1251947 九、發明說明： 【發明所屬之技術領域】 本發明是有關於一種可發光的固態半導體元件，特別 是指一種具有多重量子井結構（Multiple Quantum Well ;簡 稱MQW)的半導體發光元件，例如發光二極體（Light Emitting Diode;簡稱 LED)和半導體雷射（Laser Diode;簡 稱LD)等。 【先前技術】 參閱圖1，一般的氮化鎵系發光二極體元件如圖所示的 包含一藍寶石基板91 ’ 一氮化錄缓衝層9 2、一未捧雜之氮 化鎵層93、一 η型披覆層94、一發光單元95、一 p型彼覆 層96，及一對電極97。該發光單元95如圖2所示的包括 有複數交錯排列的阻障層95 1和井層952，及一兩側分別連 接最上方阻障層95 Γ和該ρ型披覆層96的包覆層95 3。 該η型披覆層94和ρ型彼覆層96之主要材質為氮化 鎵（GaN)，該阻障層95 1之材質為氮化鋁銦鎵（AlInGaN)，該 井層952之材質為氮化銦鎵（InGaN)，該包覆層953之材質 為鋁摻雜之氮化鎵AlGaN。對電極97施以一適當之直流壓 差，即可使發光單元95可產生光，例如美國專利第 6,586,762號發明專利即揭示此種具有多數所述的阻障層 951和井層952的發光二極體元件。 但是，此種發光二極體元件中，由於阻障層951、井層 952和包覆層953材質的晶格常數不匹配（lattice mismatch) ，以及熱膨脹係數（thermal expansion cofficient)不同，因此 1251947 ，在其介面處容易產生缺陷（defect)而造成發光單元95的品 貝（quality)不佳’導致發光效率（Ught extraction efficiency) 低落。 【發明内容】 口此本發明之目的，即在提供一種具有良好結晶品 質和高發光效率的發光二極體元件。 於是’本發明氮化鎵系發光二極體元件包含一基材， 一形成於該基材上的n型氮化鎵系半導體層、一形成於該η 3L氮化鎵系半導體層上的發光單元，和一形成於該發光單 元上的P型氮化鎵系半導體層。 該基材具有一選自於由下列材料所構成之基板的群組 •藍貲石、碳化矽，和矽；該基材更具有一於該基板上成 長有氮化鎵基礎（galllum nitdde based)材料所構成之緩衝層 垓η型氮化鎵系半導體層和p型氮化鎵系半導體層之1251947 IX. Description of the Invention: [Technical Field] The present invention relates to a luminescent solid-state semiconductor device, and more particularly to a semiconductor light-emitting device having a multiple quantum well structure (MQW), such as luminescence Light Emitting Diode (LED) and Laser Diode (LD). [Prior Art] Referring to FIG. 1, a general gallium nitride-based light-emitting diode element includes a sapphire substrate 91' as shown in the figure, a nitride buffer layer 9.2, and an un-doped gallium nitride layer 93. An n-type cladding layer 94, a light-emitting unit 95, a p-type cladding layer 96, and a pair of electrodes 97. The light-emitting unit 95 includes a barrier layer 95 1 and a well layer 952 which are arranged in a plurality of staggered manners as shown in FIG. 2 , and a coating on which the uppermost barrier layer 95 Γ and the p-type cladding layer 96 are respectively connected on both sides. Layer 95 3. The main material of the n-type cladding layer 94 and the p-type cladding layer 96 is gallium nitride (GaN), and the material of the barrier layer 95 1 is aluminum indium gallium nitride (AlInGaN), and the material of the well layer 952 is Indium gallium nitride (InGaN), the cladding layer 953 is made of aluminum-doped gallium nitride AlGaN. Applying a suitable DC voltage difference to the electrode 97 allows the illumination unit 95 to generate light. For example, the invention patent of U.S. Patent No. 6,586,762 discloses the illumination of the barrier layer 951 and the well layer 952. Polar body component. However, in such a light-emitting diode element, since the lattice constant mismatch of the barrier layer 951, the well layer 952 and the cladding layer 953, and the thermal expansion cofficient are different, 1251947, A defect is easily generated at the interface thereof to cause a poor quality of the light-emitting unit 95, resulting in a decrease in Ught extraction efficiency. SUMMARY OF THE