and the light detection sensitivity of the photodiode can be improved. In the present invention, after the step of forming irregular irregularities, the tantalum substrate is subjected to heat treatment, whereby the crystallinity of the tantalum substrate is restored, and defects such as an increase in dark current can be prevented. Preferably, the method further includes the step of: thinning the portion corresponding to the semiconductor region of the second conductivity type in the Si-Xu substrate from the second main surface side before the step of forming the accumulation layer of the second conductivity type, The peripheral portion of the portion remains. In this case, a photodiode having the second principal surface and the second principal surface of the tantalum substrate as the light incident surface can be obtained. The thickness of the cumulative layer of the 帛1 conductivity type is larger than the height difference of the irregular embossing. In this case, even after the step of forming the accumulation layer of the first conductivity type, the above-mentioned concave-convex accumulation layer which is irradiated with the pulsed laser light to form irregularities remains. Therefore, the effect of the above cumulative layer can be ensured. Preferably, in the step of preparing the ruthenium substrate, the ruthenium substrate is prepared on the first main surface side to form a ruthenium substrate ′ having a semiconductor region of a first conductivity type having a higher impurity concentration than the ruthenium substrate, and further includes the following Step: After the step of heat-treating the germanium substrate, an electrode electrically connected to the semiconductor region of the i-th conductivity type and an electrode electrically connected to the semiconductor region of the second conductivity type are formed. In this case, even if the electrode uses a metal t which has a relatively low melting point, the electricity 35 is not melted by the heat treatment step. Therefore, the electrode can be appropriately formed without being affected by the heat treatment. Preferably, in the step of forming the irregular concavities and convexities, the picoseconds 146657.doc 201101526 ~ femtosecond pulsed laser light is irradiated as pulsed laser light. In this case, irregular irregularities are easily formed. The photodiode of the present invention includes a germanium substrate including a semiconductor of a second conductivity type, having an i-th main surface and a second main surface facing each other, and a second conductivity type formed on the first main surface side. In the semiconductor region, an ith conductivity type accumulation layer having a higher impurity concentration than the ruthenium substrate is formed on the second main surface side of the ruthenium substrate, and at least the second conductivity type semiconductor 于 in the second main surface Irregular irregularities are formed in the region facing the region, and the region of the second conductive type semiconductor region facing the second main surface of the substrate is optically exposed. In the photodiode of the present invention, as described above, The traveling distance of the light incident on the photodiode becomes longer, and the distance of the absorbed light becomes longer, so that the spectral sensitivity characteristic in the wavelength band of the near-infrared light is improved. The second main surface side of the germanium substrate is formed. The accumulation layer of the second conductivity type can reduce the dark current and improve the light detection sensitivity of the photodiode. Preferably, the portion of the germanium substrate corresponding to the semiconductor region of the second conductivity type is from the second main surface side. Thinning while leaving the part In this case, it is possible to obtain a photodiode having the first main surface and the second main surface side of the ruthenium substrate as light incident surfaces. Preferably, the thickness of the accumulation layer of the first conductivity type is larger than irregular. In this case, as described above, the effect of the accumulation layer can be ensured. Preferably, the substrate includes: a second semiconductor substrate including a semiconductor of a first conductivity type; and a second semiconductor The substrate is attached to the semiconductor substrate 146657.doc 201101526, and includes a semiconductor of the first conductivity type, and has a higher impurity concentration than the semiconductor substrate, and the second semiconductor substrate and the second semiconductor substrate A semiconductor region of the second conductivity type is formed on the surface facing the facing surface, and is formed in the surface of the second semiconductor substrate facing the surface of the second semiconductor substrate and the second conductive type. Irregular concavities and convexities are formed in the region opposite to the semiconductor region. In this case, a PIN photodiode having improved spectral sensitivity characteristics in the wavelength band of near-infrared light can be realized. The invention includes a second semiconductor substrate including a second conductivity type semiconductor, and a second semiconductor substrate attached to the second semiconductor substrate, including a semiconductor of a first conductivity type, and having a second semiconductor substrate The second semiconductor type semiconductor region is formed on the surface of the second semiconductor substrate and the second semiconductor substrate facing the surface of the second semiconductor substrate, and at least the second surface of the i-th semiconductor substrate is bonded to the second semiconductor substrate. The opposite regions of the conductive semiconductor region are exposed and irregular irregularities are formed. In this case, the wavelength band of the near-infrared light can be realized. < PIN light diode with improved spectral sensitivity characteristics. Preferably, the surface orientation of the first semiconductor substrate