1221002 玖、發明說明 (發明說明應敘明：發明所屬之技術領域、先前技術、內容、實施方式及圖式簡單說明） (一） 發明所屬之技術領域 本發明是關於一種用以使表面平坦性優越且無間隙而連 續性優越的磷化硼系半導體層在矽單晶基板表面等之基底 表面上作氣相成長的氣相成長技術。 (二） 先前技術 自古以來，磷化硼（BP)是作爲III-V族化合物半導體之 一種且爲眾所皆知者。（請參閱寺本巖著，「半導體裝置 槪論」（1 9 9 5年3月3 0日，培風館股份有限公司發行初版 第28頁）。按由以磷化硼等之硼（B)與磷（P)作爲構成元素 而含有的磷化硼系半導體所構成之結晶層，是例如作爲緩 衝層來使用於構成發光元件（請參閱美國專利第6,069,02 1 號），或作爲用以形成歐姆（Ohmic)性電極的接觸（contact) 層來使用（請參閱日本專利特開平第2 - 2 8 8 3 9 9號公報）。另 在雷射二極體（LD)方面，則ί共作建構活性層（發光層）的磷 化硼（ΒΡ)/氮化鋁鎵（GaxAh-χΝ: 0SXS1)超格子層之用 (請參閱上述特開平第2 - 2 8 8 3 8 8號公報）。由此種以氮（N) 爲構成元素而含有的ΠΙ族氮化物半導體層與磷化硼構成 之超格子層，也作爲對於發光層的包層（clad)而利用（請參 閱上述特開平第2 - 2 8 8 3 8 8號公報）。 磷化硼系半導體層是藉例如以矽（S i)單晶（矽）爲基板而 以有機金屬化學氣相沉積法（MOCVD法）等氣相成長手段 所形成（請參閱上述美國專利第6,0 6 9,0 2 1號）。如欲以 1221002 Μ O C V D法形成例如磷化硼，則以三乙基硼[(c 2 H 5) 3 B ]或磷 化氣（P Η 3)作爲原料而使用。（①請參閱上述美國專利第 6，069,021號）。另有依使用鹵化物之三氯化磷（pcl3)或三氯 化硼（B C 13)之鹵素氣相成長法而形成之手段也爲眾人所知 (① J. Crystal Growth，13/14(1972)，第 3 4 6 〜3 4 9 頁、及 ②「曰本結晶成長學會誌」、Vol. 25，No.3(1998)，第A 28 頁）。另也有依使用乙硼烷（B 2 Η 6)與磷化氫（ρ η 3)的氫化物 (hyride)氣相成長手段而形成（①請參閱j.app1. Phys.， 42(1) (1971))’ 弟 420 〜424 頁’及② j. Crystal growth， 70(1984)，第 507 〜514 頁）。 對於矽單晶基板表面上的磷化硼系半導體層之形成，一 向是在由石英材料等構成之氣相成長反應爐（氣相成長爐） 內實施（①請參閱庄野克房著，「半導體技術（上）」（1992 年6月25日，財團法人東京大學出版會發行第9版，第 74〜76頁））。其係在热相成長爐內部之載置台（sllscept〇r) 上載放矽單晶基板後，使載置台或矽單晶基板之溫度上升 至適合於形成磷化硼系半導體層的溫度。用以形成磷化硼 系半導體層之溫度，已揭示有例如9 0 〇 °C〜1，2 5 0 °C (請參閱 上述「半導體層技術（上）、第76頁」）。然後使硼等瓜族 元素之氣體原料與磷等V族元素之氣體原料流通於氣相成 長爐內’而開始形成磷化硼系半導體層，就是自古以來爲 一般所採取之磷化硼系半導體層之氣相成長方法（請參閱1221002 发明 Description of the invention (the description of the invention should state: the technical field to which the invention belongs, the prior art, the content, the embodiments, and the drawings) (1) the technical field to which the invention belongs The present invention relates to a method for flattening a surface A boron phosphide-based semiconductor layer that is superior and has no gaps and excellent continuity is a vapor-phase growth technique for vapor-phase growth on a substrate surface such as a silicon single crystal substrate surface. (II) Prior technology Boron phosphide (BP) has been known as a type III-V compound semiconductor since ancient times. (See Teramoto Iwa, "Semiconductor Device Theory" (March 30, 1995, published by Pui Fung Kwan Co., Ltd., first edition, page 28). Boron (B) and phosphorus (P) A crystalline layer composed of a boron phosphide-based semiconductor contained as a constituent element is used, for example, as a buffer layer to constitute a light-emitting element (see US Pat. No. 6,069,02 1), or to form an ohm. (Ohmic) contact layer (see Japanese Patent Laid-Open No. 2-2 8 8 3 9 9). For laser diodes (LD), they are used together Active layer (light emitting layer) of boron phosphide (BP) / aluminum gallium nitride (GaxAh-χN: 0SXS1) superlattice layer (see Japanese Patent Application Laid-Open No. 2-2 8 8 3 8 8). Such a superlattice layer composed of a group III nitride semiconductor layer and boron phosphide containing nitrogen (N) as a constituent element is also used as a clad for a light emitting layer (see above Japanese Patent Application Laid-open No. 2 -2 8 8 3 8 8). The boron phosphide-based semiconductor layer is made of, for example, silicon (Si) single crystal (silicon). The substrate is formed by a vapor growth method such as an organometallic chemical vapor deposition method (MOCVD method) (see the above-mentioned US Patent No. 6,0 6,9,21). To form, for example, 1221002 M OCVD, for example, phosphorus Boron is used with triethylboron [(c 2 H 5) 3 B] or phosphating gas (P Η 3) as raw materials. (① Please refer to the above-mentioned US Patent No. 6,069,021). The formation method using halogen vapor phase growth method of phosphorus trichloride (pcl3) or boron trichloride (BC 13) is also known (① J. Crystal Growth, 13/14 (1972), No. Pages 3 4 6 to 3 4 9 and ② "Journal of the Japanese Society for Crystal Growth", Vol. 25, No. 3 (1998), page A 28). Diborane is also used (B 2 依 6) It is formed by means of vapor phase growth of hydride with phosphine (ρ η 3) (①Please refer to j.app1. Phys., 42 (1) (1971)) 'Brother 420 ~ 424' and ② j Crystal growth, 70 (1984), pp. 507-514). The formation of a boron phosphide-based semiconductor layer on the surface of a silicon single crystal substrate has always been carried out in a vapor growth reactor (vapor growth furnace) made of quartz material or the like (1) Technology (Part 1) "(June 25, 1992, Tokyo University Press, 9th edition, pages 74 ~ 76). After the silicon single crystal substrate is placed on a mounting table (sllsceptor) inside the thermal phase growth furnace, the temperature of the mounting table or the silicon single crystal substrate is raised to a temperature suitable for forming a boron phosphide-based semiconductor layer. The temperature used to form the boron phosphide-based semiconductor layer has been revealed, for example, from 900 ° C to 1,250 ° C (see "Semiconductor Layer Technology (I), page 76" above). Then, a gas source of melon elements such as boron and a gas source of element V such as phosphorus are circulated in the gas phase growth furnace, and a boron phosphide-based semiconductor layer is formed, which is a boron phosphide-based semiconductor generally adopted since ancient times. Layer vapor growth method (see
Inst. Phys，Conf· Ser·，Νο·129(ΙΡ〇 pub· Ltd·, 1 9 9 3，UK) 第1 5 7〜1 62頁）。供用以使上述氣體原料輸送供應於氣相 1221002 成長爐內之氣體，一向是專門使用氫氣（h2)(請參閱上述 Inst. P h y s ? C ο n f. Νο·129) ο 另一方面，已知存在於矽單晶基板表面之氮化矽（Si3N4) 或二氧化矽（Si02)之被膜，是一種可作爲用以妨礙氮化鎵 (GaN)的成長之被覆（masking;遮蔽）材料（請參閱①J. Crystal Growth，230(2001))，第 341 〜346 頁、及②同誌第 3 4 6〜3 5 0頁）。基於如該等作用，氮化矽或氧化矽之被膜 ，是有效利用於爲使以氮爲構成元素而含有之DI族氮化物 系半導體層，限定於基板表面上經適當選擇的領域而形成 之選擇成長手段所需之基板表面被覆材料（請參閱「m族氮 化物半導體」（1 9 9 9年1 2月8日，培風館股份有限公司發 行初版，第1 2 2〜1 2 4頁）。 (三）發明內容 發明所欲解決之技術問題 在以往之磷化硼系半導體層形成技術，例如上述 BP/GaxAli_xN(0$XS 1)超格子層，是藉在同一氣相成長爐 內使BP結晶層與GaxAlhNCO S XS 1)結晶層交替疊層所 形成。因爲在同一氣相成長爐形成與如此般含有氮的ΠΙ族 磷化硼系半導體層之超格子層，所以在氣相成長爐內壁或 在載置台，一定會附著含有ΙΠ族氮化物結晶之分解生成物 。按構成m族氮化物半導體層的氮，是容易在先前一向慣 用的磷化硼系半導體層形成溫度之約爲1，〇 〇 〇 °c左右或超 過其之高溫下揮散（請參閱J. Phys. Chem·，6 9 ( 1 0 )( 1 9 6 5 ) ，第3，4 5 5〜3，4 6 0頁）。因此在爲形成磷化硼系半導體層 1221002 所需升溫階段，氮會由含有π族氮化物半導體結晶之分解 生成物中向氣相成長爐內部釋放。特別是因氮化銦（ΙηΝ) 之升華溫度在真空中會低至6 2 0 °C (請參閱曰本產業技術振 興協會新材料技術委員會編著、「化合物半導體裝虞」（1 9 7 3 年9月15日，（股份有限公司）工業調查會發行）第397頁） ，因而由含有氮化銦之分解生成物必會顯著地使氮釋放於 氣相成長爐內。 在高溫下排放於氣相成長爐內的部分氮，必會在矽單晶 基板表面起反應而形成氮化矽被膜。與上述瓜族氮化物半 導體層之正常形成會因氮化矽被膜而受到阻礙之情形同樣 地，因存在於氣相成長爐內的氮而形成於矽單晶基板表面 上之氮化矽被膜，也會妨害磷化硼系半導體層之形成。因 而必會被歸結爲凹凸激烈而缺乏連續性之磷化硼系半導體 層形成於矽單晶基板表面之磷化硼系半導體層，若一開始 就成爲缺乏表面之平坦性與連續性者，則不可能在其上再 形成出具連續性且表面平坦性優越的結晶層。若欲從此種 含有非連續性結晶層之疊層結構體來構成例如發光二極體 (L E D) ’則因結晶層的非連續性，或p ^結界面之非平坦性 所然’乃不可能製得正向電壓（所謂的Vf)低，且電流特性 優越的LED。 有* _於此’本發明是爲解決上述先前技術之問題而完成 胃目的在於揭示一種能抑制會阻礙對於矽單晶基板表 ® i % $磷化硼系半導體層的來自於黏附在氣相成長爐內 生成物的物質之排放抑制手段，藉以提供在矽單晶 1221002 基板表面上形成平坦性及連續性優越的磷化硼系半導體層 之氣相成長方法。 解決問題之技術手段 具體而言本發明爲： (1 ) 一種磷化硼系半導體層之氣相成長方法，係用以在氣 相成長爐內在矽（Si)單晶基板上以氣相成長手段使磷 化硼系半導體層氣相成長，其特徵爲：經使含有硼（B) 與磷（P)之氣體，與用以伴隨其之運載用氣體，流通於 氣相成長爐內，而在氣相成長爐內壁形成含有硼與磷 所構成之被膜後，使磷化硼系半導體層氣相成長於矽 單晶基板上。 (2 )如（1 )項記載之磷化硼系半導體層之氣相成長方法，其 中使上述運載用氣體爲以體積分率計含有60 %以上的 氬（Ar)之氣體。 (3 )如（1 )項或（2 )項記載之磷化硼系半導體層之氣相成長 方法’其中使含有硼之氣體爲含有有機硼化合物而未 含有鹵素之氣體。 (4) 如（1)至（3)項記載之磷化硼系半導體層之氣相成長方 法’其中使含有磷之氣體爲含有有機磷化氫化合物而 未含有鹵素之氣體。 (5) 如（1)至（4)項記載之磷化硼系半導體層之氣相成長方 法’其中在氣相成長爐內部配置未載放矽單晶基板之 基板載置台，邊使該基板載置台保持於5 〇 〇 °C以上 1200 1以下之溫度下，邊使含有硼（B)與磷（P)之氣體 -10- 1221002 與用以伴隨其之運載用氣體流通於氣相成長壚內，而 在氣相成長爐內壁形成含有硼與磷所構成之被膜。 (6) 如（1)至（5)項記載之磷化硼系半導體層之氣相成長方 法〃、中經在氣相成長爐內使m族氮化物半導體氣相 成長後，在氣相成長爐內壁形成含有硼與磷所構成之 被L 之後在同一氣相成長爐內使磷化硼系半導體層 氣相成長於矽單晶基板表面。 (7) 如（1 )至（6)項記載之磷化硼系半導體層之氣相成長方 法，其中經在氣相成長爐內壁形成含有硼與磷所構成 之被腠後，在基板載置台上載放矽單晶基板而配置於 氣相成長爐內部，使基板載置台溫度升溫於25 〇t：以 上1，2 0 0 °C以下範圍，而使磷化硼系半導體層氣相成長 於政單晶基板表面。 (8) —種磷化硼系半導體層，其特徵爲以上述（"至（？）項記 載之鱗化硼系半導體層之氣相成長方法所製得者。 (四）實施方式 發明之實施方式 本發明無論是MOCVD法、鹵素氣相成長法或氫化物氣 相成長方法等之成長手段差異，在含有氮（N)或氧（0)等之 分解生成物所存在的氣相成長爐內部使磷化硼系半導體層 氣相成長於矽單晶基板表面上時，特別能發揮功效。因此 ，基板可利用具有{ 1 0 0 }結晶面、{ 1 1 〇 }結晶面、或{ 1 1 1 } 結晶面之矽單晶（矽）。以向特定結晶方向而傾斜的結晶面 作爲表面之砂單晶也可作爲基板而利用。例如可以向< i i 〇 > -11- 1221002 結晶方向以角度計爲約傾斜7度（°)的{1 ο ο }結晶面作爲之 矽單晶，作爲基板而利用。若以η型或Ρ型傳導型之矽單 晶作爲基板，即可在基板背面配設正負任一極性之歐姆 (0 h m i c )性電極，·因而有助於以簡便方式構成發光元件或受 光元件等之用。尤其是對於電阻率爲1毫歐姆以下， 更佳爲0.1 ιηΩ以下的低比電阻（=電阻率）之導電性單晶基 板，將有助於製得正向電壓（所謂的Vf)低的LED。另外由 於散熱性優異，對於爲構成能提供穩定振盪之L D上有效。 供設於矽單晶基板表面上之磷化硼系半導體層，是指由 以硼與磷作爲構成元素而含有例如由BAAlBGacIiiDPidAw (〇<Α$1、〇gB<l、0SC<1、0SD<1、A + B + C + D = l、 OS δ< 1)構成之層，或例如由 BAAlBGacIriDPHN^fX AS 1 、0$B<1、〇gC<l、0 ^ D < 1 ' A + B + C + D = l、0 ^ δ < 1 ) 構成之層。本發明無論是供設在矽單晶基板表面上的磷化 硼系半導體層之構成形態，亦即無論是非晶質、多晶質或 單晶質’皆可適用。並且無論磷化硼系半導體層之傳導型 、或爲控制傳導型而故意加添的摻雜物（dopant)之種類、 運載用氣體（carrier)濃度、及層厚等，均能發揮本發明之 功效。更進一步並不限定於如同使上述磷化硼系半導體層 接合於砂單晶基板表面般使其氣相成長之情況，而特別是 對於使含氮（N)例如m族氮化物半導體層作爲氣相成長者 同一氣相成長爐內’使磷化硼系半導體層接合於同層上而 設之情況，也能發揮功效。 在本發明之第一實施方式，則在載置台載放如上述由矽 -12- 1221002 單晶基板所：成基板之前，％實施以含有硼與磷之被膜加 以被覆由石央材料、不銹鋼材料或氮化硼（BN)等陶瓷材料 作成的氣相成長爐內壁之操f乍。所謂的氣相成長爐之內壁 係指最靠近於基板而配置在基板周圍的構件之與基板相對 的內面之壁面。被膜，具體而言是藉由邊使石墨或碳化矽 (S i C )等耐闻溫材料構成之載置台保持於5 〇 〇 t以上1，2 0 〇 以下之溫度下邊使含有硼與_之氣體與伴隨其之運載用氣 體流通於氣相成長爐內而形成。藉此將附著於氣相成長爐 內壁而含有氮（N)的分解生成物之被膜加以被覆。 含有硼之氣體可使用三乙基硼[(C2H5)3B]、硼烷（Bh3)或 二硼烷（Β2ίί6)’含有磷之氣體可使用磷化氫（ph3)。爲在氣 相成長爐內壁形含有含有硼與磷之被膜而流通於氣相成長 爐內的磷原子濃度，則以設定爲超過硼原子濃度爲宜。例 如相對於硼原子濃度’約爲5倍以上，較佳爲1 0倍以上濃 度之磷原子供應於氣相成長爐內爲宜。在形成被膜時磷原 子濃度若未超過硼原子濃度’則實際要形成磷化硼系半導 體層時，由於磷易爲含有富裕的硼等m族構成元素的被膜 所吸收，因此會造成無法穩定地製得化學量論上保持均衡 而當量比優越的磷化硼系半導體層之問題。 載置台是藉由例如高頻加熱法、電阻加電法或紅外線加 熱法等手段來加熱。加熱載置台之目的爲使供給於氣相成 長爐內的含有硼與磷之氣體進行熱分解而生成供形成被膜 之硼與磷。雖也可採取藉由另外附設於氣相成長爐之專用 加熱裝置來使含有硼與磷之氣體進行熱分解之手段’但採 -13- 1221002 取直接加熱常備在氣相成長爐之載置台時，便可簡便地使 其產生熱分解。一般而言在未達約2 5 (TC之低溫下仍無法 使含有硼與磷之氣體進行充分的熱分解，因此不便於有效 地使含有硼與磷之被膜附著於氣相成長爐內壁。爲了有效 地形成出含有硼與磷之被膜，理應使載置台溫度達到5 0 0 °C 以上，以促進含硼氣體與磷氣體之熱分解爲宜。反之，在 超過1，2 0 0 °C之高溫下，由於磷等高揮發性之V族元素會 蒸發，結果所形成者將被歸結爲以m族元素爲富裕的被膜 ，而在製造當量比具均衡組成的磷化硼系半導體層上將帶 來阻礙。 較佳爲在適合於形成被膜上晚上述5 0 (TC以上且在 1，2 0 0 °c以下之溫度範圍內，儘使載置台溫度設定於高溫， 以使含磷氣體對於氣相成長爐內的供應量，相對於含硼氣 體之供應量而增加。此是在考量磷會在高溫環境下揮散而 爲了回避以HI族元素爲富裕的被膜黏附於氣相成長爐內壁 之故。此外也是爲了期能形成出能充分被覆含有氮（N)等的 分解生成物表面之含有硼與磷的被膜之緣故。含有硼與磷 的被膜之膜厚，應爲比含有氮（N )等的分解生成物之平均厚 度約爲兩倍以上，更佳爲約四倍以上。被膜若爲厚膜，則 容易自氣相成長爐內壁剝落。因而在磷化硼系半導體層之 氣相成長中，磷化硼系半導體層之表面狀態將因由氣相成 長爐內壁剝離而飛到矽單晶基板表面所附著的被膜小片而 受損。因此被膜之膜厚應以分解生成物平均厚度之約十倍 以內爲宜。被膜之膜厚是在加熱載置台時，控制對於氣相 1221002 成長爐內的含有硼與磷之氣體的流通時間’即可加以調整 。或者在一定的流通時間中’特別是將含硼氣體供應量 (=濃度）調整爲更多量，便能製得膜厚度更大的被膜。 本發明之第二實施方式’是於形成含有硼與磷之被膜時 ，採取特別是以氬（Ar)爲主體的氣體來運載含有該等元素之 氣體於氣相成長爐內之方法。因此該運載氣體將與含有硼與 磷之氣體一起被供給於氣相成長爐內而成爲構成氣相成長 爐內的氣氛者。換言之本發明第二實施方式之特徵爲在以 氬爲主體的氣氛中下形成含有硼與磷之被膜。所謂的主體是 指含有以體積分率計爲6 0 %以上之氬者。舉例說明，其有氬 單體（氬之體積分率=100 %)、氬（體積分率=70 %)與氫（H2)(體 積分率=3 0 % )之混合氣體等。氬體積分率可以氣體總體積中 所占的氬之體積分率來表示之。對於欲抑制釋放於氣相成長 爐內的氮（N)或氧（0)等之濃度的本發明宗旨而言，氬與氮（N 2) 、氬與氨（NH3)、或氬與氧（〇 2)等氬與含氮氣體或含氧氣體之 混合氣體是不能使用的。因爲會造成在矽單晶基板表面形成 由氮化矽或氧化矽構成之遮蔽（mas king)膜問題。按該遮蔽膜 是會阻礙磷化硼系半導體層的正常氣相成長。 譬如說，在氬與氫的混合氣體中，氬之體積分率是相對於 氬氣與氫氣之單位時間總流量而調整氬流量即可使其改變 。例如在氬與氫的混合氣體中，氬之體積分率變成爲60 %以 下時，氫與含在被膜之磷將化合，成爲高蒸氣壓的磷氫化物 而脫離，導致被膜將驟然受到顯著的侵蝕。由於此，被膜厚 度將減少’致使不能充分被覆含氮等的分解生成物之表面而 -15- 1221002 造成使氮等釋放於氣相成長爐內之問題。與氬屬同族的惰性 氣體之氦（He)或氖（Ne)雖也可作爲運載氣體而利用，但以經 濟觀點來看，最適合於形成含有硼與磷之被膜且爲屬惰性氣 體構成之運載氣體，還是爲由氬單體（氬之體積分率=100%) 構成之氣體。 本發明之第三實施方式，是於形成含有硼與磷之被膜時， 含有硼之氣體則選擇使用未含有氯（C1)或溴（Br)等鹵素之非 鹵化物。尤其是利用三甲基硼[(CH3)3B]、三乙基硼[(C2H5)3B] 等未含有鹵素之有機硼化合物。藉此即能回避起因於含鹵硼 化物在熱分解時所產生鹵素自由基或鹵素氣體的被膜侵蝕 現象。在硼的脂肪族飽和化合物中、三乙基硼在常溫下即具 有適度的蒸氣壓，因而方便於適當地調節與供流通於氣相成 長爐內的含磷氣體之流量比率。另外附加有含有氮（N)原子 或氧（0)原子之官能團的有機硼化合物，則不能供作形成被 膜之用。因爲會引導含有氮（N)或氧（〇)的被膜之形成而構成 對於氣相成長爐內的氮或氧之排放源。 本發明之第四實施方式，是於形成含有硼與磷之被膜時， 含有磷之氣體則選擇未含有氯（C1)或溴（Br)等鹵素之非鹵化 物而使用。特別是使用磷化氫（P Η 3)等未含有鹵素的氫化物 。含有鹵素之鹵化磷化合物，由於在其熱分解時會產生鹵 素而侵蝕被膜，使其薄層化且使分解生成物表面之被膜成 爲不完全者，所以不能使用。另外，磷化氫雖會呈路易斯 (Lewis)鹼性性質，但不會引起顯著的與三甲基硼或三乙基 硼等路易斯酸性化合物之複合體（ρ 0 1 0 m e r)化反應，因而具有 -16- 1221002 可在不致因該反應而受到徒然的浪費下即可以所期望之濃 度而送入於氣相成長爐內之優點。氫之外含有氮（N)原子或 氧（〇)原子的磷之氫化物，是不能利用於形成被膜之用。因 爲會引導含有氮（N)或氧（0)的被膜之形成而對於氣相成長爐 內構成氮或氧的排放源之故。 以磷化氫作爲含磷氣體使用時，因熱分解將在氣相成長 爐內依下列化學反應式（1)而產生氫氣（H2)。 PH3 — P + 3/2·Η2 化學反應式（1) 換言之，化學反應式（1)是表示若有ΡΗ3之1莫耳（mol.)完 全熱分解時，則將產生1.5莫耳之氫氣。因而若以上述氬 與氫的混合氣體作爲運載氣體，則必須使氬氣之體積分率， 設定成相對於構成混合氣體的氬氣、與氫氣、與經磷化氫之 熱分解而產生的氫氣之合計體積之6 0 %以上。因磷化氫之 熱分解產生的氫量，一般則應估爲因（PH3)之完全熱分解所 產生之量（每1莫耳之PH3爲1.5莫耳之氫）。 經在氣相成長爐內壁形成含有硼與磷之被膜後，則將載 置台溫度降溫至例如室溫附近之溫度，以便將矽單晶作爲 基板而載放於載置台上。然後經將矽單晶載放於經冷卻至 可供載放基板的溫度之載置台上規定位置後，以擺放著基 板之狀態下使載置台插放於氣相成長爐內之特定位置。在 此所謂的特定位置，是指在氣相成長爐內方便於均勻加熱 成磷化硼系半導體層氣相成長所需溫度之位置。然後使載 置台溫度升溫至適合於磷化硼系半導體層氣相成長之溫度 。對於矽單晶基板上的磷化硼系半導體層之氣相成長，可 •17- 1221002 藉由Μ O C V D法、鹵素氣相成長法、氫化物氣相成長法、 或瓦斯源分子束嘉晶生長法（請參閱Solid Stated Chem.， 133(1997)，第269〜272頁）等氣相成長手段而形成。 爲使非晶質或多晶之碟化硼系半導體層作氣相成長，則 以2 5 (TC〜7 5 0 °C之溫度爲適合。對於單晶狀磷化硼系半導 體層之氣相成長，則以7 5 〇 °C〜1，2 0 0 °C之溫度爲適合。超 過1，20(TC之高溫，由於會形成出B6P或B13P2等之聚合體 磷化硼，因而不便於以氣相成長組成上均勻的磷化硼系半 導體層。載置台溫度可藉例如熱電偶、放射溫度計等溫度 測定儀器來計測或調整。欲使載置台溫度進而使載放於載 置台之矽單晶基板溫度，升溫至適合於使上述磷化硼系半 導體層作氣相成長的溫度時，則將氣相成長爐內之氣氛以 含有以體積分率計爲60%以上的氬等惰性氣體之混合氣體 來構成爲宜。惟由氬單體（體積分率=100%)構成爲最適當。 以往一般採用的在氫氣氛中之升溫方式雖也屬可行，但在開 始磷化硼系半導體層進行氣相成長之前所黏附於氣相成長 爐內壁而含有硼與磷之被膜，將與氫起反應而導致被膜膜厚 減少之不良結果，所以未便採用。 茲舉例說明可顯不根據本發明實施方式而使含有硼與碟 之被膜預先形成於氣相成長爐內所顯現的效果之分析結果 如下。分析所使用之試樣是使用依Μ Ο C V D法使層厚爲6 2 0 奈米之氯化鎵·銦混晶（G a 〇. 9 〇 I n Q」G Ν )層作氣相成長，並利 用在氣相成長爐內壁特別是在載置台周邊黏附有平均層厚 爲約100奈米弱的分解生成物之氣相成長爐內而製得者。 1221002 首先於第1圖例示根據先前技術，即在氣相成長爐內壁 不Μ先形成含有硼與磷之被膜下，將具有{111}結晶面之矽 單晶基板加熱成1，0 5 0 t後之基板表面元素分析結果。經 加熱後之基板表面’雖不能明確地視認到有形成薄膜’但 是如依照俄歇（Auger)電子能譜（AES)，則如第1圖之光譜 所示，除氮（N)外’亦能確認到有碳（C)及氧（〇)之存在。由 此即得知，如欲在主要受到氮所污染的矽單晶基板表面上 ，使呈連續性且表面平坦性優越的磷化硼系半導體層作氣 相成長，則有困難。因而通常只能製得可歸結爲球狀結晶 體雜亂無章地疊成而表面粗糙的磷化硼系半導體層者而已。 接著，於第2圖例示根據本發明，即在上述氣相成長爐 內壁預先形成含有硼與磷且膜厚爲約3 0 0奈米之被膜後， 經在1，0 5 0 °C下將具有{ 1 11 }結晶面之矽單晶基板施予熱處 理後之基板表面元素分析結果。由第2圖所示之AES光譜 ，即可知除來自於基板之矽單晶的矽（S i)之A E S訊號外， 也能看得到微小而起因於碳（C)之AES訊號而已。另外也 能看得到來自於含有硼與磷的被膜之硼與磷之AE S訊號。 存在於矽單晶基板表面上之硼或磷，是提供磷化硼系半導 體層成長時所需之「成長核」，因而對於磷化硼系半導體層 氣相成長之順利進行上有效。因此依照本發明之被膜具有 能防止由發源於黏附在氣相成長爐內壁的分解生成物之氮 (N)、氧（0)所引起矽單晶基板表面污染之作用，極爲明確 。此種依本發明被膜之氮（N)及氧（0)表面污染之防止作用 ，例如經使m族氮化物半導體層氣相成長後，再使磷化硼 -19- 1221002 系半導體層氣相成長時也能顯現。惟在此種情況下，則在 結束如m族氮化物半導體層般含有氮的層之氣相成長後， 需要在進行磷化硼系半導體層氣相成長之前，預先形成含 有硼與磷之被膜。 作用 在進行磷化硼系半導體層之氣相成長以前，形成在氣相 成長爐內壁而含有硼與磷所構成之被膜，具有防止會妨害 磷化硼系半導體層正常成長之起源於氣相成長爐內分解生 φ 成物的基質表面污染之作用。 在進行磷化硼系半導體層之氣相成長以前，在氣相成長 爐內壁形成含有硼與磷所構成被膜時所使用之含有以體積 分率計爲6 0 %以上之氬的運載氣體，能在氣相成長爐內創 出含氬氣氛，且有抑止上述被膜之膜厚減少之作用。 在進行磷化硼系半導體層之氣相成長以前，在氣相成長 爐內壁形成含有硼與磷所構成之被膜時所使用之屬非鹵素 化合物的有機硼化合物，能供應會因熱分解而構成被膜之 # 硼，且具有回避經形成的被膜之膜厚減少之作用。 在進行磷化硼系半導體層之氣相成長以前，在氣相成長 爐內壁形成含有硼與磷所構成之被膜時所使用之屬非鹵素 化合物的有機硼化合物，能供應會因熱分解而構成被膜之 硼，且具有回避經形成的被膜之膜厚減少之作用。 實施例 (實施例） ~ 茲以藉由Μ Ο C V D法直接使單體磷化硼（b 〇 r ο η -20- 1221002 m ο η 〇 p h 〇 s p h i d e )氣相成長於具有添加有硼的p型{ 1 1 1 }結晶 面之矽單晶基板表面之場合爲例，具體說明本發明之內容 如下。於第3圖展示利用於本實施例之Μ Ο C V D氣相成長 裝置之模式結構。 第3圖所示之氣相成長裝置，其氣相成長爐11是由半導 體工業用之高純度石英管構成。在圓形的氣相成長爐11 之大致中央配置有供載放基板的高純度石墨製之圓柱狀載 置台12。在載置台12周邊的氣相成長爐11之外周部配置 _ 有高頻線懂1 3。在氣相成長爐1 1之一端設有導入口 1 4， 用以對爐內供應使用於含有硼與磷之被膜的形成或磷化硼 層之氣相成長之含有硼與磷之氣體及運載氣體。此外在氣 相成長爐Π之另一端設有排氣口 1 5，用以使沿著氣相成 長爐11之內壁11a而流通於載置台12周圍之氣體連同運 載氣體一起排放於爐外。 欲形成本發明之被膜時，則首先以氬氣作爲運載氣體而 以每分1 2公升之流量經由導入口 1 4供應於氣相成長爐1 1 φ 內部。自開始流通氬氣起，約經過2 0分鐘後，對高頻線圈 1 3接通高頻電源，使未載放有矽單晶基板的載置台1 2之 溫度自室溫升溫於9 0 0 °C。然後經確認藉由***於載置台 1 2內部之熱電偶1 6所檢測之溫度趨於穩定後，經由導入 口 14，使三乙基硼[(C2H5)3B]與磷化氫（PH3)連同上述流量 之運載氣體而供應於氣相成長爐11內。三乙基硼之供應量 ' 是設定於以流量計爲每分鐘約4cc，磷化氫之流量則設定 ' 於每分鐘約2 0 0 cc。藉此使氣相成長爐1 1之內部壓力維持 1221002 於大致爲大氣壓下，將三乙基硼[(c2h5)3b]與磷化氫（ph3) 對於氣相成長爐1 1內繼續供應6 0分鐘，俾在氣相成長爐 1 1之內壁1 1 a形成膜厚爲約4 0 0奈米之含有硼與磷之被膜 17。