201017928 九、發明說明： 【發明所屬之技術領域】 ' 本發明涉及一種半導體光電元件。 ^【先前技術】 發光二極體（LED，Light Emitting Diode)以其亮度高、 工作電壓低、功耗小、易與積體電路匹配、驅動簡單、壽 命長等優點，從而可作為光源而廣泛應用於照明領域，具 體可參見 Joseph Bielecki 等人於文獻 2007 IEEE，23rd IEEE © SEMI-THERM Symposium 中之 Thermal Considerations for LED Components in an Automotive Lamp —文。發光二極體 係一種可將電流轉換成特定波長範圍之光之半導體元件。 光檢測器係一種可將特定波長範圍之光轉換為電流之半導 體元件。氮化鎵系半導體可用作藍光發光二極體之發光元 件，亦可用作光檢測器之光吸收元件。 氮化鎵系半導體用作藍光發光二極體之發光元件之工 作原理係藉由於氮化鎵系半導體層提供順向偏壓，使電子 ®與空穴於氮化鎵系半導體層中結合，電子與空穴結合釋放 能量而發出特定波長之光，該特定波長之光之波長範圍取 決於氮化鎵系半導體層之導電帶與價電子帶之間之能隙， 一般氮化鎵系半導體層可產生波長介於200nm至1.5 μ m波 長範圍内的光。 氮化鎵系半導體層用作光檢測器之光吸收元件之工作 原理係藉由光入射至氮化鎵系半導體層，並使氮化鎵系半 導體層於逆向偏壓下吸收光能量並產生電子與空穴對，進 201017928 而產生電流’一般氮化鎵系半導體層可用於檢測波長範圍 内介於200nm至i.5/zm波長範圍内的光。 由於先前之形成光檢測器或發光二極體之氮化鎵系半 .導體層之結構有細微之差異，因此，使得先前之氮化鎵系 半導體層使用受到局限。 【發明内容】 有馨於此’有必要提供一種具有可發光且可進行光檢 測之半導體光電元件。 〇 … 種半導體光電元件，其包括：一個基板和一個蟲晶 結構層，該磊晶結構層位於該基板上。該磊晶結構層包括 一個N型半導體層，一個第一 p型半導體層，一個多重量 子井結構層以及一個未摻雜之半導體層。該N型半導體層 所用材料之化學通式為AlaInbGaiabN，其中，ag〇，bg〇, i ga+bg〇。該第一 p型半導體層所用材料之化學通式為201017928 IX. Description of the invention: [Technical field to which the invention pertains] The present invention relates to a semiconductor photovoltaic element. ^ [Prior Art] Light Emitting Diode (LED) is widely used as a light source because of its high brightness, low operating voltage, low power consumption, easy matching with integrated circuits, simple driving, and long life. For use in the field of illumination, see, for example, Joseph Bielecki et al., Literature 2007 IEEE, 23rd IEEE © SEMI-THERM Symposium, Thermal Considerations for LED Components in an Automotive Lamp. A light-emitting diode is a semiconductor component that converts current into light of a specific wavelength range. A photodetector is a semiconductor component that converts light of a particular wavelength range into a current. The gallium nitride-based semiconductor can be used as a light-emitting element of a blue light-emitting diode, and can also be used as a light-absorbing element of a photodetector. The working principle of a gallium nitride-based semiconductor used as a light-emitting element of a blue light-emitting diode is to combine electrons and holes in a gallium nitride-based semiconductor layer by providing a forward bias voltage by a gallium nitride-based semiconductor layer. The combination of the holes and the release of energy to emit light of a specific wavelength, the wavelength range of the light of the specific wavelength depends on the energy gap between the conductive strip and the valence band of the gallium nitride based semiconductor layer, and the gallium nitride based semiconductor layer is generally Produces light with a wavelength in the range of 200 nm to 1.5 μm. The operation principle of the gallium nitride based semiconductor layer as the light absorbing element of the photodetector is that light is incident on the gallium nitride based semiconductor layer, and the gallium nitride based semiconductor layer absorbs light energy under reverse bias and generates electrons. With the hole pair, the current is generated in 201017928. A general gallium nitride based semiconductor layer can be used to detect light in the wavelength range of 200 nm to i.5/zm. Since the structure of the gallium nitride-based semiconductor layer which previously formed the photodetector or the light-emitting diode has a slight difference, the use of the prior gallium nitride-based semiconductor layer is limited. SUMMARY OF THE INVENTION It is necessary to provide a semiconductor optoelectronic component having luminescence