TWI380460B - Photovoltaic device with broadband multi-layer anti-reflection composite structure and method of fabricating the same - Google Patents

Description

1380460 VI. Description of the Invention: [Technical Field] The present invention relates to a photovoltaic device and a method of fabricating the same, and in particular, to a broadband multi-layer anti-reflective composite structure layer (broadband multi- Photovoltaic element of layer anti-reflection composite structure and method of manufacturing the same. [Prior Art] A photovoltaic element is converted into electric power by a quantity that is easily taken from a light source (for example, sunlight) to control, for example, a computer, a computer, an add-on device, etc., so that photovoltaics Components have been widely used. ", please refer to the figure -, - the traditional photovoltaic element - Shi Xi solar cell (4) (10) solar cell)! A cross-sectional view of its layered stacked structure is depicted in Figure 1. The solar cell 1 typically contains. 丄.... -1. The death of P-11 "σ (Ρ-η d Ρ_η joint 13 is sandwiched between a type of substrate 12 and an n-type "showing: an illuminated surface (front surface) 11 at this place. = The solar cell i1 structure shown in Figure 1 contains - moderately doped (concentration is about 妒em.3 fσ ^ this ^ and one is located on the substrate 12) And adjacent to the Zhao-/two, the explosive material (8)12 thought 1020 cm, the type area (n+)14. The transmission of ''=== degree is concretely _, and it contains its commercialization and covers the η The size of the type zone 14 is for example 'Oxite Day' (or by thick _5, - covered in the table she 3

6UCHIP/200901TW 1380460 π, an n-type metal contact layer 17 as an electrode, a p+ type region 18 covering a surface of the p-type substrate 12, and a surface covering one surface of the P+ type region 18 P-type metal contact layer 19.

The shallow p-n junction 13 is designed to facilitate the collection of electrons and holes. The 'electrons and holes are generated on both sides of the p_n junction 13. Each photon of the light enters the stone substrate 12 and is absorbed by the stone substrate 12 to transfer the energy of the photon to the electron that is originally in the bonding state (covalent bond), and thereby release the original bonding state. The electrons become free electrons. Such movable electrons, as well as the holes left in the covalent bond (the holes are also movable), contain one of the potential elements of the current flowing from the solar cell. In order to contribute to this current, the above-mentioned electrons and holes cannot be recombined, but instead are separated by the electric field associated with the 7_n junction 13. If the electrons are separated from the hole, the electrons will move to the n-type metal contact layer 17, and the hole will move to the p-type metal contact layer 19. With the development of photovoltaic elements such as solar cells, the structure that produces photoelectric effects has also been studied, for example, the technology of multi-junetiGn, which can absorb the p_n junction of a wider spectrum of light. The various types of photoelectric effect structures in photovoltaic elements are not described here. Obviously, the anti-reflection layer of photovoltaic elements should also be widened. Therefore, the present invention provides a photovoltaic element having a broadband multi-layer anti-reverse composite structure layer and a method of fabricating the same. SUMMARY OF THE INVENTION A photovoltaic element according to a preferred embodiment of the present invention comprises a semiconductor structure combination and a layer anti-reflective composite structure layer conductor structure combination comprising at least a -ρ·η junction, and having a top surface An anti-reverse composite structure layer is formed on the top surface of the semiconductor structure combination.

6UCHIP/200901TW 4 The odd-numbered layer in the multilayer anti-reverse composite structure layer is formed by SiO 2 , A 120 3 or MgF 2 . The even number of layers in the multilayer anti-composite structure layer are formed of Ti3〇5. In particular, the multilayer anti-reflective composite structure layer can operate in a wide range of visible light wavelength ranges from about 400 nm to 700 nm. The manufacturing method of the photovoltaic element according to a preferred embodiment of the present invention is first formed to form a semiconductor structure. combination. The semiconductor structure assembly includes at least one p-n junction and has a top surface. Finally, the fabrication method forms a multilayer anti-reverse composite structure layer on the top surface of the semiconductor structure combination. The odd-numbered layer in the multilayer anti-composite structure layer is formed of Si〇2, Al2〇3 or MgF2. The even number of layers in the multilayer anti-composite structure layer are formed by Ti3〇5. In particular, the multilayer anti-reflective composite layer can operate over a wide range of visible wavelengths from about 400 nm to about 700 nm. In one embodiment, the multilayer anti-reflective composite structural layer is formed by an electron-beam evaporation process. And in particular, the multilayer anti-reflective composite structure layer can be formed directly by the electron beam evaporation process using a hard mask. The advantages and spirit of the present invention will be further understood from the following detailed description of the invention. [Embodiment] The present invention provides a photovoltaic element and a method of manufacturing the same, and in particular, a photovoltaic element according to the present invention has a multilayer anti-reverse composite structure layer of a wide frequency. Preferred embodiments in accordance with the present invention are disclosed below. Referring to Figure 1, Figure 1 is a cross-sectional view of a photovoltaic element 2 in accordance with one of the preferred embodiments of the present invention. The PV Secret 2 contains:: half