由於作爲含有硼與磷之氣體是使用含有屬非鹵素化合 物之有機硼化合物與磷化氫化合物之氣體，因此不會受到 顯著的蝕刻，其膜厚則與供應三乙基硼[(C2H5)3B]及磷化 氫（PH3)之時間大致成正比例而增加。 然後停止對氣相成長爐1 1內部供應三乙基硼[(C 2 Η 5) 3 B ] 及磷化氫（ΡΗ3)，對於爐內則由導入口 14只使作爲運載氣 體之氬氣以上述流量下繼續供應。接著停止載置台1 2之高 頻感應加熱，使載置台1 2之溫度下降。經降溫後，則將載 置台1 2暫時由氣相成長爐1 1取出於爐外，並在載置台1 2 之上面中央部載放上述具有Ρ型{ 1 1 1 }結晶面之矽單晶基 板以作爲基板1 〇 1。之後將載放有基板1 〇 1之載置台1 2再 度***於氣相成長爐1 1之特定位置。經***後，則在氣相 成長爐11之內部再以每分鐘12公升量下由導入口 14供應 氬氣。之後，在由氬構成之氣氛中藉高頻感應加熱手段使 載置台1 2之溫度升溫至8 5 (TC。載置台1 2之溫度剛到達 8 5 (TC之後，在實施磷化硼層的氣相成長之前，使作爲運載 氣體而使用的氬氣之流量自每分鐘1 2公升減至每公鐘1 0 公升。同時將流量每分鐘2公升之氫氣加添於氬氣，而重 新以氬之體積分率約爲8 3 . 3 %之A r _ Η 2混合氣體作爲運載 氣體而使用。 暫時使Ar-H2混合氣體流通於氣相成長爐1 1之內部後， -22- 1221002 在該混合氣體中加添了三乙基硼[(c2h5)3b]與磷化氫（ph3) 。三乙基硼[(C2H5)3B]之加添量爲每分鐘4cc，磷化氫（PH3) 之加添量爲每分鐘430cc。然後俟伴隨有該含有硼與磷之 氣體的運載氣體流通於氣相成長爐U內後，即開始單體的 磷化硼層1 〇 2之氣相成長。繼續8分鐘使伴隨有該含有硼 與磷之氣體的運載氣體流通，而以氣相成長了層厚爲300 奈米之單體磷化硼層1 02。經停止對於運載氣體加添含有 硼與磷之氣體而使磷化硼層1 〇 2之氣相成長結束後，停止 載置台12之高頻感應加熱。然後在由上述Ar-H2混合氣體 (Ar之體積分率与83.3)構成之氣氛中下，使載置台12之溫 度降低於室溫附近溫度後，自氣相成長爐1 1抽出載置台 1 2，並取出了矽單晶基板1 0 1。 根據本發明在矽單晶基板1 〇 1表面上所氣相成長的磷化 硼層102之表面，是呈無突起等且無凹空之平坦的面。並 且製得了連續性優越的磷化硼層。 (比較例） 使用上述（實施例）記載之氣相成長爐11，且在預先不在 氣相成長爐11之內壁11a形成含有硼與磷之被膜下，在具 有{ 1 1 1 }結晶面的矽單晶基板之表面，試作了由表面平坦性 優越的單體磷化硼構成之連續膜的氣相成長。換言之，使 含有硼與磷之氣體及運載氣體直接接觸於氣相成長爐11 的內壁1 1 a之狀況下，試作了磷化硼層之氣相成長。 如上述（實施例）所記載，爲期能與預先在氣相成長爐1 1 之內壁1 1 a設有含有硼與磷之被膜之情況作正確對比，在 -23- 1221002 本比較例則使對矽單晶基板上使磷化硼層氣相成長所需氣 相成長條件設定爲完全與上述（實施例）之情況相同。 然在矽單晶基板上卻未形成出具連續性之層磷化硼層， 而成爲略呈球狀之結晶粒互相重疊而成且凹凸顯著的粗糙 磷化硼層。於第4圖展示在本比較例在矽單晶基板1 0 1上 所氣相成長的磷化硼層1 〇 2之剖面示意圖。如第4圖所示 ，略呈球狀之結晶粒1 〇 3並非均勻地成長於矽單晶基板1 0 1 之表面上，而是成長於局部性領域。而且略呈球狀之結晶 粒1 0 3並非互相貼緊而存在，以致在相鄰接的結晶粒1 0 3 之中間，也能看到空隙1 〇 4之存在。 另外若依照使用一般二次離子質譜分析法（SIMS)之深度 方向（層厚方向）元素分析，在矽單晶基板101與磷化硼層 1 〇 2之界面附近的領域，特別是在結晶粒1 0 3未成長的領 域則顯現出以原子濃度計有超過約7x1 018原子/cm3之氧（0) 原子積存著。此與以上述（實施例）所成長磷化硼層與矽單 晶基板之界面附近領域的氧原子濃度相較，則爲高出約一 位數之高濃度。在矽單晶基板1 〇 1表面顯出該氧原子濃度 之顯著差異之分析結果，是在暗示著有無本發明之含有硼 與磷之被膜是與氧原子濃度有關。換言之，例如即使含有 氮（N)等分解生成物不存在於氣相成長爐11之內壁11a， 但就結果而言，是在指點本發明之含有硼與磷之被膜在防 止因來自於由石英材料所構成氣相成長爐1 1之氧的矽單 晶基板表面污染上是有效。 - 24- 1221002 發明之效果 若依照本發明，則在矽單晶基板等基質上以氣相成長手 段使磷化硼系半導體層氣相成長時，由於採取在氣相成長 爐內壁預先形成含有硼與磷之被膜後，才實施氣相成長之 方法，所以能回避矽單晶基板等之基質表面污染，在製造 表面平坦性優越且具連續性之磷化硼系半導體層上能發揮 功效。 (五）圖式簡單說明 第1圖爲顯示依先前技術之矽單晶基板表面之元素分析 結果圖。 第2圖爲顯示依本發明之矽單晶基板表面之元素分析結 果圖。 第3圖爲顯示本發明實施例之氣相成長裝置結構示意圖。 第4圖爲顯示本發明比較例之磷化硼層結構剖面示意圖。 要部分 之代表 符 號 說 明 11 氣 相 成 長 爐 11a 內 壁 12 載 置 台 13 筒 頻 線 圈 14 導 入 □ 15 排 氣 □ 16 熱 電 偶 17 被 膜 10 1 矽 單 晶 基 板 -25- 1221002 102 磷化硼層 10 3 結晶粒 1 04 結晶粒間之空隙 -26-Inst. Phys, Conf. Ser., No. 129 (IPPO pub. Ltd., 1 9 9 3, UK) p. 1 5 7 ~ 162). It is used to make the above-mentioned gas raw materials transport and supply the gas supplied to the gas phase 1221002 growth furnace, and has always used hydrogen (h2) exclusively (see the above Inst. Phys? C ο n f. Νο · 129) ο On the other hand, It is known that the coating of silicon nitride (Si3N4) or silicon dioxide (Si02) existing on the surface of a silicon single crystal substrate is a masking material that can hinder the growth of gallium nitride (GaN) (please (1) J. Crystal Growth, 230 (2001)), pp. 341 to 346, and ② comrades, pp. 3 4 6 to 3 50). Based on these effects, the film of silicon nitride or silicon oxide is effectively used to form a DI group nitride-based semiconductor layer containing nitrogen as a constituent element, and is formed to be limited to an appropriately selected area on the substrate surface. Select the substrate surface coating material required for the growth method (please refer to "m-nitride semiconductors" (February 1, 1999, February 1, 1999, issued by Peifengguan Co., Ltd., first edition, pages 1 2 to 1 2 4). (3) Summary of the Invention The technical problem to be solved by the invention. In the past, the boron phosphide-based semiconductor layer forming technology, such as the above-mentioned BP / GaxAli_xN (0 $ XS 1) superlattice layer, was made by using The crystal layer and the GaxAlhNCO S XS 1) crystal layer are alternately laminated. Since a superlattice layer of a III-group boron phosphide-based semiconductor layer containing such nitrogen is formed in the same vapor-phase growth furnace, the inner wall of the vapor-phase growth furnace or the mounting table must adhere to a crystal containing a III-nitride crystal. Decomposition products. According to the nitrogen constituting the m-type nitride semiconductor layer, it is easy to volatilize at a temperature of about 1,000 ° C or higher, which has been conventionally used for boron phosphide-based semiconductor layers (see J. Phys). Chem ·, 6 9 (1 0) (1 9 6 5), 3, 4 5 5 ~ 3, 4 6 0). Therefore, nitrogen is released into the vapor growth furnace from the decomposition product containing the π-group nitride semiconductor crystal at a temperature-rising stage required to form the boron phosphide-based semiconductor layer 1221002. In particular, the sublimation temperature of indium nitride (ΙηΝ) can be as low as 620 ° C in a vacuum (see "Compound Semiconductor Assembly" (edited by (September 15, issued by (Industry Survey, Inc.), page 397), so the decomposition products containing indium nitride will significantly release nitrogen into the gas phase growth furnace. Part of the nitrogen discharged into the vapor growth furnace at high temperature will react on the surface of the silicon single crystal substrate to form a silicon nitride film. As in the case where the normal formation of the guar nitride semiconductor layer is hindered by the silicon nitride film, the silicon nitride film formed on the surface of the silicon single crystal substrate due to nitrogen existing in the vapor growth furnace, It also hinders the formation of boron phosphide-based semiconductor layers. Therefore, it will be attributed to a boron phosphide-based semiconductor layer with intense unevenness and lack of continuity. A boron phosphide-based semiconductor layer formed on the surface of a silicon single crystal substrate. If it starts to lack surface flatness and continuity, It is impossible to further form a crystalline layer having continuity and excellent surface flatness thereon. If it is desired to construct, for example, a light emitting diode (LED) from such a laminated structure including a discontinuous crystalline layer, it is impossible due to the discontinuity of the crystalline layer or the non-flatness of the p ^ junction interface. An LED having a low forward voltage (so-called Vf) and excellent current characteristics is obtained. Yes * _herein 'The present invention is to solve the above-mentioned problems of the prior art and the purpose of the stomach is to reveal a type of silicon monocrystalline substrate that can inhibit the formation of silicon single crystal substrates. A means for suppressing the emission of substances produced in a growth furnace, thereby providing a vapor phase growth method for forming a boron phosphide-based semiconductor layer with excellent flatness and continuity on the surface of a silicon single crystal 1221002 substrate. Technical means for solving the problem Specifically, the present invention is: (1) A method for vapor phase growth of a boron phosphide-based semiconductor layer, which is a method for vapor phase growth on a silicon (Si) single crystal substrate in a vapor phase growth furnace. The boron phosphide-based semiconductor layer is vapor-grown, and is characterized in that a gas containing boron (B) and phosphorous (P) and a carrier gas accompanying