and photodetection. A semiconductor optoelectronic component comprising: a substrate and a layer of insect crystal structure, the epitaxial structure layer being on the substrate. The epitaxial structure layer includes an N-type semiconductor layer, a first p-type semiconductor layer, a multi-weight sub-well structure layer, and an undoped semiconductor layer. The material of the N-type semiconductor layer has a chemical formula of AlaInbGaiabN, wherein ag〇, bg〇, i ga+bg〇. The chemical formula of the material used for the first p-type semiconductor layer is
AlcIndGai_c_dN，其中，cg〇, dg〇, 12c+d20。該多重量子 ❹井結構層設置於該N型半導體層與該第一 p型半導體層之 間’該多重量子井結構層所用材料之化學通式為 AlxInyGaix-yN，其中 ’x2〇，y》〇，i2x+y^〇。該未摻雜之 半導體層設置於該N型半導體層與該多重量子井結構層之 間’該未摻雜之半導體層所用材料之化學通式為： AlrInsGai-rsN，其中 ’r2〇，sg〇，lgr+sg〇,且該未摻雜之 半導體層之位壘層能階高於該多重量子井結構層之位壘層 能階（barrier energy levei)。 與先前技術相比，該半導體光電元件包括一個未摻雜 201017928 之半導體層，其於施加順向偏壓下可使得電子與空穴於氮 化鎵系半導體層中結合，電子與空穴結合釋放能量而發出 .特定波長的光，用作發光元件。當施加逆向偏壓時，該未 摻雜之半導體層可降低該半導體光電元件於施加逆向偏壓 <» 下產生之暗電流，以使得該半導體光電元件於光檢測下所 測量得之光電流讀值比光電流與暗電流同時存在時之光電 流讀值更精確，方便光電流感測，以使得該半導體光電元 件於逆向偏壓下可用作光檢測器。該暗電流係指一光檢測 ® 元件於未照光下施以一逆向偏壓時產生之微電流。該光電 流係指一光檢測元件於光照下施以一逆向偏壓，光由該光 檢測元件之光吸收層吸收並形成分離之電子電洞對所產生 之電流。 【實施方式】 請參照圖1，為本發明第一實施例提供之半導體光電元 件100之結構剖面示意圖。該半導體光電元件100包括一 ❹個基板11，一個磊晶結構層12。 該基板11材料可為藍寶石、氮化鎵、銅鎢、矽、碳化 矽或氮化鋁等。 該磊晶結構層12包括一個N型半導體層121，一個第 一 P型半導體層122, 一個設置於該N型半導體層121與 該第一 P型半導體層122之間之多重量子井結構層123,以 及一個未摻雜之半導體層124。 該磊晶結構層 12藉由有機金屬氣相沈積法 (Metal-Organic Chemical Vapor Deposition，MOCVD)沈積 201017928 於該基板11上。 該N型半導體層 121所用材料之化學通式為 AUribGan-bN,其中，a20, b20, 12a+b20。該 N 型半導 體層121中具有摻雜物，用以提供電子。該N型半導體層 121可為N型氮化鎵（n-type GaN )、N型氮化銦鎵（n-type InGaN)、N型氮化鋁鎵（n-type AlGaN)，或係N型氮化鋁 銦鎵（n-typeA10.25In0.25Ga0.5N)等按任意比例組合成之 半導體層。 該第一 P型半導體層122所用材料之化學通式為 AlcIridGaic—dN，其中，c20, d20, lgc+d20。該第一 P 型 半導體層122中具有掺雜物，用以提供空穴。該第一 P型 半導體層122可為P型氮化鎵（p-type GaN)、P型氮化銦 鎵（p-type InGaN )、P型氮化紹鎵（p-type AlGaN )，或是 P型氮化鋁銦鎵（p-type A10.25In0.25Ga0.5N)等按任意比 例組合成之半導體層。 該多重量子井結構層123包括複數交替重疊之半導體 結構層，其所用材料之化學通式為AUnyGai+yN，其中，X 20, y20，12x+y20。具體地，該多重量子井結構層123 包括複數半導體結構層可包括交替重疊之GaN層、InyGal -yN層、GaN層、InyGal -yN層、GaN層等。該多重量子 井結構層123為該半導體光電元件100之主要光活性層 (active layer ) ° 該未摻雜之半導體層124設置於該N型半導體層121 與該多重量子井結構層123之間。該未摻雜之半導體層124 201017928 所用材料之化學通式為：AlJnsGair-sN，其中，rg〇, s^O, 1 2r+s2 0，藉由改變r、s之值即可控制該未掺雜之半導體 „層124之位壘層能階。該未摻雜之半導體層124之位壘層 :能階高於該多重量子井結構層123之位元壘層能階，請一 併參見圖2所示之半導體光電元件100之磊晶結構能階示 意圖。其中，Ec係導電帶能階（conduction band energy level)，Εν 係價電子帶能階（valence band energy level)。該 未摻雜之半導體層124之能階係一位壘層能階，即該未摻 ®雜之半導體層124之能階高於N型半導體層121之能階， 該未掺雜之半導體層124之能階亦高於相鄰之該多重量子 井結構層123之能階，以使得該半導體光電組件100於逆 向偏壓下能有效降低暗電流，以提升光電流之辨別性。 該未摻雜之半導體層124用於降低該半導體光電元件 100於施加逆向偏壓下所產生之暗電流。其中，藉由控制 A1之含量可控制該半導體光電元件100於施加逆向偏壓下 @以作為光檢測器時之光電流與暗電流之比。若A1之含量低 於5%時，將造成該未摻雜之半導體層124之能障過低，無 法有效降低暗電流，若A1之含量高於20%，將造成該未摻 雜之半導體層124之能障過高，進而會降低光電流。因此 該未摻雜之半導體層124中A1之含量優選為：大於或等於 5%，小於或等於20%。同時，該未摻雜之半導體層124厚 度亦將影響該未摻雜之半導體層124之性能。若該未摻雜 之半導體層124之厚度小於lnm時，該未摻雜之半導體層 124容易被電流擊穿而造成穿透現象（tunneling )，使得大 201017928 部分電流從擊穿處通過，造成元件功能降低甚至損壞。若 該未摻雜之半導體層124之厚度大於50nm，則會造成光電 . 流降低，且電阻加大，造成光電流難以量測。因此該未摻 雜之半導體層124厚度一般優選大於或等於lnm且小於或 等於50nm。 該半導體光電元件100進一步包括一個第一電極層 125、一個第二電極層126以及一個緩衝層127。 該第一電極層125設置於該第一 P型半導體層122上， ®該第二電極層126設置於該N型半導體層121之暴露於外 之凸台上，以使得該第二電極層126與該未摻雜之半導體 層124相互分離。組成該第一電極層125與該第二電極層 126之材料可為鈦（Ti)、鋁（A1)、鎳（Ni)、鉑（Pt)、鉻（Cr)、 銅（Au)等金屬或上述任意兩種或多種金屬的合金，或為透 明導電氧化物，如氧化銦錫（In203:Sn，ITO)，氧化銦 辞（ZnO:In，IZO)等。該第一電極層125與該第二電極層126 @ 用於提供該半導體光電元件100之外部電性連接。因此， 於施加順向偏壓下，電子與空穴結合釋放能量而發出特定 波長之光，以使該半導體光電元件100用作發光元件，如 發光二極體。於施加逆向偏壓下，該半導體光電元件100 於光檢測下所測量得之光電流讀值比光電流與暗電流同時 存於時之光電流讀值更精確，方便光電流感測，以使得該 半導體光電元件於逆向偏壓下可用作光檢測器。 