INVENTION The object of the present invention is to provide a light-emitting diode element having a good crystalline quality and high luminous efficiency. Thus, the gallium nitride-based light-emitting diode device of the present invention comprises a substrate, an n-type gallium nitride-based semiconductor layer formed on the substrate, and a light-emitting layer formed on the η 3L gallium nitride-based semiconductor layer. And a P-type gallium nitride based semiconductor layer formed on the light emitting unit. The substrate has a group selected from the group consisting of: blue ochre, tantalum carbide, and tantalum; the substrate further has a gallium nitride base grown on the substrate (galllum nitdde based) a buffer layer composed of a material, a 垓n-type gallium nitride-based semiconductor layer, and a p-type gallium nitride-based semiconductor layer
材貝的化學式為AlxInyGai_”N，且匕乂以，& 1 -x-y〉〇 〇 钱贫无皁元具有至少 y ，曰，王^ 一开潛，及一最 ，阻障層。其中，該阻障層與該井層是彼此交錯排列，該 取後阻障層之兩相反側分別與該p型氮化㈣半導體層和 該井層連接，而該阻障層之兩相反側分別與該n型氮切 糸半導體層和該井層連接。該阻障層的材質為Aun n)N，且 工，〇< ( m' T ~ =n==1。該井層的材質為 咖㈣N的材料所製成，且〇<k<i ;較佳地該阻障層的 6 1251947 厚度大於該井層。 • 该取後阻障層的能隙，較佳地小於該P型氮化鎵系半 導體層’更佳地應大於該井層的能隙。該最後阻障層，較 佳地由化學式為InjGa(H)N的材料所製成，其中」值較佳 地小於0.5，更佳地大於或等於〇 〇1且小於或等於ο」。該 最後阻障層的厚度，較佳地大於該井層，更佳地小於該p 型虱化鎵系半導體層，且其厚度較佳地大於或等於5〇人，且 • 小於或等I 500A。該井層較佳地具有量子點（quantum d〇t) < 結構。 【實施方式】 有關本發明之前述及其他技術内容、特點與功效，在 乂下配a參考圖式之較佳實施例的詳細說明中，將可清楚 的呈現。 茶閱圖3、4 ’本發明氮化鎵系發光二極體元件的較佳 二轭例包含一基材丨、一形成於該基材丨上的n型氮化鎵系 藝半導體層2、一形成於該n型氮化鎵系半導體層2上的發光 單元3、一形成於該發光單元3上的p型氮化鎵系半導體層 4，及二分別形成於該η型氮化鎵系半導體層2和該p型氮 化鎵系半導體層4的電極5。 該基材是一由藍寶石基板11、氮化鎵緩衝層12和一未 摻雜之氮化鎵層13所構成之三明治結構，其是以金屬有機 化+氣相沈積法（metal_organic chemicai vap〇r deposition; 簡稱MOCVD)來製成。需說明的是，在以下的敘述說明中 ’各半導體磊晶層皆是以金屬有機化學氣相沈積法來製成 7 1251947 ，但也可以利用如分子束蟲晶法（M〇lecuiar Be㈣邮吻； 簡稱MBE)等習知之磊晶成長方法。 "该η型氮化鎵系半導體層2的主要材質為氮化錄（灿) ’並摻雜冑WW的矽而形《n型半導體，其厚度為 3000 nm 〇 省1光單元3具有複數彼此交錯排列的阻障層3 1和井 層32;其中，最下方的阻障層31，連接該打型氮化嫁系半導 Μ 2,而最上方的井層32，則與該最後阻障層33連接，且 该最後阻障層33相反於最上方的井層32，的—側與該ρ型 氮化鎵系半導體層4相連接。 制上述的阻障層31是以化學式Un〇.〇3Ga"7N的材料所 製成，其厚度為20 nm。上述的井層32是以化學式為 In^Ga0.8N的材料所製成，且井層32具有量子點結構，而 其厚度為2 nm。上述的最後阻障層33以化學式為 InowGaowN的材料所製成，其厚度為3〇〇A。 4 P型氮化錁系半導體層4，其主要材質為氮化鎵 (GaN)，並摻雜有2xl〇18cm-3的鎂而形成p型半導體，其厚 度為15 0 nm。 圖5說明了本發明較佳實施例之發光單元3相對於η 型、Ρ型氮化鎵系半導體的能階示意圖。D2表示該η型氮化 鎵系,導體層2的能隙’ D31表示該阻障層31的能隙鳴2 表不。亥井層32的能隙，D33表示該最後阻障層33的能隙， D4表示該ρ型氮化鎵系半導體層4的能隙。由圖可知該最 後阻障層的能隙D33小於該p型氮化鎵系半導體層*的能隙 1251947 〇4，且大於該井層32的能隙Du，因此可增加在p型氮化 鎵系半導體層4中的電洞進入發光單元3的機率，進而提 昇發光效率。 參閱圖6之亮度電流曲線（Iv-I curve)比較圖，，圖中虛 線指出習知氮化鎵系發光二極體元件的亮度電流曲線，而The chemical formula of the shellfish is AlxInyGai_"N, and the & 1 -xy> is rich in soap-free elements with at least y, 曰, Wang ^ a dive, and a most, barrier layer. The barrier layer and the well layer are staggered with each other, and the opposite sides of the barrier layer are respectively connected to the p-type nitride (tetra) semiconductor layer and the well layer, and the opposite sides of the barrier layer respectively The n-type nitrogen-cut tantalum semiconductor layer is connected to the well layer. The material of the