it are circulated in a vapor growth furnace, and After a film containing boron and phosphorus is formed on the inner wall of the vapor growth furnace, a boron phosphide-based semiconductor layer is vapor-grown on a silicon single crystal substrate. (2) The vapor phase growth method of the boron phosphide-based semiconductor layer according to the item (1), wherein the carrier gas is a gas containing 60% or more of argon (Ar) by volume fraction. (3) The vapor phase growth method of the boron phosphide-based semiconductor layer according to the item (1) or (2), wherein the gas containing boron is a gas containing an organic boron compound but not containing a halogen. (4) The vapor phase growth method of the boron phosphide-based semiconductor layer as described in the items (1) to (3), wherein the gas containing phosphorus is a gas containing an organic phosphine compound and not containing a halogen. (5) The vapor phase growth method of the boron phosphide-based semiconductor layer as described in the items (1) to (4), wherein a substrate mounting table on which a silicon single crystal substrate is not placed is arranged inside the vapor phase growth furnace, and the substrate is The stage is maintained at a temperature of 500 ° C to 1200 1 and the gas containing boron (B) and phosphorus (P) -10- 1221002 and the carrier gas accompanying it are allowed to circulate in the gas phase. Inside, a coating film containing boron and phosphorus is formed on the inner wall of the vapor growth furnace. (6) The vapor phase growth method of the boron phosphide-based semiconductor layer as described in the items (1) to (5): After the m-type nitride semiconductor is vapor-phase grown in a vapor-phase growth furnace, the gas phase is grown in the vapor phase. The inner wall of the furnace was formed to contain a blanket L made of boron and phosphorus, and then a boron phosphide-based semiconductor layer was vapor-grown on the surface of the silicon single crystal substrate in the same vapor-growth furnace. (7) The vapor phase growth method of the boron phosphide-based semiconductor layer as described in the items (1) to (6), wherein a quilt containing boron and phosphorus is formed on the inner wall of the vapor phase growth furnace, and the substrate is placed on a substrate. The silicon single crystal substrate is placed on the stage and placed inside the vapor growth furnace, and the temperature of the substrate stage is increased to 25 ° t: above 1,200 ° C, so that the vapor phase of the boron phosphide-based semiconductor layer is grown in Government single crystal substrate surface. (8) A boron phosphide-based semiconductor layer, which is produced by the vapor phase growth method of the scaled boron-based semiconductor layer described in the above (" to (?)). (4) Embodiments of the invention Embodiments In the present invention, regardless of the growth means such as the MOCVD method, the halogen vapor phase growth method, or the hydride vapor phase growth method, a vapor phase growth furnace exists in a decomposition product containing nitrogen (N) or oxygen (0). It is particularly effective when a boron phosphide-based semiconductor layer is vapor-grown on the surface of a silicon single crystal substrate inside. Therefore, the substrate can have a {1 0 0} crystal plane, a {1 1 〇} crystal plane, or {1 1 1} A silicon single crystal (silicon) having a crystal surface. A sand single crystal having a crystal surface inclined toward a specific crystal direction as a surface can also be used as a substrate. For example, it can be crystallized to < ii 〇 > -11- 1221002 The silicon single crystal with the {1 ο ο} crystal plane whose direction is inclined by about 7 degrees (°) as the angle is used as a substrate. If a silicon single crystal of η-type or P-type conductivity is used as the substrate, The back of the substrate is provided with an ohmic (0 hmic) electrode of either polarity, Therefore, it is convenient to construct light-emitting elements, light-receiving elements, etc. Especially for conductive single crystal substrates with low specific resistance (= resistivity) having a resistivity of 1 milliohm or less, more preferably 0.1 Ω or less, It will help to produce LEDs with low forward voltage (so-called Vf). In addition, it is effective for forming LDs that can provide stable oscillation due to its excellent heat dissipation properties. Boron phosphide system provided on the surface of silicon single crystal substrate The semiconductor layer is formed by using boron and phosphorus as constituent elements and containing, for example, BAAlBGacIiiDPidAw (〇 < Α $ 1, 〇gB < 1, 0SC < 1, 0SD < 1, A + B + C + D = 1, OS δ & lt 1) a layer composed of, or, for example, BAAlBGacIriDPHN ^ fX AS 1, 0 $ B < 1, 0gC < l, 0 ^ D < 1 'A + B + C + D = 1, 0 ^ δ < 1 ) The layer of composition. The present invention can be applied regardless of the configuration of the boron phosphide-based semiconductor layer provided on the surface of the silicon single crystal substrate, that is, whether it is amorphous, polycrystalline, or monocrystalline '. In addition, regardless of the conductivity type of the boron phosphide-based semiconductor layer, or the type of dopant intentionally added to control the conductivity type, the carrier gas concentration, and the layer thickness, the present invention can be used. efficacy. Furthermore, the present invention is not limited to the case where the boron phosphide-based semiconductor layer is bonded to the surface of a sand single crystal substrate and the gas phase is grown, and in particular, a nitrogen (N) -containing, for example, m-group nitride semiconductor layer is used as a gas. The phase grower also functions when a boron phosphide-based semiconductor layer is bonded to the same layer in the same vapor phase growth furnace. In the first embodiment of the present invention, before the substrate is placed on the mounting table as described above with a silicon-12-1221002 single crystal substrate: before the substrate is formed, it is covered with a film containing boron and phosphorus. Or the inner wall of a gas phase growth furnace made of ceramic materials such as boron nitride (BN). The inner wall of the vapor-phase growth furnace refers to the wall surface of the inner surface of the member closest to the substrate and disposed around the substrate and facing the substrate. The film is specifically made of boron and _ at a temperature of 5,000t or more and 1,200 or less while maintaining a mounting table made of a temperature-resistant material such as graphite or silicon carbide (S i C). The gas and the carrier gas accompanying it are formed in a vapor growth furnace. Thereby, a film containing a decomposition product of nitrogen (N) attached to the inner wall of the vapor growth furnace is covered. As the boron-containing gas, triethylboron [(C2H5) 3B], borane (Bh3), or diborane (Β2ίί6) 'can be used. Phosphine (ph3) can be used as the gas containing phosphorus. In order to form a film containing boron and phosphorus in the inner wall of the gas phase growth furnace and to pass the phosphorus atom concentration in the gas phase growth furnace, it is preferable to set the concentration exceeding the boron