該緩衝層127位於該基板11與該N型半導體層121之 間，其材料一般為氮化鎵緩衝層（GaN buffer layer)，該緩 11 201017928 衝層127可藉由有機金屬氣相沈積法而形成於該基板11 上。 ^ 請參照圖3,為本發明第二實施例提供之半導體光電元 件200之結構剖面示意圖。其與第一實施例提供之半導體 光電元件100結構基本相同’不同之處在於.該半導體光 電元件200進一步包括一個第二P型半導體層228。 該第二P型半導體層228位於該第一 P型半導體層222 與該多重量子井結構層223之間。該第二P型半導體層228 ®所用材料之化學通式為：AlwGai_wN，其中，l>wg〇。該 第二P型半導體層228亦可稱作為電流阻擋層（electron blocking layer)或局限層（confinement layer)。於對該半導體 光電元件200施加順向偏壓下，該第二P型半導體層228 用於阻擋電流，減小電子藉由多重量子井結構層223逸出， 以使得電子與空穴於該多重量子井結構層223中相結合， 釋放能量並發光，從而增加該半導體光電元件200於順向 π偏壓下之發光效率，其能階示意圖可一併參見圖4所示。AlcIndGai_c_dN, where cg〇, dg〇, 12c+d20. The multiple quantum well structure layer is disposed between the N-type semiconductor layer and the first p-type semiconductor layer. The chemical formula of the material used in the multiple quantum well structure layer is AlxInyGaix-yN, where 'x2〇, y》〇 , i2x+y^〇. The undoped semiconductor layer is disposed between the N-type semiconductor layer and the multiple quantum well structure layer. The chemical formula of the material used for the undoped semiconductor layer is: AlrInsGai-rsN, where 'r2〇, sg〇 And lgr+sg〇, and the barrier layer energy level of the undoped semiconductor layer is higher than the barrier energy levei of the multiple quantum well structure layer. Compared with the prior art, the semiconductor optoelectronic device comprises a semiconductor layer undoped 201017928, which can combine electrons and holes in the gallium nitride-based semiconductor layer under the application of forward bias, and electrons and holes are combined to release. Light emitted by a specific wavelength is used as a light-emitting element. When a reverse bias is applied, the undoped semiconductor layer can reduce the dark current generated by the semiconductor optoelectronic component under the application of the reverse bias voltage to cause the photocurrent of the semiconductor optoelectronic component to be measured under photodetection. The reading value is more accurate than the photocurrent reading when the photocurrent and the dark current are simultaneously present, which facilitates the photoelectric influenza measurement, so that the semiconductor photovoltaic element can be used as a photodetector under reverse bias. The dark current refers to the microcurrent generated by a photodetection ® component when a reverse bias is applied under unlit light. The photocurrent means that a photodetecting element is subjected to a reverse bias under illumination, the light being absorbed by the light absorbing layer of the photodetecting element and forming a current generated by the separated pair of electron holes. Embodiments Please refer to FIG. 1 , which is a cross-sectional view showing the structure of a semiconductor photo-electric element 100 according to a first embodiment of the present invention. The semiconductor optoelectronic component 100 includes a substrate 11 and an epitaxial structure layer 12. The material of the substrate 11 may be sapphire, gallium nitride, copper tungsten, tantalum, tantalum carbide or aluminum nitride. The epitaxial structure layer 12 includes an N-type semiconductor layer 121, a first P-type semiconductor layer 122, and a multiple quantum well structure layer 123 disposed between the N-type semiconductor layer 121 and the first P-type semiconductor layer 122. And an undoped semiconductor layer 124. The epitaxial structure layer 12 is deposited on the substrate 11 by Metal-Organic Chemical Vapor Deposition (MOCVD). The material of the N-type semiconductor layer 121 has a chemical formula of AUribGan-bN, wherein