is (111), and the surface orientation of the second semiconductor substrate is (1 〇 0). In this case, the bonded wafer can be used as the tantalum substrate (the first and second semiconductor substrates are different in the etching rate of the surface orientation, and the second semiconductor substrate having a uniform thickness can be obtained with high precision. Since the boundary surface with the second semiconductor substrate functions as an etching stopper layer, the workability in the etching step is excellent. Advantageous Effects of the Invention The present invention provides a method of manufacturing a photodiode and a photodiode 146657.doc 201101526, which is The photodiode system has a photodiode and has sufficient spectral sensitivity characteristics in the wavelength band of near-infrared light. [Embodiment] Hereinafter, reference is made to the accompanying drawings. <Detailed embodiments of the present invention will be described in detail. In the description, the same elements or elements having the same functions are denoted by the same reference numerals, and the description thereof will not be repeated. (First Embodiment) A method of manufacturing a photodiode according to the first embodiment will be described with reference to Figs. 1 to 10 . Fig. 1 to Fig. 10 are views for explaining a method of manufacturing the photodiode according to the first embodiment. First, an n-type semiconductor substrate 矽 (see FIG. 丨) including a bismuth (Si) crystal and having a second main surface la and a second main surface lb opposed to each other is prepared. The & type semiconductor substrate 1 has a thickness of about 300 μm and a specific resistance of about i kn.cm. In the present embodiment, the "high impurity concentration" means, for example, an impurity concentration of about 1 xio 17 cm·3 or more, and is expressed by adding "+" to the conductive type. Q "The low impurity concentration of the stomach" means, for example, that the impurity concentration is lxl〇15 or less, and is indicated by the addition of "_" to the conductivity type. As the n-type impurity, bismuth (Sb), arsenic (As) or phosphorus (yttrium) or the like is present, and boron (yttrium) or the like is present as the p-type impurity. Next, a p + -type semiconductor region 3 and an n-type semiconductor region 5 (see FIG. 2) are formed on the first main surface 1a side of the 1 - type semiconductor substrate 1. In the p + -type semiconductor region 3, a high-concentration p-type impurity is diffused from the second principal surface la side in the type semiconductor substrate 1 by using a mask such as a t-port opening, thereby forming a +n-type semiconductor region 5 by The n-type impurity of the n-type semiconductor substrate is more concentrated in the n-type semiconductor substrate 1 by using another mask or the like opening in the peripheral portion region so as to surround the P + -type semiconductor region 3 so as to be more concentrated than the n-type semiconductor substrate 146. The first main surface la side is formed by diffusion. The thickness of the P + -type semiconductor region 3 is, for example, about μ55 μηη, and the sheet resistance is, for example, 44 Ω/sq. The thickness of the η + -type semiconductor region 5 is, for example, about 15 μm, and the sheet resistance is, for example, 12 Ω/sq. Then, an insulating layer 7 is formed on the first main surface 1a side of the n-type semiconductor substrate 1 (see Fig. 3). The insulating layer 7 contains Si〇2 and is formed by thermally oxidizing the n-type semiconductor substrate 1. The thickness of the insulating layer 7 is, for example, about 0 丨 μηη. Thereafter, a contact hole hi is formed in the insulating layer 7 on the p-type semiconductor region 3, and a contact hole 2 is formed in the insulating layer 7 on the n + -type semiconductor region 5. Instead of the insulating layer 7, an anti-reflective (ar, anti-reflective) layer containing SiN may be formed. A passivation layer 9 is formed on the second main surface ib of the π-type semiconductor substrate 1 and on the insulating layer 7 (see FIG. 4). The passivation layer 9 contains SiN by, for example, chemical vapor deposition (Chemical Vapor Deposition). Vapor deposition) method to open > into. The thickness of the purification layer 9 is, for example, 0.1. Then, the n-type semiconductor substrate 1 is polished from the second main surface 1 b side so that the thickness of the n-type semiconductor substrate i becomes a desired thickness (see Fig. 5). Thereby, the passivation layer 9 formed on the second main surface 1b of the ?-type semiconductor substrate 1 is removed, and the ?-type semiconductor substrate j is exposed. Here, the surface to be exposed by the polishing is also required to have a thickness of, for example, 27 〇 μηη as the second main surface lb °. Then, the second principal surface 丨b of the n-type semiconductor substrate 照射 is irradiated with the pulsed laser light PL' to form irregular irregularities 1 (see Fig. 6). Here, as shown in Fig. 7, the n-type semiconductor substrate 1 is placed in the chamber c, and the pulse laser generating device PLD disposed outside the chamber c irradiates the pulsed laser light PL to the n-type semiconductor substrate. The chamber C includes a gas introduction unit gin and a gas discharge unit 146657.doc -10- 201101526 G0UT 'Inert gas (for example, nitrogen gas or argon gas) is introduced from the gas introduction unit Gw and then discharged from the gas discharge unit G〇UT. An inert gas flow Gf is formed in the chamber C. The dust or the like generated when the pulsed laser light PL is irradiated is discharged to the outside of the chamber C by the inert gas flow Gf, and the processing chips or dust are prevented from being attached to the ITO-type semiconductor substrate 1. In the present embodiment, the picosecond to femtosecond pulse laser generating apparatus is used as the pulse laser generating apparatus PLD, and the picosecond to femtosecond pulsed laser light is irradiated over the entire surface of the second main surface lb. The second main