atom concentration. For example, it is preferable to supply phosphorus atoms having a concentration of boron atom 'of about 5 times or more, preferably 10 times or more, to a vapor growth furnace. When the phosphorus atom concentration does not exceed the boron atom concentration when the film is formed, when a boron phosphide-based semiconductor layer is actually formed, phosphorus is easily absorbed by a film containing a rich m-group constituent element such as boron, so it cannot be stabilized. The problem of obtaining a boron phosphide-based semiconductor layer that is stoichiometrically balanced and has an excellent equivalent ratio. The mounting table is heated by a method such as a high-frequency heating method, a resistance electrification method, or an infrared heating method. The purpose of heating the mounting table is to thermally decompose a boron and phosphorus-containing gas supplied to a gas-phase growth furnace to generate boron and phosphorus for forming a film. Although a special heating device attached to the gas-phase growth furnace can be used to thermally decompose boron and phosphorus-containing gas, '-13-1221002 can be directly heated and placed on the mounting table of the gas-phase growth furnace. It can be easily thermally decomposed. Generally, it is not possible to sufficiently thermally decompose a gas containing boron and phosphorus at a low temperature of less than about 25 ° C. Therefore, it is not convenient to effectively attach a film containing boron and phosphorus to the inner wall of a vapor growth furnace. In order to effectively form a film containing boron and phosphorus, the temperature of the mounting table should be above 500 ° C, so as to promote the thermal decomposition of the gas containing boron and phosphorus. On the contrary, when it exceeds 1,200 ° C At high temperatures, the highly volatile Group V elements such as phosphorus will evaporate. As a result, the formed group will be attributed to a film rich in Group M elements, and the boron phosphide-based semiconductor layer with a balanced composition will be produced. It will cause obstacles. It is preferable to set the temperature of the mounting table to a high temperature so that the phosphorus-containing gas is in a temperature range suitable for the formation of the film at a temperature of 50 ° C or more and 1,200 ° C or less. The supply in the gas-growth furnace is increased relative to the supply of boron-containing gas. This is to consider that phosphorus will be emitted in a high-temperature environment and to avoid adhesion of the HI group element-rich coating in the gas-growth furnace The reason for the wall. It can form a film containing boron and phosphorus that can sufficiently cover the surface of decomposition products containing nitrogen (N), etc. The film thickness of the film containing boron and phosphorus should be greater than the decomposition products containing nitrogen (N), etc. The average thickness is about twice or more, and more preferably about four times or more. If the film is a thick film, it is easy to peel off from the inner wall of the vapor phase growth furnace. Therefore, during the vapor phase growth of the boron phosphide-based semiconductor layer, phosphating The surface state of the boron-based semiconductor layer will be damaged by peeling off from the inner wall of the vapor growth furnace and flying to the small piece of film attached to the surface of the silicon single crystal substrate. Therefore, the film thickness of the film should be within about ten times the average thickness of the decomposition product. The thickness of the coating film can be adjusted by controlling the flow time of the gas containing boron and phosphorus in the gas phase 1221002 growth furnace when the mounting table is heated. Or, in a certain flow time, especially the When the supply amount (= concentration) of boron gas is adjusted to a larger amount, a film having a larger film thickness can be obtained. In the second embodiment of the present invention, when forming a film containing boron and phosphorus, argon ( Ar) as the main body Method for carrying a gas containing these elements in a gas phase growth furnace. Therefore, the carrier gas will be supplied into the gas phase growth furnace together with a gas containing boron and phosphorus to form an atmosphere in the gas phase growth furnace. In other words, the second embodiment of the present invention is characterized in that a film containing boron and phosphorus is formed under an atmosphere containing argon as the main body. The so-called main body is one containing 60% or more of argon by volume fraction. Example Note that there are argon monomer (volume fraction of argon = 100%), mixed gas of argon (volume fraction = 70%) and hydrogen (H2) (volume fraction = 30%), etc. Argon volume fraction It can be expressed in terms of the volume fraction of argon in the total gas volume. For the purpose of the present invention, which is to suppress the concentration of nitrogen (N) or oxygen (0) released in a gas phase growth furnace, argon and nitrogen (N 2), argon and ammonia (NH3), or argon and oxygen (〇2) and other mixed gas of argon and nitrogen-containing gas or oxygen-containing gas can not be used. This may cause a problem of forming a mas king film made of silicon nitride or silicon oxide on the surface of a silicon single crystal substrate. This masking film hinders normal vapor phase growth of the boron phosphide-based semiconductor layer. For example, in a mixed gas of argon and hydrogen, the volume fraction of argon can be changed by adjusting the argon flow rate relative to the total flow rate of argon and hydrogen per unit time. For example, in a mixed gas of argon and hydrogen, when the volume fraction of argon becomes 60% or less, hydrogen will combine with the phosphorus contained in the film to become a high-vapor-pressure phosphine and detach, which will cause the film to suddenly be significantly affected. erosion. Due to this, the thickness of the coating film will be reduced ', so that the surface of the decomposition product containing nitrogen and the like cannot be sufficiently covered, and -15-1221002 causes a problem that nitrogen and the like are released into the vapor growth furnace. Although helium (He) or neon (Ne), which is an inert gas of the same family as argon, can also be used as a carrier gas, from an economic point of view, it is most suitable for forming a film containing boron and phosphorus and is composed of an inert gas. The carrier gas is also a gas composed of argon monomer (volume fraction of argon = 100%). In the third embodiment of the present invention, when a film containing boron and phosphorus is formed, a non-halide compound containing no halogen such as chlorine (C1) or bromine (Br) is used as the gas containing boron. In particular, halogen-free organic boron compounds such as trimethylboron [(CH3) 3B] and triethylboron [(C2H5) 3B] are used. This can avoid the phenomenon of film corrosion caused by halogen radicals or halogen gases generated during the thermal decomposition of halogen-containing borides. Among the boron aliphatic saturated compounds, triethyl boron has a moderate vapor pressure