a20, b20, 12a+b20. The N-type semiconductor layer 121 has dopants therein for supplying electrons. The N-type semiconductor layer 121 may be N-type GaN, N-type InGaN, N-type AlGaN, or N-type. A semiconductor layer in which aluminum indium gallium nitride (n-type A10.25In0.25Ga0.5N) or the like is combined in an arbitrary ratio. The material of the first P-type semiconductor layer 122 has a chemical formula of AlcIridGaic-dN, wherein c20, d20, lgc+d20. The first P-type semiconductor layer 122 has a dopant therein for providing holes. The first P-type semiconductor layer 122 may be P-type GaN, P-type InGaN, or P-type AlGaN, or A P-type aluminum indium gallium nitride (p-type A10.25In0.25Ga0.5N) or the like is combined into a semiconductor layer in an arbitrary ratio. The multiple quantum well structure layer 123 includes a plurality of alternating semiconductor structure layers having a chemical formula of AUnyGai+yN, wherein X 20, y20, 12x+y20. Specifically, the multiple quantum well structure layer 123 includes a plurality of semiconductor structure layers, which may include alternately overlapping GaN layers, InyGal-yN layers, GaN layers, InyGal-yN layers, GaN layers, and the like. The multiple quantum well structure layer 123 is the main active layer of the semiconductor photovoltaic device 100. The undoped semiconductor layer 124 is disposed between the N-type semiconductor layer 121 and the multiple quantum well structure layer 123. The chemical formula of the material used for the undoped semiconductor layer 124 201017928 is: AlJnsGair-sN, wherein rg〇, s^O, 1 2r+s2 0 can be controlled by changing the values of r and s. The impurity layer of the semiconductor layer „layer 124. The barrier layer of the undoped semiconductor layer 124: the energy level is higher than the level of the meta-layer layer of the multiple quantum well structure layer 123, please refer to the figure. 2 is a schematic diagram of the epitaxial structure of the semiconductor optoelectronic device 100, wherein the Ec is a conduction band energy level, and the Εν is a valence band energy level. The energy level of the semiconductor layer 124 is a bit barrier level, that is, the energy level of the undoped semiconductor layer 124 is higher than the energy level of the N-type semiconductor layer 121, and the energy level of the undoped semiconductor layer 124 is also The energy level of the adjacent multiple quantum well structure layer 123 is higher than that of the adjacent multiple quantum well structure layer 123, so that the semiconductor photovoltaic device 100 can effectively reduce the dark current under the reverse bias to improve the discrimination of the photocurrent. The undoped semiconductor layer 124 Used to reduce the generation of the semiconductor photovoltaic device 100 under reverse bias a dark current, wherein the ratio of the photocurrent to the dark current when the semiconductor photo-electric device 100 is used as a photodetector under the reverse bias is controlled by controlling the content of A1. If the content of A1 is less than 5%, The energy barrier of the undoped semiconductor layer 124 is too low to effectively reduce the dark current. If the content of A1 is higher than 20%, the energy barrier of the undoped semiconductor layer 124 is too high, and thus the voltage is lowered. Photocurrent. Therefore, the content of A1 in the undoped semiconductor layer 124 is preferably: 5% or more, less than or equal to 20%. Meanwhile, the thickness of the undoped