surface lb is subjected to picoseconds to femtosecond pulses © lasing laser light destruction, and as shown in Fig. 8, irregular irregularities 10 are formed on the entire surface of the second main surface lb. The irregular concavity 1 has a surface which is intersected with respect to the direction orthogonal to the first main la. The height difference of the concavities and convexities is, for example, about 0.5 to 10 μm, and the interval between the convex portions in the concavities and convexities is 〇5 to 1 〇 μηι. The pulse time width of the picosecond to femtosecond pulsed laser light is, for example, about 50 fs to 2 ps, and the intensity is, for example, about 4 to 16 GW. The pulse energy is, for example, about 200 to 800 pj/pulse. More generally, the peak intensity is about 3xl 〇 U~2.5xl013 (W/Cm2) ’ flux is about 3 (J/cm 2 ). Fig. 8 is a view showing an SEM (scann electron microscope) image of irregular irregularities formed on the second main surface 1b. Next, an accumulation layer 11 is formed on the second main surface 1b side of the n-type semiconductor substrate 1 (see Fig. 9). Here, the n-type impurity is ion-implanted or diffused from the second main surface 1 b side in the n-type semiconductor substrate i so as to become a higher impurity concentration than the n-type semiconductor substrate ,, thereby forming an accumulation. Layer 1丨. The thickness of the accumulation layer is, for example, about 1 μπι. 146657.doc 201101526 Then, the n-type semiconductor substrate 1 is subjected to heat treatment (annealing). Here, the η-type semiconductor substrate 1 is heated in a range of about 800 to 10,000 ° C in an atmosphere of N 2 gas for about 0.5 to 1 hour. Next, after the passivation layer 9 formed on the insulating layer 7 is removed, the electrodes 13 and 15 are formed (see Fig. 10). The electrode 13 is formed in the contact hole, and the electrode 15 is formed in the contact hole H2. The electrodes 13, 15 respectively include Ai or the like, and have a thickness of, for example, about 1 μη. Thereby, the photodiode PD1 is completed. As shown in FIG. 10, the photodiode PD1 includes an n-type semiconductor substrate i. A p + -type semiconductor region 3 and a ?-type semiconductor region 5' are formed on the first main surface 1a side of the ?-type semiconductor substrate 1 to form a pn junction between the n-type semiconductor substrate 1 and the p + -type semiconductor region 3. The electrode 13 is electrically contacted and connected to the p + -type semiconductor region 3 through the contact hole H1. The electrode 15 is electrically contacted and connected to the n + -type semiconductor region 5 through the contact hole H2. Irregular irregularities 10 are formed on the second main surface 1b of the ?-type semiconductor substrate 1. The accumulation layer u is formed on the second main surface ib side of the n-type semiconductor substrate 1, and the second main surface lb is optically exposed. The second main surface lb is optically exposed, and not only the second main surface 1b is in contact with an ambient gas such as air, but also includes an optically transparent crucible formed on the second main surface 1b. In the photodiode PD1, irregular concavities and convexities 10 are formed on the second main surface lb. Therefore, as shown in Fig. 11, the light incident on the photodiode pm [reflects, scatters or diffuses by the concave projection 10, and travels a long distance in the n-type semiconductor substrate. Generally, the refractive index n = 3 5 ' with respect to Si and the refractive index n of air = 1.0. In the case of the light diode, when the light is incident from the direction perpendicular to the light incident surface, 146657.doc 12·201101526, the light that is not absorbed in the photodiode (the substrate) is divided into the back surface of the light incident surface. Light component and light component that penetrates the light diode. The light that penetrates the photodiode is not conducive to the sensitivity of the photodiode. The light component reflected by the back surface of the light incident surface is absorbed in the photodiode, and becomes a photocurrent. The unabsorbed light component is incident on the light incident surface and reflects or penetrates in the same manner as the light component reaching the back surface of the light incident surface. In the case where the light L enters the direction perpendicular to the light incident surface (the first main surface ia), the photodiode PD1 reaches the irregular unevenness 10 formed on the second main surface ib, and The direction of the exit is 166. The light component that reaches the above angle is totally reflected by the bump 1 〇. Since the unevenness is irregularly formed, it has various angles with respect to the outgoing direction, and the total reflected light component diffuses in various directions. Therefore, among the total reflected light components, there are light components absorbed inside the n-type semiconductor substrate 1, and there are light components reaching the second principal surface 丨a and the side surface. The light components that have reached the first main surface la and the side surface travel in various directions due to the diffusion on the concavities and convexities 1〇. Therefore, the possibility that the light component reaching the i-th main surface la and the side surface is totally reflected by the first main surface la and the side surface is extremely high. The light component totally reflected by the i-th principal surface u and the side surface is totally reflected on different surfaces, and the traveling distance becomes longer. The inside of the light-type semiconductor substrate 1 incident on the photodiode PD1 is absorbed by the n• type semiconductor substrate 1 while being traveled for a long distance, and is detected as a photocurrent. Most of the light L incident on the photo-polar body PD1 does not penetrate the photodiode PD1, and the propagation distance becomes long, and is absorbed by the type semiconductor substrate i. Therefore, the spectral sensitivity