at normal temperature, so it is convenient to appropriately adjust the flow rate ratio to the phosphorus-containing gas flowing in the gas-phase growth furnace. In addition, an organic boron compound having a functional group containing a nitrogen (N) atom or an oxygen (0) atom cannot be used for forming a film. Since the formation of a film containing nitrogen (N) or oxygen (0) is guided, it constitutes a source of nitrogen or oxygen emission in a vapor growth furnace. In the fourth embodiment of the present invention, when a film containing boron and phosphorus is formed, a non-halogen compound containing no halogen such as chlorine (C1) or bromine (Br) is used for the gas containing phosphorus. In particular, halogen-free hydrides such as phosphine (P Η 3) are used. Phosphorous halide compounds containing halogens cannot be used because they generate halogens during thermal decomposition and erode the film, making it thinner and making the film on the surface of the decomposition product incomplete. In addition, although phosphine exhibits Lewis basic properties, it does not cause significant chemical reaction (ρ 0 1 0 mer) with Lewis acidic compounds such as trimethylboron or triethylboron. It has the advantage that -16-1221002 can be sent to the gas phase growth furnace at the desired concentration without causing unnecessary waste due to the reaction. Hydrogenates of phosphorus containing nitrogen (N) atoms or oxygen (0) atoms other than hydrogen cannot be used for film formation. Since the formation of a film containing nitrogen (N) or oxygen (0) is guided, a source of nitrogen or oxygen is formed in the vapor growth furnace. When phosphine is used as a phosphorus-containing gas, hydrogen (H2) is generated in the gas-phase growth furnace according to the following chemical reaction formula (1) due to thermal decomposition. PH3 — P + 3/2 · Η2 Chemical reaction formula (1) In other words, chemical reaction formula (1) means that if 1 mol. Of PZ3 is completely thermally decomposed, 1.5 mol of hydrogen will be generated. Therefore, if the above-mentioned mixed gas of argon and hydrogen is used as the carrier gas, it is necessary to set the volume fraction of argon to hydrogen gas generated by thermal decomposition of argon, hydrogen, and phosphine that constitute the mixed gas. The total volume is over 60%. The amount of hydrogen produced by the thermal decomposition of phosphine should generally be estimated as the amount produced by the complete thermal decomposition of (PH3) (1.5 mol of hydrogen per PH3 of PH3). After forming a film containing boron and phosphorus on the inner wall of the vapor-phase growth furnace, the temperature of the mounting table is lowered to a temperature near room temperature, for example, so that a silicon single crystal is placed on the mounting table as a substrate. Then, the silicon single crystal is placed in a predetermined position on a mounting table cooled to a temperature at which the substrate can be placed, and then the mounting table is placed in a specific position in the gas phase growth furnace with the substrate placed. The specific position herein refers to a position in a vapor-phase growth furnace that is convenient for uniformly heating to a temperature necessary for vapor-phase growth of a boron phosphide-based semiconductor layer. Then, the stage temperature was raised to a temperature suitable for vapor phase growth of the boron phosphide-based semiconductor layer. For vapor phase growth of a boron phosphide-based semiconductor layer on a silicon single crystal substrate, you can grow it by M OCVD method, halogen vapor phase growth method, hydride vapor phase growth method, or gas source molecular beam Jiajing. (See Solid Stated Chem., 133 (1997), pp. 269 to 272). In order to make vapor-phase growth of an amorphous or polycrystalline boron-based semiconductor layer, a temperature of 25 (TC ~ 750 ° C) is suitable. For the vapor phase of a single-crystal boron-based semiconductor layer For growth, a temperature of 750 ° C to 1,200 ° C is suitable. Above 1,20 ° C (high temperature, polymer boron phosphide such as B6P or B13P2 will be formed, so it is not convenient to use Boron phosphide-based semiconductor layer with uniform vapor phase growth composition. The temperature of the mounting table can be measured or adjusted by using temperature measuring instruments such as thermocouples and radiation thermometers. To increase the temperature of the mounting table and thus the silicon single crystal placed on the mounting table When the substrate temperature is raised to a temperature suitable for vapor-phase growth of the boron phosphide-based semiconductor layer, the atmosphere in the vapor-phase growth furnace is mixed with an inert gas such as argon at a volume fraction of 60% or more. It is suitable to use gas. However, it is most suitable to use argon monomer (volume fraction = 100%). Although the heating method generally used in the hydrogen atmosphere in the past is also feasible, it is performed at the beginning of the boron phosphide-based semiconductor layer. Before the vapor phase growth, the The film with boron and phosphorus will react with hydrogen and cause the bad result of the reduction of the film thickness, so it is not convenient to use. Here is an example to show that the film containing boron and saucer can be formed in advance in gas according to the embodiment of the present invention. The results of the analysis of the effects exhibited in the phase growth furnace are as follows. The samples used for the analysis were gallium chloride-indium mixed crystals (G a 0.90) with a layer thickness of 6 2 0 nm in accordance with the M CVD method. I n Q "G Ν) layer is used for vapor phase growth, and a gas phase growth furnace with an average layer thickness of about 100 nanometers weakly adhered on the inner wall of the gas phase growth furnace, especially around the mounting table, is used. 1221002 First illustrated in Figure 1 according to the prior art, that is, a silicon single crystal substrate having a {111} crystal plane is heated to 1 under a film containing boron and phosphorus before the inner wall of the vapor growth furnace is formed. Result of element analysis on the surface of the substrate after 0 5 0 t. The substrate surface after heating 'although it cannot be clearly seen that a thin film is formed', but according to Auger electron energy spectroscopy (AES), as shown in Figure 1 As shown in the spectrum, in addition to nitrogen (N), carbon is also recognized ( C) and the presence of oxygen (〇). It is thus known that if a silicon single crystal substrate mainly polluted by nitrogen is used, a boron phosphide-based semiconductor layer having continuity and excellent surface flatness can be used as a gas. Phase growth is difficult. Therefore, it is usually only possible to produce boron phosphide-based semiconductor layers that can be attributed to the disorderly stacking of spherical crystals with rough surfaces. Next, the present invention is illustrated in FIG. After forming a coating containing boron and phosphorus on the inner wall of the vapor-phase growth furnace in advance and having a thickness of about 300 nm, a silicon single crystal