semiconductor layer 124 will also affect the undoped. The performance of the semiconductor layer 124. If the thickness of the undoped semiconductor layer 124 is less than 1 nm, the undoped semiconductor layer 124 is easily broken down by current to cause tunneling, so that a large portion of the current is hit by the 201017928 Passing through, causing the function of the element to be reduced or even damaged. If the thickness of the undoped semiconductor layer 124 is greater than 50 nm, the photoelectric flow is reduced, and the resistance is increased, so that the photocurrent is difficult to measure. Therefore, the undoped Half The thickness of the bulk layer 124 is generally preferably greater than or equal to 1 nm and less than or equal to 50 nm. The semiconductor photovoltaic device 100 further includes a first electrode layer 125, a second electrode layer 126, and a buffer layer 127. The first electrode layer 125 is disposed on the On the first P-type semiconductor layer 122, the second electrode layer 126 is disposed on the exposed exposed land of the N-type semiconductor layer 121 such that the second electrode layer 126 and the undoped semiconductor layer 124 Separated from each other. The material constituting the first electrode layer 125 and the second electrode layer 126 may be metal such as titanium (Ti), aluminum (A1), nickel (Ni), platinum (Pt), chromium (Cr), copper (Au) or An alloy of any two or more of the above metals, or a transparent conductive oxide such as indium tin oxide (In203:Sn, ITO), indium oxide (ZnO: In, IZO) or the like. The first electrode layer 125 and the second electrode layer 126 @ are used to provide external electrical connection of the semiconductor optoelectronic component 100. Therefore, under the application of the forward bias, electrons combine with the holes to release energy to emit light of a specific wavelength, so that the semiconductor photovoltaic element 100 functions as a light-emitting element such as a light-emitting diode. Under the application of the reverse bias, the photocurrent reading measured by the semiconductor optoelectronic component 100 under the photodetection is more accurate than the photocurrent reading when the photocurrent and the dark current are simultaneously present, so that the photoelectric influenza measurement is facilitated, so that the The semiconductor optoelectronic component can be used as a photodetector under reverse bias. The buffer layer 127 is located between the substrate 11 and the N-type semiconductor layer 121. The material of the buffer layer 127 is generally a GaN buffer layer. The buffer layer 127 can be formed by an organometallic vapor deposition method. It is formed on the substrate 11. Please refer to FIG. 3, which is a cross-sectional view showing the structure of a semiconductor photovoltaic device 200 according to a second embodiment of the present invention. It is substantially identical in structure to the semiconductor optoelectronic component 100 provided by the first embodiment. The difference is that the semiconductor optoelectronic component 200 further includes a second P-type semiconductor layer 228. The second P-type semiconductor layer 228 is located between the first P-type semiconductor layer 222 and the multiple quantum well structure layer 223. The chemical formula of the material used for the second P-type semiconductor layer 228® is: AlwGai_wN, where l>wg〇. The second P-type semiconductor layer 228 can also be referred to as an electron blocking