of the wavelength band in the near-infrared light in the optical diode PD1 is improved by 146657.doc •13·201101526. When the second main surface lb is formed with regular irregularities, the light components that reach the first main surface la and the side surface are diffused by the unevenness, but travel in the same direction. Thus, the first main surface 丨a and the side surface are reached. The light component is less likely to be totally reflected by the first main surface & Therefore, the light component penetrating through the second main surface 1& and the side surface and further in the second main surface ib increases, and the traveling distance of the light incident on the photodiode is short. As a result, it is difficult to improve the spectral sensitivity characteristics in the wavelength band of near-infrared light. Here, an experiment was conducted in order to confirm the effect of improving the spectral sensitivity characteristics of the wavelength band of the near-infrared light in the second embodiment. A photodiode having the above-described configuration (referred to as an embodiment 〇, and a photodiode having irregular irregularities not formed on the second main surface of the semiconductor substrate (referred to as Comparative Example 1) was produced, and each spectral sensitivity characteristic was examined. The example and the comparative example have the same configuration except that irregular irregularities are formed by irradiation of pulsed laser light. The size of the n-type semiconductor substrate 丨 is set to 65 mm×6 5 mm. The p + -type semiconductor region 3 is The size of the photosensitive region is set to $8 mm x 5.8 mm. The bias voltage VR applied to the photodiode is set to 〇V. The results are shown in Fig. 12. In Fig. 12, the spectral sensitivity characteristics of the example 丨It is represented by T1, and the spectral sensitivity characteristic of the comparative example is represented by the characteristic T2. In Fig. 12, the vertical axis represents the spectral sensitivity (mA/w), and the horizontal axis represents the wavelength of light (nm). The characteristics indicated by the line indicate a spectral sensitivity characteristic with a quantum efficiency (QE) of 1%, and a spectral sensitivity with a quantum efficiency of 5% by the characteristic indicated by a broken line. 146657.doc • 14_201101526. according to 12, for example, in 1 ο " nm, the spectral sensitivity in Comparative Example 1 was 0.2 A/W (QE = 25%) 'In contrast, the spectral sensitivity in Example 1 was 0.6 A/W (QE = 72%). The spectral sensitivity of the wavelength band in the near-infrared light is greatly increased. The temperature characteristics of the spectral sensitivity in Example 1 and Comparative Example 1 were also confirmed. Here, the ambient temperature was raised from 25 ° C to 6 ( Rc and study the spectral sensitivity characteristics, find 60. (: ratio of spectral sensitivity to light beta sensitivity at 25 °c (temperature coefficient). The results are shown in Figure 13. In Figure 13, implementation The characteristics of the temperature coefficient of Example 1 are represented by Τ3, and the characteristics of the temperature coefficient of Comparative Example 1 are represented by the characteristic Τ4. In Fig. 13, the vertical axis represents the temperature coefficient (% wide C), and the horizontal axis represents the wavelength of light. (nm) According to Fig. 13, for example, at 1064 nmT, the temperature coefficient in the comparative example is 0.7%/°C, whereas the temperature coefficient in Example 1 is 〇2%/(>c, temperature dependency. Lower. Generally, if the temperature rises, the absorption coefficient increases and the band gap energy decreases. In the first embodiment, the spectral sensitivity is also sufficiently high at room temperature. Therefore, the change in spectral sensitivity caused by the temperature rise is smaller than that of the comparative example 1. In the photodiode PD1, the n-type semiconductor substrate is used. The accumulation layer 11 is formed on the second main surface lb side of i. Thereby, the unnecessary carriers which are not generated by light on the second main surface lb side are recombined, thereby reducing dark current. The accumulation layer is suppressed by The carrier generated by the light near the second main surface lb is captured by the second main surface lb. Therefore, the carrier generated by the light is efficiently moved toward the pn junction, thereby further improving the photodiode PD1. Light detection sensitivity. 146657.doc •15·201101526 In the first embodiment, after the accumulation layer 11 is formed, the n-type semiconductor substrate 1 is subjected to heat treatment. Thereby, the crystallinity recovery of the η-type semiconductor substrate 1 can prevent defects such as an increase in dark current. In the first embodiment, after heat treatment of the η-type semiconductor substrate 丨, the electrodes 13 and 15 are formed. Therefore, in the case where a metal having a relatively low melting point is used for the electrodes 13, 15, the electrodes 丨3, I5 are not melted by the heat treatment. Therefore, the electrodes 13, 15 can be appropriately formed without being affected by the heat treatment. In the first embodiment, the picosecond to femtosecond pulsed laser light is irradiated to form irregular irregularities 10. By this, it is possible to form irregular irregularities 10 ° as appropriate (Second Embodiment) A method of manufacturing the photodiode according to the second embodiment will be described with reference to Figs. 14 to 16 . Figs. 14 to 16 are views for explaining a method of manufacturing the photodiode according to the second embodiment. In the manufacturing method of the second embodiment, the n-type semiconductor substrate 1 is polished until the second main surface 沁 is polished, and the manufacturing method of the second embodiment is the same, and the steps up to the above are omitted. The semiconductor layer 1 is polished from the second main surface 1b to form the accumulation layer 11 on the second main surface 1b side of the n-type semiconductor substrate 使 after the n-type semiconductor substrate 丨 has a desired thickness (see FIG. 14). ). The formation of the accumulation layer 11 is performed in the same manner as in the Jth embodiment. The thickness of the accumulation layer 11 is, for example, about 1 μηη. Then, the second principal surface 115 of the η-type semiconductor substrate 1 is irradiated with the pulsed laser light PL' to form irregular irregularities 10 (see Fig. 15). Irregular irregularities are formed in the same manner as in the first embodiment. 