barrier layer is Aun n)N, and the work, 〇 < ( m' T ~ = n==1. The material of the well layer is coffee (four) N The material is made of 〇<k<i; preferably, the barrier layer has a thickness greater than that of the well layer. • The energy gap of the rear barrier layer is preferably smaller than the P-type nitride. The gallium-based semiconductor layer 'should be better than the energy gap of the well layer. The final barrier layer is preferably made of a material of the formula InjGa(H)N, wherein the value is preferably less than 0.5, more Preferably, the thickness of the last barrier layer is greater than the well layer, more preferably smaller than the p-type gallium germanide-based semiconductor layer, and Preferably, the degree is greater than or equal to 5 ,, and • is less than or equal to I 500 A. The well layer preferably has a quantum dot structure. [Embodiment] The foregoing and other techniques related to the present invention The contents, features and effects will be clearly shown in the detailed description of the preferred embodiment of the reference frame. Fig. 3, 4 'Compare of the gallium nitride-based light-emitting diode elements of the present invention The yoke example includes a substrate 丨, an n-type gallium nitride-based semiconductor layer 2 formed on the substrate 2、, and a light-emitting unit 3 formed on the n-type gallium nitride-based semiconductor layer 2 The p-type gallium nitride based semiconductor layer 4 formed on the light-emitting unit 3 and the electrode 5 formed on the n-type gallium nitride-based semiconductor layer 2 and the p-type gallium nitride-based semiconductor layer 4, respectively. The material is a sandwich structure composed of a sapphire substrate 11, a gallium nitride buffer layer 12 and an undoped gallium nitride layer 13, which is a metal organic chemical vapor deposition method (metal_organic chemicai vap〇r deposition; It is called MOCVD). It should be noted that in the following description, each half The epitaxial layers of the conductors are all made by metal organic chemical vapor deposition (71251947), but conventional epitaxial growth methods such as M〇lecuiar Be (MBE) can also be used. The main material of the n-type gallium nitride based semiconductor layer 2 is nitrided and doped with 胄WW, and the n-type semiconductor has a thickness of 3000 nm. 1 light unit 3 has a plurality of a staggered barrier layer 31 and a well layer 32; wherein a lowermost barrier layer 31 is connected to the patterned nitrided semiconducting germanium 2, and the uppermost well layer 32 is associated with the last barrier The layer 33 is connected, and the last barrier layer 33 is connected to the p-type gallium nitride based semiconductor layer 4 opposite to the uppermost well layer 32. The barrier layer 31 described above is made of a material of the chemical formula Un〇.