substrate having a {1 11} crystal plane was applied at 1,050 ° C. Element analysis results of the surface of the substrate after the pre-heat treatment. From the AES spectrum shown in Figure 2, it can be seen that in addition to the AES signal of silicon (Si) from the silicon single crystal of the substrate, it can also be seen that it is minute and originates from carbon. (C) AES signal. In addition, the AES signal of boron and phosphorus from the film containing boron and phosphorus can also be seen. The boron or phosphorus existing on the surface of the silicon single crystal substrate provides the "growth nuclei" required for the growth of the boron phosphide-based semiconductor layer, and is therefore effective for smooth vapor phase growth of the boron phosphide-based semiconductor layer. Therefore, the film according to the present invention has the effect of preventing the surface contamination of the silicon single crystal substrate caused by nitrogen (N) and oxygen (0) originating from the decomposition products adhered to the inner wall of the vapor-phase growth furnace, which is very clear. This kind of nitrogen (N) and oxygen (0) surface pollution prevention effect of the coating according to the present invention, for example, after the m-type nitride semiconductor layer is vapor-grown, the boron phosphide-19-1221002 series semiconductor layer is vapor-phased. Visible as you grow up. However, in this case, after completion of vapor phase growth of a layer containing nitrogen, such as a m-type nitride semiconductor layer, it is necessary to form a film containing boron and phosphorus in advance before performing vapor phase growth of a boron phosphide-based semiconductor layer. . Before the vapor phase growth of the boron phosphide-based semiconductor layer, the film formed on the inner wall of the vapor phase growth furnace and containing boron and phosphorus can prevent the origin of the boron phosphide-based semiconductor layer from hindering the normal growth of the vapor phase. Contamination of the substrate surface that decomposes the φ product in the growth furnace. Before the vapor phase growth of the boron phosphide-based semiconductor layer, a carrier gas containing 60% or more of argon by volume fraction is used to form a film containing boron and phosphorus on the inner wall of the vapor growth furnace. It can create an argon-containing atmosphere in a gas phase growth furnace, and has the effect of suppressing the reduction of the film thickness of the above-mentioned film. Prior to the vapor phase growth of boron phosphide-based semiconductor layers, organic boron compounds that are non-halogen compounds used to form a film containing boron and phosphorus on the inner wall of the vapor growth furnace can be supplied due to thermal decomposition. The boron that constitutes the film has the effect of avoiding a reduction in the film thickness of the formed film. Prior to the vapor phase growth of boron phosphide-based semiconductor layers, organic boron compounds that are non-halogen compounds used to form a film containing boron and phosphorus on the inner wall of the vapor growth furnace can be supplied due to thermal decomposition. The boron constituting the film has the effect of avoiding a reduction in the film thickness of the formed film. Examples (Examples) ~ The monomer boron phosphide (b ο ο η -20-1221002 m ο η 〇ph 〇sphide) is directly grown in the vapor phase with p added with boron by the M CVD method. The case of the surface of a silicon single crystal substrate with a type {1 1 1} crystal surface is taken as an example, and the content of the present invention will be specifically described as follows. FIG. 3 shows a model structure of the MV C V D vapor phase growth device used in this embodiment. The vapor-phase growth apparatus shown in Fig. 3 includes a vapor-growth furnace 11 composed of a high-purity quartz tube used in the semiconductor industry. A cylindrical stage 12 made of high-purity graphite on which a substrate is placed is arranged substantially at the center of the circular gas-phase growth furnace 11. Placed on the outer periphery of the vapor-phase growth furnace 11 around the mounting table 12 An introduction port 14 is provided at one end of the vapor-phase growth furnace 11 for supplying a boron and phosphorus-containing gas and a carrier used for the formation of a film containing boron and phosphorus or the vapor phase growth of a boron phosphide layer into the furnace. gas. In addition, an exhaust port 15 is provided at the other end of the gas phase growth furnace Π so that the gas circulating around the mounting table 12 along the inner wall 11a of the gas phase growth furnace 11 is discharged outside the furnace together with the carrier gas. When the film of the present invention is to be formed, first, argon is used as a carrier gas and supplied to the inside of the vapor phase growth furnace 1 1 φ at a flow rate of 12 liters per minute through the inlet 14. After about 20 minutes have passed since the start of the flow of argon, the high-frequency coil 13 is turned on with a high-frequency power source, and the temperature of the mounting table 12 on which the silicon single crystal substrate is not placed is raised from room temperature to 90 ° C. Then, after confirming that the temperature detected by the thermocouple 16 inserted in the mounting table 12 became stable, the triethylboron [(C2H5) 3B] and phosphine (PH3) together with the inlet 14 were introduced. The carrier gas having the above-mentioned flow rate is supplied into the vapor phase growth furnace 11. The supply of triethylboron is set to about 4cc per minute with a flow meter, and the flow rate of phosphine is set to about 2 0 cc per minute. In this way, the internal pressure of the gas-growth furnace 1 1 is maintained at 1221002. At approximately atmospheric pressure, triethylboron [(c2h5) 3b] and phosphine (ph3) are continuously supplied to the gas-growth furnace 1 1 6 0 Minutes, the boron and phosphorus containing film 17 having a film thickness of about 400 nanometers was formed on the inner wall 1 1 a of the vapor-phase growth furnace 11. As the gas containing boron and phosphorus is a gas containing an organic boron compound and a phosphine compound which are non-halogen compounds, it will not be significantly etched, and its film thickness is equivalent to the supply of triethylboron [(C2H5) 3B ] And the time of phosphine (PH3) increased approximately proportionally. Then, the supply of triethylboron [(C 2 Η 5) 3 B] and phosphine (P 3) to the inside of the gas phase growth furnace 11 1 is stopped. For the inside of the furnace, only the argon gas as a carrier gas is introduced through the introduction port 14. Supply continues at the above flow. Then, the high-frequency induction heating of the mounting table 12 is stopped to reduce the temperature of the mounting table 12. After the temperature is lowered, the mounting table 12 is temporarily taken out of the furnace from the gas-phase growth furnace 11 and the above-mentioned silicon single crystal having a P-type {1 1 1} crystal surface is placed on the central portion of the upper surface of the mounting table 12. The substrate was used as the