146657.doc -16-201101526 Then, the n-type semiconductor substrate 1 is thermally treated in the same manner as in the first embodiment. Thereafter, after the passivation layer 9 formed on the insulating layer 7 is removed, the electrodes 13 and 15 are formed (see FIG. 16). Thereby, the photodiode PD2 is completed. In the second embodiment, as in the first embodiment, the traveling distance of the light incident on the photodiode PD2 becomes long, and the distance of the absorbed light also becomes long. Thereby, the optical diode PD2 can also be improved in spectral sensitivity characteristics in the wavelength band of near-infrared light. In the second embodiment, the thickness of the cumulative layer 大于 is larger than the height difference of the irregular unevenness j 〇 。. Therefore, even after the formation of the accumulation layer 11, the pulsed laser light is irradiated to form irregular irregularities 10, and the accumulation layer u remains reliably. Therefore, the effect of the accumulation layer 11 can be ensured. (Third Embodiment) A method of manufacturing a photodiode according to a third embodiment will be described with reference to Figs. 17 to 21 . Fig. 17 to Fig. 21 are views for explaining a method of manufacturing the photodiode according to the third embodiment. In the manufacturing method of the third embodiment, the method of manufacturing the first embodiment is the same as that of the first embodiment, and the steps up to the point are omitted. After the formation of the passivation layer 9, the portion of the n-type semiconductor substrate which corresponds to the material conductor region 3 is thinned from the second main surface (8), and the peripheral portion of the stomach portion remains (see Fig. 17). The n• type semiconductor substrate is thinned, for example, by using an anisotropic etching such as potassium hydroxide solution or TMAH (tetramethyi hydroxide, tetramethylammonium hydroxide solution). The n-type semiconductor substrate has a thinned thickness of, for example, 1 Å, and the thickness of the peripheral portion is, for example, about I46657.doc 17·201101526 300 μηη. (1) The thickness of the peripheral portion of the ?-type semiconductor substrate 1 is shown in Fig. 18 from the second main surface lb side to the n-type semiconductor substrate. The required thickness is, for example, 270 μm. 1 b illuminate pulsed laser light. In the same manner as in the first embodiment, the irregularities 1 〇 (see FIG. 9) are formed on the second main surface PL of the η-type semiconductor substrate 1 in the same manner as in the first embodiment. Then, on the η' type semiconductor substrate! The accumulation layer 11 is formed on the second main surface 部分 side of the thinned portion (see Fig. 20). The formation of the accumulation layer U is performed in the same manner as in the third embodiment. The thickness of the accumulation layer 11 is, for example, about 3 μηη. Then, in the same manner as in the first embodiment, after the η-type semiconductor substrate 1 is subjected to heat treatment, the passivation layer 9 formed on the insulating layer 7 is removed to form electrodes 13 and 15 (see Fig. 21). Thereby, the photodiode pd3 is completed. In the third embodiment, as in the case of the second embodiment and the second embodiment, the distance of the light incident on the light-emitting body PD3 becomes longer, and the distance of the absorbed light also becomes longer. Thereby, in the photodiode PD3, the spectral sensitivity characteristic of the wavelength band of the near-infrared light can be improved. In the third embodiment, the portion corresponding to the p + -type semiconductor region 3 in the n-type semiconductor substrate 1 is thinned from the second main surface lb side before the irregular concavities and convexities are formed, and the portion remains. The surrounding part. Thereby, the photodiode PD3 having the i-th principal surface la and the second main surface lb side of the n-type semiconductor substrate 1 as the light incident surface can be obtained. (Fourth Embodiment) A method of manufacturing a photodiode according to the fourth embodiment 146657.doc -18-201101526 will be described with reference to Figs. 22 to 24 . Fig. 22 to Fig. 24 are views for explaining a method of manufacturing the photodiode according to the fourth embodiment. In the manufacturing method of the fourth embodiment, the manufacturing method is the same as that of the third embodiment until the n-type semiconductor substrate i is deuterated, and the steps up to the above are omitted. The n-type semiconductor substrate i is polished from the second main surface ib side. After the π-type semiconductor substrate 1 has a desired thickness, the second main surface lb side of the thinned portion of the n-type semiconductor substrate 1 is formed. The accumulation layer 11 is formed (refer to FIG. 22). The formation of the accumulation layer 11 is performed in the same manner as in the jth embodiment. The thickness of the accumulation layer 11 is, for example, about 3 μπι. Then, the second principal surface 115 of the ?