〇3Ga" 7N and has a thickness of 20 nm. The well layer 32 described above is made of a material of the formula In^Ga0.8N, and the well layer 32 has a quantum dot structure with a thickness of 2 nm. The last barrier layer 33 described above is made of a material of the formula InowGaowN and has a thickness of 3 Å. The P-type tantalum nitride-based semiconductor layer 4 is mainly made of gallium nitride (GaN) and doped with 2 x 10 〇 18 cm -3 of magnesium to form a p-type semiconductor having a thickness of 150 nm. Fig. 5 is a view showing the energy level diagram of the light-emitting unit 3 of the preferred embodiment of the present invention with respect to the n-type, germanium-type gallium nitride-based semiconductor. D2 represents the n-type gallium nitride system, and the energy gap 'D31 of the conductor layer 2 indicates that the energy gap of the barrier layer 31 is 2. The energy gap of the well layer 32, D33 represents the energy gap of the last barrier layer 33, and D4 represents the energy gap of the p-type gallium nitride based semiconductor layer 4. It can be seen from the figure that the energy gap D33 of the last barrier layer is smaller than the energy gap 1251947 〇4 of the p-type gallium nitride semiconductor layer*, and is larger than the energy gap Du of the well layer 32, so that the p-type gallium nitride can be increased. The probability of the holes in the semiconductor layer 4 entering the light-emitting unit 3 increases the luminous efficiency. Referring to the comparison diagram of the luminance current curve (Iv-I curve) of FIG. 6, the dotted line indicates the luminance current curve of the conventional gallium nitride-based LED component, and
實線則是指本發明之氮化鎵系發光二極體元件的亮度電流 曲線’可知在相同的工作電流時，本發明之氮化鎵系發光 二極體元件可得到較高亮度。 參閱圖7之電流電壓曲線（i-V curve)比較圖，圖中虛線 指出習知氮化鎵系發光二極體元件的電流電壓曲線，而實 、水貝]疋扎本發明之氮化錄系發光二極體元件的電流電壓曲 線，可知本發明之啟動電壓（threshold voltage)小於習知氮化 鎵系發光二極體元件的啟動電壓，也就是欲達到相同的工 作電流時，本發明之氮化鎵系發光二極體元件所需工作電 壓亦車乂小’故可以有效節省電源，並提高發光效率。 …綜上所述，本發明以化學式為％以(】一的材料製成， 4取後阻障層33,不僅不需要習知的包覆層州，可以^ 化製程，更可以減少晶格成長時的缺陷產生，或是避免： 門口熱u生的應力造成結晶品質降低的問題。另外 -=力:上阻障層32、井層31與最後阻障層33的配合 發明之發光單元3產生比習知更佳的結晶品質 達到本發明之目的。 兀件確貫了 惟以上所述者 僅為本發明之較佳實施例而已，當不 1251947 能以此限定本發明實施之範圍，即大凡依本發明申請專利 範圍及發明說明内容所作之簡單的等效變化與修飾，皆仍 屬本發明專利涵蓋之範圍内。 【圖式簡單說明】 圖1是一習知氮化鎵系發光二極體元件的剖面示意圖 ， 圖2是該習知氮化鎵系發光二極體元件中之局部剖面 示意圖，說明一 η型披覆層、一發光單元和一 p型披覆層 的結構； 圖3是一本發明氮化鎵系發光二極體元件的第一較佳 實施例的剖面示意圖； 圖4是該第一較佳實施例中之局部剖面示意圖，說明 型氮化料、半導體層、—發光單元和―p型氮化嫁系 半導體層的結構； 圖5疋w亥第較佳實施例中，該η型氮化鎵系半導體 層、該發光單元㈣ρ型氮化鎵系半導體層的能階示意圖 圖6疋4第一較佳實施例與習知氮化鎵系發光二極體 元件的亮度電流曲線比較圖；及 一圖7疋°亥第一較佳實施例與習知氮化鎵系發光二極體 元件的電流電壓比較圖。 10 1251947 【主要元件符號說明】 1 «基材 11 ·基板 12 ·緩衝層 13·氮化鎵層 2 ♦ η型氮化鎵系半導體層 3，發光單元 3 1 ♦阻障層 32，井層 33，最後阻障層 4 · ρ型氮化鎵系半導體層 5 ·電極The solid line refers to the luminance current curve ' of the gallium nitride-based light-emitting diode element of the present invention. It can be seen that the gallium nitride-based light-emitting diode element of the present invention can obtain high luminance at the same operating current. Referring to the comparison diagram of the current-voltage curve (iV curve) of FIG. 7, the dotted line indicates the current-voltage