substrate 101. Thereafter, the mounting table 12 on which the substrate 101 is placed is inserted again at a specific position of the vapor growth furnace 11. After the insertion, argon gas is supplied from the inlet 14 at a rate of 12 liters per minute inside the vapor-phase growth furnace 11. After that, the temperature of the mounting table 12 was raised to 8 5 ° C. by a high-frequency induction heating means in an atmosphere made of argon. After the temperature of the mounting table 12 reached 8 5 ° C., a boron phosphide layer was applied. Before the growth of the gas phase, reduce the flow rate of argon as a carrier gas from 12 liters per minute to 10 liters per minute. At the same time, add 2 liters of hydrogen per minute to argon, and re-use argon The volume fraction of about 8.3% of the Ar Η Η 2 mixed gas is used as a carrier gas. After the Ar-H2 mixed gas is temporarily circulated inside the gas phase growth furnace 11, -22- 1221002 is Triethyl boron [(c2h5) 3b] and phosphine (ph3) are added to the mixed gas. The addition amount of triethyl boron [(C2H5) 3B] is 4cc per minute, and phosphine (PH3) The addition amount is 430cc per minute. Then, after the carrier gas accompanied by the gas containing boron and phosphorus is circulated in the vapor phase growth furnace U, the vapor phase growth of the single boron phosphide layer 100 is started. Continue The carrier gas accompanied by the gas containing boron and phosphorus was circulated for 8 minutes, and the monomer phosphorylation with a layer thickness of 300 nm was grown in the gas phase. Layer 102. After the gas phase growth of the boron phosphide layer 102 has been stopped by adding a gas containing boron and phosphorus to the carrier gas, the high-frequency induction heating of the mounting table 12 is stopped. Then, the above-mentioned Ar-H2 In an atmosphere composed of a mixed gas (volume fraction of Ar and 83.3), the temperature of the mounting table 12 is lowered to a temperature near room temperature, and then the mounting table 12 is pulled out from the gas phase growth furnace 11 and the silicon single crystal is taken out. Substrate 1 0. According to the present invention, the surface of the boron phosphide layer 102 vapor-grown on the surface of the silicon single crystal substrate 100 is a flat surface having no protrusions and no recesses, and continuity is obtained. (Comparative example) The vapor phase growth furnace 11 described in the above (Example) was used, and a film containing boron and phosphorus was formed on the inner wall 11a of the vapor phase growth furnace 11 not in advance. 1 1 1} On the surface of a silicon single crystal substrate with a crystalline surface, a vapor phase growth of a continuous film composed of a single boron phosphide with excellent surface flatness was attempted. In other words, a gas containing a boron, a phosphorus gas, and a carrier gas were brought into direct contact. In the condition of the inner wall 1 1 a of the gas phase growth furnace 11, try The vapor phase growth of the boron phosphide layer is described. As described in the above (example), it is possible to make a correct comparison with the case where a film containing boron and phosphorus is provided on the inner wall 1 1 a of the vapor growth furnace 1 1 in advance. In -23-1221002, in this comparative example, the vapor phase growth conditions required for vapor phase growth of a boron phosphide layer on a silicon single crystal substrate are set to be completely the same as those in the above-mentioned (example). However, a continuous boron phosphide layer is not formed on it, but a rough boron phosphide layer formed by overlapping slightly spherical crystal grains with each other and having significant unevenness. As shown in FIG. 4, a silicon single crystal is shown in this comparative example in FIG. 4. A schematic cross-sectional view of a boron phosphide layer 100 that is vapor-grown on a substrate 101. As shown in FIG. 4, the slightly spherical crystal grains 103 do not grow uniformly on the surface of the silicon single crystal substrate 101, but grow in localized areas. Moreover, the slightly spherical crystalline particles 103 do not exist close to each other, so that the existence of the void 104 can be seen in the middle of the adjacent crystalline particles 103. In addition, in accordance with elemental analysis in the depth direction (layer thickness direction) using general secondary ion mass spectrometry (SIMS), in the vicinity of the interface between the silicon single crystal substrate 101 and the boron phosphide layer 10, especially in the crystal grains In the field of 103 that has not grown, oxygen (0) atoms in excess of about 7x1 018 atoms / cm3 in terms of atomic concentration are accumulated. Compared with the concentration of oxygen atoms in the vicinity of the interface between the boron phosphide layer and the silicon single crystal substrate grown in the above-mentioned (Example), the concentration is higher by about a single digit. The analysis result showing a significant difference in the oxygen atom concentration on the surface of the silicon single crystal substrate 101 indicates that the presence of the boron and phosphorus-containing film of the present invention is related to the oxygen atom concentration. In other words, for example, even if a decomposition product containing nitrogen (N) does not exist on the inner wall 11a of the vapor growth furnace 11, as a result, it is intended to point out that the film containing boron and phosphorus of the present invention prevents The surface contamination of the silicon single crystal substrate of oxygen of the vapor phase growth furnace 11 made of quartz material is effective. -24- 1221002 Effect of the Invention According to the present invention, when a boron phosphide-based semiconductor layer is vapor-phase grown by a vapor-phase growth method on a substrate such as a silicon single crystal substrate, it is formed in advance on the inner wall of the vapor-phase growth furnace. The method of vapor phase growth is carried out only after the coating of boron and phosphorus, so that the surface contamination of the substrate such as a silicon single crystal substrate can be avoided, and the boron phosphide-based semiconductor layer with excellent surface flatness and continuity can be used. (V) Brief Description of the Drawings Figure 1 is a diagram showing the results of elemental analysis on the surface of a silicon single crystal substrate according to the prior art. Figure 2 is a graph showing the results of elemental analysis on the surface of a silicon single crystal substrate according to the present invention. FIG. 3 is a schematic diagram showing a structure of a vapor phase growth apparatus according to an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a structure of a boron phosphide layer according to a comparative example of the present invention. Description of the main symbols of the main parts 11 Inner wall of gas-growth furnace 11a 12 Mounting table 13 Barrel coil 14 Introduction □ 15 Exhaust □ 16 Thermocouple 17 Coating 10 1 Silicon single crystal substrate-25- 1221002 102 Boron phosphide layer 10 3 Crystal grains 1 04 Gap between crystal grains 26-