-type semiconductor substrate is irradiated with the pulsed laser light PL to form irregular irregularities 10 (see Fig. 23). The formation of irregular irregularities is performed in the same manner as in the first embodiment. Then, the n-type semiconductor substrate 1 is heat-treated in the same manner as in the first embodiment. Then, the electrodes 13 and 15 are formed after the passivation layer 9 formed on the insulating layer 7 is removed (see Fig. 24). In the same manner as in the third embodiment, the distance traveled by the light entering the photodiode PD4 becomes longer, and the distance of the absorbed light becomes longer. . Thereby, the 'optical body PD4' can also be increased in the wavelength of the near-infrared light. The spectral sensitivity characteristic of the band. In the fourth embodiment, before the accumulation layer U is formed, the portion of the n-type semiconductor substrate 1 corresponding to the Ρ + type semiconductor region 3 is thinned from the second main surface side, and the peripheral portion of the portion remains. . Thereby, the photodiode PD4 having the first main surface 1 a and the second main surface lb side of the n-type semiconductor substrate 1 as the light incident surface 146657.doc 19·201101526 can be obtained. (Fifth Embodiment) A method of manufacturing a photodiode according to a fifth embodiment will be described with reference to Figs. 25 to 32. Fig. 25 to Fig. 32 are views for explaining a method of manufacturing the photodiode according to the fifth embodiment. First, the first semiconductor substrate 21 and the second semiconductor substrate 23 are prepared, and the first semiconductor substrate 21 is directly attached to the surface 23b of the second semiconductor substrate 23 (see Fig. 25). Thereby, DBW (Direct Bonding Wafer) is constructed. Each of the first semiconductor substrate 21 and the second semiconductor substrate 23 includes an n-type germanium layer. In other words, in the present embodiment, the first semiconductor substrate 21 and the second semiconductor substrate 23 constitute a germanium substrate. In the second semiconductor substrate 23, since the n-type impurity concentration is higher than that of the first semiconductor substrate 21, the specific resistance is lower than that of the first semiconductor substrate 21. The surface orientation of the first semiconductor substrate 21 is (ill) plane orientation, and the surface orientation of the second semiconductor substrate 23 is (100) plane orientation. The specific resistance of the first semiconductor substrate 21 is, for example, about 300 to 600 Qcm. The specific resistance of the second semiconductor substrate 2:3 is about 0.001 to 0.004 Qcm. The thickness of the first semiconductor substrate 21 is, for example, about 9 μm. The thickness of the semiconductor substrate 23 is, for example, about 100 μm. After the first semiconductor substrate 21 and the second semiconductor substrate 23 are attached, the first semiconductor substrate 21 and the second semiconductor substrate 23 may be ground to obtain a desired thickness. Then, the P + -type semiconductor region 3 and the n + -type semiconductor region 5 are formed on the surface 21a (the first main surface of the DBW) side of the first semiconductor substrate 21 (see Fig. 26). An insulating layer 7 is formed on the surface 21a side of the first semiconductor substrate 21 (see Fig. 146657.doc -20-201101526 26). The surface 21a of the first semiconductor substrate 21 is a surface that faces the bonding surface (surface 21b) of the second semiconductor substrate 23. The p + -type semiconductor region 3, the n + -type semiconductor region 5, and the insulating layer 7 can be formed in the same manner as in the first embodiment. In the present embodiment, the thickness of the 'p + -type semiconductor region 3 is, for example, 0.55 μm, and the sheet resistance is, for example, 44 Ω/sq. The thickness of the η + -type semiconductor region 5 is, for example, about 1.5 μηι. The sheet resistance is, for example, 12 Ω/sq. The thickness of the insulating layer 7 is, for example, about 0.1 μm. Then, a contact hole Η1 is formed in the insulating layer 7 on the p + -type semiconductor region 3, and a contact hole Η 2 is formed in the insulating layer 7 on the n + -type semiconductor region 5 (refer to Fig. 27). Next, a mask in which an opening is formed at a position corresponding to the n + -type semiconductor region 5 exposed through the contact hole 2 is formed in the insulating layer 7. Then, the surface of the n + -type semiconductor region 5 exposed in the opening is dry etched until one of the surface 23b of the second semiconductor substrate 23 (the surface to be bonded to the first semiconductor substrate 21) is partially exposed (see Fig. 28). The inclined portion 25 is provided in the first semiconductor substrate 21 by the etching process'. Then, an n-type impurity is added to the inclined portion 25 by ion implantation or the like (see Fig. 29). Thereby, the n + -type semiconductor region 5 is expanded to the surface 2 lb (the surface to be bonded to the second semiconductor substrate 23) of the first semiconductor substrate 21 so as to include the inclined portion 25. Then, the portion of the second semiconductor substrate 23 corresponding to the p + -type semiconductor region 3 is thinned from the surface 23a (the second principal surface of the DBW) of the second semiconductor substrate 23, and the peripheral portion of the portion remains (see Figure 3〇). The surface 23a of the second semiconductor substrate 23 is opposed to the surface of the i-th semiconductor substrate 21 (surface 146657.doc - 21 - 201101526 23b). The thinning of the second semiconductor substrate 23 can be performed by the anisotropic silver etching of the indicia by the same manner as in the third embodiment. The thickness of the thinned portion of the second semiconductor substrate 23 is, for example, about 3 μm. Then, the surface 23a of the second semiconductor substrate 23 is irradiated with pulsed laser light to form irregular irregularities 10 (see FIG. 31). The shape of the irregular unevenness 10 is performed in the same manner as in the first embodiment. Then, in the same manner as in the first embodiment, the electrodes 13 and 15 are formed after heat treatment of the DBW (the first semiconductor substrate 21 and the second semiconductor substrate 23) (see Fig. 32). Thereby, the photodiode Pd5 is completed. The electrode 15 is formed