curve of the conventional gallium nitride-based light-emitting diode element, and the real and water-shelled light-emitting diodes of the present invention The current-voltage curve of the polar body component shows that the threshold voltage of the present invention is smaller than the starting voltage of the conventional gallium nitride-based light-emitting diode element, that is, the gallium nitride of the present invention when the same operating current is to be achieved. The required operating voltage of the LED component is also small, so it can effectively save power and improve luminous efficiency. In summary, the present invention is made of a material having a chemical formula of % and a barrier layer 33, which not only does not require a conventional coating state, but also can reduce the crystal lattice. Defects during growth occur, or avoid: The problem of lowering the crystal quality caused by the stress of the door opening heat. In addition -= force: the upper barrier layer 32, the well layer 31 and the last barrier layer 33 are combined with the illumination unit 3 of the invention. It is the object of the present invention to produce a better crystalline quality than the prior art. The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the practice of the present invention, i.e., The simple equivalent changes and modifications made by the present invention in accordance with the scope of the invention and the description of the invention are still within the scope of the patent of the present invention. [Fig. 1 is a conventional gallium nitride-based light-emitting diode 2 FIG. 2 is a partial cross-sectional view of the conventional gallium nitride-based light-emitting diode element, illustrating the structure of an n-type cladding layer, a light-emitting unit, and a p-type cladding layer; 3 is a gallium nitride system of the invention FIG. 4 is a partial cross-sectional view showing the first preferred embodiment of the first preferred embodiment, illustrating a nitride material, a semiconductor layer, a light-emitting unit, and a “p-type nitride”. The structure of the semiconductor layer; FIG. 5 is a schematic diagram of the energy level of the n-type gallium nitride-based semiconductor layer and the light-emitting unit (four) p-type gallium nitride-based semiconductor layer. FIG. Comparison of brightness current curves between a preferred embodiment and a conventional gallium nitride based light emitting diode device; and a current and voltage of the first preferred embodiment of the present invention and a conventional gallium nitride based light emitting diode device 10 1251947 [Description of main component symbols] 1 «Substrate 11 · Substrate 12 · Buffer layer 13 · Gallium nitride layer 2 ♦ η-type gallium nitride-based semiconductor layer 3, light-emitting unit 3 1 ♦ barrier layer 32, Well layer 33, last barrier layer 4 · p-type gallium nitride based semiconductor layer 5 · electrode
1111