6UCHIP/200901TW 5 1380460 Anti-reflective composite structural layer 24. The multilayer anti-reverse composite, .,. The structure 24 has a structure of 疋3, 5, 7, 9, 11 or 11 or more layers. The semiconductor structure combination 22 includes at least a -p_n junction 222^ which is shown as a p-n junction 222. As shown in FIG. 2, the semiconductor structure combination 22 has

The structural layer 24 is repeatedly read over the top surface 224 of the conductor layer _ 0 22 . The multilayer anti-reverse composite structure layer % may be a structure of 2, 5, 7, 9, 11 or more layers. It is emphasized that the multi-layer anti-reflective composite structure layer 24 can operate over a range of wavelengths ranging from about 4 nm to about 700 nm. m In accordance with a method of fabricating a photovoltaic device in accordance with a preferred embodiment of the present invention, first, a semiconductor structure combination is formed. The semiconductor structure has a P-η junction and has a top surface.匕3 to

Finally, the manufacturing method according to the present invention is to form a coating film composed of two compounds on the top surface of the semiconductor structure combination, thereby forming a multilayer anti-reflective composite structural layer on the top surface of the semiconductor structure combination, that is, Photovoltaic element 2 shown in Figure 2. Again, the multilayer anti-reflective composite structure layer can operate over a wide range of visible wavelengths from about 400 nm to about 700 nm. Referring to FIG. 2 again, the odd-numbered layer 242 of the multilayer anti-reverse composite structure layer 24 is formed of Si〇2, Al2〇3 or MgF2. Further, the even-numbered layer 244 of the multilayer anti-reflective structure layer 24 is formed of Ti305. In one embodiment, the top surface 224 of the semiconductor structure assembly 22 is subjected to surface texturing to reduce the reflectivity of the incident light to 1 〇〇/0. In practical applications, in response to various types of photoelectric effect junctions in photovoltaic elements

6 6UCHIP/200901TW 1380460, the material of the top surface 224 of the semiconductor structure combination 22 may be a silicon, GaAs, InGaP, CuInSe, CuInGaSe or CdTe, which is formed on the above material and used as a protective layer. Oxide. s In one embodiment, the multi-layer anti-reflective composite structural layer 24 is formed by an electron beam evaporation process. In order to make the fresh-layer anti-reflective composite structure ^ 24, each of the secret products f is better, the upper ship's steaming process can be used to collect an ion-assisted electron beam evaporation process (i〇n_assisted eleetiOn_beam evaporation process). Like a typical photovoltaic element, a photovoltaic element 2 in accordance with a preferred embodiment of the present invention also requires electrodes to be formed on the top surface 224 of its semiconductor structure combination 22 (not shown in particular in Figure 2, the multilayer anti-reflection The composite junction 24 can be formed by a hard-masked straight-line electron-steaming process. Thereby, the process of forming the multilayer anti-reverse composite layer 24 of the photovoltaic element 2 and the electrode can be simplified. β, β are here. It should be emphasized that the multilayer anti-reflection composite structure layer according to the present invention is characterized in that it can operate between a wide range of visible light ray diagrams from about 400 nm to 700 nm. The multi-layer anti-domain composite junction degree according to the present invention (4) is not limited to multiple layers. In addition to the theory of effective admittance, it is also necessary to consider the refractive index of the material covered by the multilayer anti-reflective composite structure layer, and it is necessary to consider that the refractive index of the coating material itself varies with the wavelength of the incident light. Change. Therefore, in practical operation, it is necessary to first simulate the overall light of a multilayer anti-reverse composite structure layer with different layers and different coating materials on a specific semiconductor material by computer simulation. Please refer to Figure 3, Figure 4 and Figure 5. Figure 3 shows the formation of Si〇2 and Ti on the InGaP substrate. The stacking of 5 layers of anti-reverse composite structure layers is performed on different wavelengths. The reflection spectrum of light is shown in Figure 3 and the thickness of each layer of mineral film is shown. Figure 4 is a simulation of the formation of a12〇3 and Ti305 on the InGaP substrate and stacking them into 5 layers of anti-reverse composite structure layer for different wavelengths of light. Anti-radio