layer or a confinement layer. The second P-type semiconductor layer 228 is used to block current when the forward bias is applied to the semiconductor optoelectronic device 200, and the electrons are reduced by the multiple quantum well structure layer 223, so that electrons and holes are multiplied. The quantum well structure layer 223 combines to release energy and emit light, thereby increasing the luminous efficiency of the semiconductor photovoltaic device 200 under a forward π bias. The energy level diagram can be seen in FIG. 4 together.
G 該半導體光電元件200包括之未摻雜之半導體層224 用於提升該半導體光電元件200作為光檢測元件之電流識 別性，該第二Ρ型半導體層228能有效提高該半導體光電 元件200作為發光元件之發光效率。該半導體光電元件200 可藉由順向偏壓與逆向偏壓下相互轉換。因此，該半導體 光電元件200具備作為發光二極體及光檢測元件之雙重功 能。 請參照圖5，為本發明第三實施例提供之半導體光電元 12 201017928 件300之結構剖面示意圖。該半導體光電元件300包括一 個N型半導體層321，一個第一 P型半導體層322，一個設 ,置於該N型半導體層321與該第一 P型半導體層322之間 之多重量子井結構層323，一個位於該N型半導體層321 與該多重量子井結構層323之間之未摻雜之半導體層 324,以及一個位於該多重量子井結構層323與該第一 P型 半導體層322之間之第二P型半導體層328，一個反射層 329以及一個導電基板33。 ® 該反射層329與該第一 P型半導體層322相連接，其 用於反射光。該反射層329可為鉑、銀或鋁等高反射率金 屬層。該反射層329可藉由電鍍或蒸鍍等方法形成於該第 一 P型半導體層322上。當該半導體光電元件300施加順 向偏壓時，該多重量子井結構層323發出之光可藉由該反 射層329反射回該多重量子井結構層323之遠離該反射層 329之一侧，以增加該半導體光電元件300之發光效率。當 _該半導體光電元件300施加逆向偏壓時，穿過該多重量子 井結構層323且未被其吸收之光藉由該反射層329反射回 該多重量子井結構層323，以增加其光吸收率。因此，該反 射層329可有效增加該半導體光電元件300之發光效率及 光檢測效率。 該導電基板33設置於該反射層329之遠離該第一 P型 半導體層322之一侧，其構成材料可為銅、銅鎢、矽、碳 化石夕或紹等。該基板33藉由共晶接合法（eutectic process) 與該反射層329相連接。該基板33具有良好導熱性與導電 13 201017928 性。因此’電流可藉由該基板33,且該多重量子井結構層 • 323產生之熱量亦可藉由該基板33傳送出去。同時，該基 -板33可增強該半導體光電元件300之機械強度，以防止該 .半導體光電元件300被壓損、變形等。 於本實施例中’第一電極層325設置於該N型半導體 層321上，該第二電極層326設置於基板33上。 綜上所述’本發明確已符合發明專利之要件，遂依法 ❻提出專利申請。惟，以上所述者僅為本發明之較佳實施方 式’自不能以此限制本案之申請專利範圍。舉凡熟悉本案 技藝之人士援依本發明之精神所作之等效修飾或變化，皆 應涵蓋於以下申請專利範圍内。 【圖式簡單說明】 圖1係本發明第一實施例提供之半導體光電元件之結 構剖面示意圖。 圖2係圖1中提供之半導體光電元件之能階示意圖。 Φ 圖3係本發明第二實施例提供之半導體光電元件之結 構剖面示意圖。 圖4係圖3中提供之半導體光電元件之能階示意圖。 圖5係本發明第三實施例提供之半導體光電元件之結 構剖面示意圖。 【主要元件符號說明】 100、200、300 11、33 12 半導體光電元件 基板 遙晶結構層 201017928 N型半導體層 121 、 321 第一 P型半導體層 122 ' 222、322 - 多重量子井結構層 123 ' 223 、 323 未摻雜之半導體層 124 ' 224、324 第一電極層 125 ' 325 第二電極層 126 ' 326 緩衝層 127 第二P型半導體層 228 > 328 ® 反射層 329 〇 15G The semiconductor photo-electric component 200 includes an undoped semiconductor layer 224 for enhancing current identification of the semiconductor optoelectronic component 200 as a photodetecting element, and the second germanium-type semiconductor layer 228 can effectively enhance the semiconductor optoelectronic component 200 as a light-emitting device. The luminous efficiency of the component. The semiconductor optoelectronic component 200 can be converted to each other by a forward bias and a reverse bias. Therefore, the semiconductor photosensor 200 has a dual function as a light emitting diode and a photodetecting element. Please refer to FIG. 5, which is a cross-sectional view showing the structure of a semiconductor photocell 12 201017928 according to a third embodiment of the present invention. The semiconductor optoelectronic device 300 includes an N-type semiconductor layer 321, a first P-type semiconductor layer 322, and a multiple quantum well structure layer disposed between the N-type semiconductor layer 321 and the first P-type semiconductor layer 322. 