to cover the n + -type semiconductor region 5 and the surface 23 b of the second semiconductor substrate 23. In the fifth embodiment, as in the first to fourth embodiments, the traveling distance of the light incident on the photodiode PD5 becomes long, and the distance of the absorbed light also becomes long. Thereby, in the photodiode PD5, the spectral sensitivity characteristics in the wavelength band of the near-infrared light can be improved. In the fifth embodiment, the second semiconductor substrate 23 (thinned portion) functions as an accumulation layer. In the fifth embodiment, the portion corresponding to the p + -type semiconductor region 3 in the second semiconductor substrate 23 is thinned from the surface 23a side of the second semiconductor substrate 23 before the irregular ridges 0 are formed, and remains. The peripheral part of the part. Thus, the photodiode PD5 having the surface 21a of the second semiconductor substrate 21 and the surface 23a of the second semiconductor substrate 23 as light incident surfaces can be obtained. The photodiode PD5 can be flip chip mounted. In the fifth embodiment, when the first semiconductor substrate 21 having a higher specific resistance than the second semiconductor substrate 23 is defined as an I-type, the p + -type semiconductor region 146657.doc -22-201101526 3, the first semiconductor substrate 21 and the second semiconductor substrate 23, and the photodiode pD5 constitutes a PIN photodiode. (Sixth embodiment) A method of manufacturing a photodiode according to a sixth embodiment will be described with reference to Figs. 33 to 36'. Figs. 33 to 36 are views for explaining a method of manufacturing the photodiode of the sixth embodiment. The manufacturing method of the sixth embodiment is the same as the manufacturing method of the fifth embodiment until the n-type impurity is added to the inclined portion 25 by ion implantation or the like, and the description of the steps up to here is omitted. The portion of the second semiconductor substrate 23 corresponding to the 〆-type semiconductor region 3 is removed from the phantom surface 23a (the second main surface of the DBW) of the second semiconductor substrate, and the peripheral portion of the portion remains (see FIG. 33). . Thereby, a region of the surface 21b of the i-th semiconductor substrate 21 corresponding to the p + -type semiconductor region 3 is exposed. The second semiconductor substrate 23 can be removed by anisotropic etching by alkaline etching in the same manner as in the fifth embodiment. (1〇〇) The second half of the plane orientation ◎ The body substrate 23 can be easily inspected (4). On the other hand, the first semiconductor substrate 21 of the (111) plane orientation is approximately twice as fast as about 1 〇〇 of the second semiconductor substrate 23 of the (100) plane orientation. Therefore, the first semiconductor substrate 21 of the (111) plane orientation functions as an etching stopper layer, whereby the etching process with high precision can be performed, and the workability in the etching step is improved. By using the DBW described above, the first semiconductor substrate 21 having a uniform thickness can be accurately obtained by using the above-described DBW, and the type semiconductor 146657 in the surface 21b of the first semiconductor substrate 21 can be accurately obtained. Doc -23· 201101526 The area corresponding to the area 3 forms a cumulative layer 1 (see Fig. 34). The formation of the cumulative layer 丨i is performed in the same manner as in the first embodiment. The thickness of the cumulative layer 例如 is, for example, about 3 μηη. Then, the surface 21b of the first semiconductor substrate 21 is irradiated with pulsed laser light to form irregular irregularities 10 (see FIG. 35). The irregular shape is formed in the same manner as in the first embodiment. Then, in the same manner as in the first embodiment, after the DBW (the first semiconductor substrate 21 and the second semiconductor substrate 23) is subjected to heat treatment, the electrodes 13 and 15 are formed (see Fig. 36). Thereby, the photodiode pD6 is completed. The electrode layer 5 is formed to cover the surface 23b of the n + -type semiconductor region 5 and the second semiconductor substrate 23 in the same manner as in the fifth embodiment. In the sixth embodiment, the distance of the light incident on the photodiode PD6 becomes longer as in the fifth to fifth embodiments, and the distance of the absorbed light also becomes longer. Thereby, in the photodiode PD6, the spectral sensitivity characteristic in the wavelength band of the near-infrared light can be improved. The photodiode PD6 constitutes a PIN photodiode in the same manner as the photodiode pD5. In the sixth embodiment, the portion corresponding to the 〆-type semiconductor region 3 in the second semiconductor substrate 23 is removed from the surface 23a side of the second semiconductor substrate 23, and the portion remains after the irregularities 1 形成 are formed. The surrounding part. Thereby, the photodiode PD6 having the surface 2u of the semiconductor substrate 21 and the surface 23a side of the second semiconductor substrate 23 as light incident surfaces can be obtained. The photodiode ρ〇6 can be flip-chip mounted. The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the invention. In the present embodiment, the pulsed laser light is irradiated over the entire surface of the second main surface 1b to form irregular irregularities 1 〇, but the invention is not limited thereto. For example, the region of the second main surface 1b of the n-type semiconductor substrate 1 facing the P + -type semiconductor region 3 may be irradiated with pulsed laser light to form irregular irregularities 10. In the fifth embodiment, only the region of the surface 23a of the second semiconductor substrate 23 facing the p-type semiconductor region 3 may be irradiated with pulsed laser light to form irregular irregularities 10. In the sixth embodiment, the pulsed laser light may be irradiated only to the region facing the p + -type semiconductor region 3 on the surface 21b of the first semi-conductor substrate 21 to form irregular concavities and convexities. In the present embodiment, the electrode 15 is formed on the ?