6UCHIP/200901TW 7 1380460 spectrum, shown in Figure 4 and lists the thickness of each layer of the bond film. Figure 5 is a simulation of the reflection spectrum of the formation of MgF2 and Ti3〇5 on an InGaP substrate by stacking five layers of anti-reverse composite structures to different wavelengths of light. Figure 5 shows the thickness of each layer of mineral film. From the results of Fig. 3, Fig. 4 and Fig. 5, it is clearly shown that the five-layer anti-reverse composite structure layer of the above different materials can reduce the reflectance of light having a wavelength ranging from 400 nm to 700 nm to less than 10%. Please refer to Figure 6. Figure 6 shows the reflection spectrum of different wavelengths of light formed by simulating the stacking of si〇2 and Ti3〇5 on the InGaP substrate into 7 layers, 9 layers and 11 layers of anti-reverse composite structure layers. From the results of Fig. 6, it is clearly shown that the multi-layer anti-reverse composite structure layer of the above different layers has a reflectance for light having a wavelength ranging from 4 〇〇 nm to 700 nm, and the reflectance is shown in the figure of 9 layers and layers. Can be reduced to below 0.5%. From a technical point of view, the multilayer antireflective composite structural layer formed of a plurality of compounds formed on various semiconductor materials mentioned in this patent specification can operate over a wide range of visible light wavelengths from about 400 nm to 700 nm. The features and spirits of the present invention are intended to be more apparent from the detailed description of the preferred embodiments. On the contrary, the purpose is to cover the various changes and equals _ arranged in the application of the invention (4) 2 (4), b, the S= description of the patent scope of the application for the ride is the broadest interpretation, so that it covers All changes and equivalent arrangements are available.

6UCHIP/200901TW 8 1380460 [Simplified Schematic] Figure 1 is a cross-sectional view of a conventional tantalum solar cell 1. Figure 2 is a cross-sectional view schematically showing a photovoltaic element 2 in accordance with a preferred embodiment of the present invention. Figure 3 is a simulation of the formation of SiO2 and Ti305 on the InGaP substrate. The five-layer anti-reverse composite structure layer is used to reflect the reflection spectrum of different wavelengths of light. Figure 4 is a simulation of the inverse of the formation of a layer of anti-reverse composite structure layer of A1203 and Ti305 on the InGaP substrate. Figure 5 is a simulation of the formation of a multi-layer anti-reverse composite structure layer of MgF2 and Ti305 on the InGaP substrate. The reflection frequency of the light of different wavelengths is shown in Fig. 6. The simulation is performed on the InGaP substrate to form the 〇2 and 丨3丨5 Interactive stacking

Into 5 spectrum. The reflection spectrum of different layers of the 7-layer, 9-layer and bismuth layer anti-reverse composite structure layers. [Description of main component symbols] 1 : 矽 solar cell 12 : p-type substrate 14 : η-type region 16 : anti-reflection layer 11 : irradiation surface 13 , 222 · gt η bonding 15 : surface passivation layer 17 : n type Metal contact layer

6UCHIP/200901TW 9 1380460 18 : p+ type region 2: photovoltaic element 224: top surface 242: odd-numbered layer 19: p-type metal contact layer 22: semiconductor structure combination 24: multilayer anti-reverse composite structure layer 244: even number Floor

10 6UCHIP/200901TW

Claims (1)

1380460 VII. Patent Application Range 1. A photovoltaic device comprising: a semiconductor structure combination, the semiconductor structure combination comprising at least one pn junction and having a top surface; a multi-layer anti-reflection composite structure layer formed on the top surface of the semiconductor structure combination, the odd-numbered layer of the multilayer anti-reflective composite structure layer Formed by a material selected from the group consisting of SiO 2 , A 120 3 , and MgF 2 •, the multilayer anti-reflective composite structure layer is formed by alternating even-numbered layers formed by Ti305, wherein the multilayer anti-reflection The composite structural layer can operate over a wide range of wavelengths from about 400 nm to about 700 nm. 2. The photovoltaic device of claim 1, wherein the top surface of the semiconductor structure combination is selected from the group consisting of oxides, silicium, GaAs, InGaP, CuInSe, CuInGaSe, and CdTe. One of the groups is provided. 3. A method of fabricating a photovoltaic device, the method comprising the steps of: forming a semiconductor structure combination comprising at least one p_n junction njunction) and having a top surface; Forming a multi-layer anti-reflection composite structure on the top surface, the odd-numbered layer of the multilayer anti-reflective composite structure layer is selected from the group consisting of Si〇2, Al2〇3, and MgF2 Formed by one of the materials in a group, the even number of layers of the multilayer anti-reflective composite structure layer is formed by Ti3〇5 material, wherein the multi-layer 6UCHIP/200901TW 11 1380460 layer anti-reflective composite structure layer can be It operates over a wide range of wavelengths from 4 〇〇 nm to 700 nm. 4. The method of claim 3, wherein the multilayer anti-reflective composite structure is formed by an elec^on seven eam evaporate process. 5. The method of claim 4, wherein the multilayer anti-reflective composite structure is formed by the electron beam plating process using a hard mask. 6. The method of claim 4, wherein the electron beam evaporation process is a plasma assisted electron beam evaporation process (i〇n_assisted eiectr〇n_beam evaporation process). 7. The method of claim 3, wherein the top surface of the semiconductor structure combination is selected from the group consisting of oxides, silic(R), GaAs, InGaP, (TuInSe 'CuInGaSe W & CdTe One of the group consisting of 0 6UCHIP/200901TW 12