323, an undoped semiconductor layer 324 between the N-type semiconductor layer 321 and the multiple quantum well structure layer 323, and a layer between the multiple quantum well structure layer 323 and the first P-type semiconductor layer 322 The second P-type semiconductor layer 328, a reflective layer 329 and a conductive substrate 33. The reflective layer 329 is connected to the first P-type semiconductor layer 322 for reflecting light. The reflective layer 329 can be a high reflectivity metal layer such as platinum, silver or aluminum. The reflective layer 329 can be formed on the first P-type semiconductor layer 322 by plating or vapor deposition. When the semiconductor optoelectronic component 300 applies a forward bias, the light emitted by the multiple quantum well structure layer 323 can be reflected back to the side of the multiple quantum well structure layer 323 away from the reflective layer 329 by the reflective layer 329. The luminous efficiency of the semiconductor photovoltaic element 300 is increased. When the semiconductor photovoltaic element 300 is applied with a reverse bias, light that passes through the multiple quantum well structure layer 323 and is not absorbed by it is reflected back to the multiple quantum well structure layer 323 by the reflective layer 329 to increase its light absorption. rate. Therefore, the reflective layer 329 can effectively increase the luminous efficiency and light detection efficiency of the semiconductor photovoltaic device 300. The conductive substrate 33 is disposed on one side of the reflective layer 329 away from the first P-type semiconductor layer 322, and may be made of copper, copper tungsten, tantalum, carbon carbide or the like. The substrate 33 is connected to the reflective layer 329 by a eutectic process. The substrate 33 has good thermal conductivity and electrical conductivity 13 201017928. Therefore, the current can be transmitted through the substrate 33, and the heat generated by the multiple quantum well structure layer 323 can also be transmitted through the substrate 33. At the same time, the base-plate 33 can enhance the mechanical strength of the semiconductor photovoltaic element 300 to prevent the semiconductor photovoltaic element 300 from being crushed, deformed, and the like. In the present embodiment, the first electrode layer 325 is disposed on the N-type semiconductor layer 321, and the second electrode layer 326 is disposed on the substrate 33. In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, which is not intended to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the present invention are intended to be included within the scope of the following claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing the structure of a semiconductor photovoltaic element according to a first embodiment of the present invention. 2 is a schematic diagram of the energy level of the semiconductor optoelectronic component provided in FIG. Φ Fig. 3 is a schematic cross-sectional view showing the structure of a semiconductor photovoltaic element according to a second embodiment of the present invention. 4 is a schematic diagram of the energy level of the semiconductor optoelectronic component provided in FIG. Fig. 5 is a cross-sectional view showing the structure of a semiconductor photovoltaic element according to a third embodiment of the present invention. [Description of main component symbols] 100, 200, 300 11, 33 12 semiconductor photovoltaic device substrate remote crystal structure layer 201017928 N-type semiconductor layer 121, 321 first P-type semiconductor layer 122 '222, 322 - multiple quantum well structure layer 123 ' 223, 323 undoped semiconductor layer 124' 224, 324 first electrode layer 125' 325 second electrode layer 126' 326 buffer layer 127 second p-type semiconductor layer 228 > 328 ® reflective layer 329 〇 15