-type semiconductor substrate! The Π+-type semiconductor region 5 on the first main surface la side is electrically connected and connected, but is not limited thereto. For example, the electrode 15 may be electrically connected to and connected to the accumulation layer 11 formed on the second main surface 1b side of the n-type semiconductor substrate 1. In this case, it is preferable to form the electrode 15 other than the region facing the p + -type semi-conductor region 3 in the second main surface 1b of the γ-ray type semiconductor substrate 1. The reason is that when the electrode 15 is formed in a region facing the p + -type semiconductor region 3 in the second main surface ib of the n-type semiconductor substrate 1, irregular irregularities 10 formed on the second main surface 1b are electrodes. 15 clogging' produces a phenomenon in which the spectral sensitivity in the wavelength band of near-infrared light decreases. The p-type and n-type conductivity types in the photodiodes PD1 to PD6 of the present embodiment may be replaced with the opposite ones. Industrial Applicability The present invention is applicable to a semiconductor photodetecting element and a photodetecting device. 146657.doc -25-201101526 [Simplified description of the drawings] The method of the method is described. The method of the method is described. Fig. 1 is a diagram for explaining the manufacture of the photodiode of the first embodiment. Fig. 2 is a view showing the manufacture of the photodiode of the first embodiment. Fig. 3 is a view showing the manufacture of the photodiode of the first embodiment. Fig. 4 is a view showing the manufacture of the photodiode of the first embodiment. Fig. 5 is a view for explaining the manufacture of the photodiode of the first embodiment. Fig. 6 is a view for explaining a method of manufacturing the photodiode according to the first embodiment. Fig. 7 is a view for explaining a method of manufacturing the photodiode of the first embodiment. Fig. 8 is a view for explaining a method of manufacturing the photodiode of the first embodiment. Fig. 9 is a view for explaining a method of manufacturing the photodiode according to the first embodiment. Fig. 10 is a view for explaining a method of manufacturing the photodiode of the first embodiment. Fig. 11 is a view showing the configuration of an optical diode of the first embodiment. Fig. 12 is a graph showing changes in spectral sensitivity with respect to wavelength in Example 1 and Comparative Example 1. 146657.doc -26-201101526 Fig. 13 is a graph showing changes in temperature coefficient with respect to wavelength in Example 1 and Comparative Example 1. Fig. 14 is a view for explaining a method of manufacturing the photodiode of the second embodiment. Fig. 15 is a view for explaining the method of manufacturing the photodiode of the second embodiment. Fig. 16 is a view for explaining a method of manufacturing the photodiode of the second embodiment. Fig. 17 is a view for explaining a method of manufacturing the photodiode according to the third embodiment. Fig. 18 is a view for explaining a method of manufacturing the photodiode according to the third embodiment. Fig. 19 is a view for explaining a method of manufacturing the photodiode according to the third embodiment. Fig. 20 is a view for explaining a method of manufacturing the photodiode according to the third embodiment. Fig. 21 is a view for explaining a method of manufacturing the photodiode according to the third embodiment. Fig. 22 is a view for explaining the method of manufacturing the photodiode of the fourth embodiment. Fig. 23 is a view for explaining a method of manufacturing a photodiode according to the fourth embodiment. Fig. 24 is a view for explaining a method of manufacturing a photodiode according to the fourth embodiment. 146657.doc -27-201101526 Fig. 2 is a diagram for explaining the manufacturing method of the photodiode 斜 according to the fifth embodiment. Fig. 2 is a diagram for explaining the method of fabricating the photodiode according to the fifth embodiment. Order
系用以對第5實施形態之光一極體 < 遠方法 說明之圖。 T 圖28係用以對第5實施形態之光二極體 < 製造方法進 說明之圖。 丁 圖29係用以對第5實施形態之光二極體 < 數造方法進 說明之圖。 Τ 系用以對第5實施形態之光一極體 < 製造方法進 說明之圖。 丁It is a diagram for explaining the light-polar body < far method of the fifth embodiment. Fig. 28 is a view for explaining the method of manufacturing the photodiode of the fifth embodiment. Fig. 29 is a view for explaining a method of manufacturing a photodiode according to a fifth embodiment. Τ is a diagram for explaining the light-emitting body < manufacturing method of the fifth embodiment. Ding
圖31係用以對第5實施形態之光二極體 < 製造方法 說明之圖。 T 圖32係用以對第5實施形態之光二極體之製造方法進 說明之圖。Fig. 31 is a view for explaining the method of manufacturing the photodiode of the fifth embodiment. Fig. 32 is a view for explaining a method of manufacturing the photodiode of the fifth embodiment.
圖33係用以對第ό實施形態之光二極體之製造方法進 說明之圖。 T 圖34係用以對第6實施形態之光二極體史製造方法進 說明之圖。 订 之製造方法進行 圖35係用以對第6實施形態之光二極體 說明之圖。 圖36係用以對第6實施形態之光二極體之製造方法進行 說明之圖。 146657.doc -28- 201101526 【主要元件符號說明】 1 n型半導體基板 la 第1主面 lb 第2主面 3 P+型半導體區域 5 n+型半導體區域 10 不規則之凹凸 11 累積層 13 ' 15 電極 HI、 H2 接觸孔 PDL· -PD6 光二極體 PL 脈衝雷射光 Ο 146657.doc 29·Fig. 33 is a view for explaining a method of manufacturing the photodiode of the second embodiment. Fig. 34 is a view for explaining the method of manufacturing the history of the photodiode of the sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 35 is a view for explaining the photodiode of the sixth embodiment. Fig. 36 is a view for explaining a method of manufacturing the photodiode of the sixth embodiment. 146657.doc -28-201101526 [Description of main components] 1 n-type semiconductor substrate la 1st main surface lb 2nd main surface 3 P+ type semiconductor region 5 n+ type semiconductor region 10 Irregular unevenness 11 Accumulating layer 13 ' 15 Electrode HI, H2 contact hole PDL·-PD6 photodiode PL pulse laser diaphragm 146657.doc 29·