A method for fabricating a triple-junction solar cell

Abstract

The present application discloses a method for making a triple-junction solar cell, comprising: at a first temperature, introducing a carrier gas and a first reaction source gas into a deposition device, forming an emission region of a bottom cell in the upper surface of a Ge substrate, and forming a nucleation layer of the bottom cell, a first tunneling junction layer, a back field layer of a middle cell, a base region of the middle cell, and an emission region of the middle cell on the upper surface of the Ge substrate, to form a first semiconductor structure, wherein the first reaction source gas includes at least a MO source formed by using an In-113 isotope; stopping the introduction of the first reaction source gas, and annealing the first semiconductor structure; after the annealing is completed, introducing a second reaction source gas and a carrier gas into the deposition device, and sequentially forming a window layer, a second tunneling junction layer, and a top cell of the middle cell on the side of the emission region of the middle cell away from the Ge substrate, wherein the second reaction source gas includes at least a MO source formed by using an In-113 isotope. The present application can improve the radiation resistance of triple-junction solar cells.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a method for manufacturing a triple-junction solar cell. Background Art

[0002] The GaInP / GaInAs / Ge triple junction solar cell is a multi-junction solar cell composed of a GaInP top cell, a GaInAs middle cell, a Ge bottom cell and two tunnel junctions. Compared with traditional Si and GaAs single junction solar cells, it has the advantages of stable structure, high reliability, long life, small size and light weight, high photoelectric conversion efficiency, and high light absorption coefficient. It has become the core component of the space power system and is widely used in the power system of spacecraft. However, when the existing GaInP / GaInAs / Ge triple junction solar cell is used as a space power source, its radiation resistance needs to be improved. Summary of the invention

[0003] In view of the above problems, the present application provides a method for manufacturing a triple-junction solar cell to achieve the purpose of improving the radiation resistance of the triple-junction solar cell. The specific scheme is as follows:

[0004] The present application provides a method for manufacturing a triple-junction solar cell, comprising:

[0005] Placing the Ge substrate into a deposition device;

[0006] At a first temperature, a carrier gas and a first reaction source gas are introduced into the deposition device to form an emission region of a bottom battery in the upper surface of the Ge substrate, and a nucleation layer of the bottom battery, a first tunneling junction layer, a back field layer of the middle battery, a base region of the middle battery and an emission region of the middle battery are formed on the upper surface of the Ge substrate to form a first semiconductor structure, wherein the first reaction source gas includes at least a MO source formed by using In-113 isotopes;

[0007] Stopping the introduction of the first reaction source gas into the deposition device, and continuing to introduce the carrier gas, to anneal the first semiconductor structure;

[0008] After annealing is completed, a second reaction source gas and a carrier gas are introduced into the deposition equipment to sequentially form a window layer, a second tunnel junction layer and a top cell of the middle cell on the side of the emission region of the middle cell away from the Ge substrate, wherein the second reaction source gas includes at least a MO source formed using the In-113 isotope.

[0009] In a possible implementation, the first reaction source gas includes a MO source formed using Ga-71 and In-113 isotopes.

[0010] In a possible implementation, the second reaction source gas includes a MO source formed using Ga-71 and In-113 isotopes.

[0011] In a possible implementation, the carrier gas includes argon or nitrogen.

[0012] In a possible implementation, the concentration of argon in the carrier gas is greater than 7N.

[0013] In a possible implementation manner, annealing the first semiconductor structure includes:

[0014] The temperature in the deposition device is lowered from a first temperature to a second temperature and maintained for a preset time to reduce the H content in the middle battery.

[0015] In a possible implementation, the second temperature ranges from 550° C. to 600° C., and the preset time ranges from 200 seconds to 600 seconds.

[0016] In a possible implementation, the method further includes:

[0017] An ohmic contact layer is formed on a side of the top cell away from the Ge substrate.

[0018] By means of the above technical scheme, the manufacturing method of the triple-junction solar cell provided by the present application, while adopting an MO source with a low neutron capture cross-section, also adds an annealing step after the emission region of the middle cell is formed and before the window layer of the middle cell is formed, thereby reducing the content of impure hydrogen in the GaInAs sub-cell and increasing the carrier mobility of the GaInAs sub-cell, further reducing the impact of high-energy particle irradiation on the GaInP / GaInAs / Ge triple-junction solar cell, and improving the radiation resistance of the GaInP / GaInAs / Ge triple-junction solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.

[0020] Figure 1 A flow chart of a method for manufacturing a triple-junction solar cell provided in this application;

[0021] Figure 2 A schematic structural diagram of a triple-junction solar cell manufactured by a method for manufacturing a triple-junction solar cell provided in this application. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the embodiments in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0023] It is obvious to those skilled in the art that various modifications and changes can be made in this application without departing from the spirit or scope of this application. Therefore, this application is intended to cover modifications and changes of this application that fall within the scope of the corresponding claims (technical solutions claimed for protection) and their equivalents. It should be noted that the implementation methods provided in the embodiments of this application can be combined with each other without contradiction.

[0024] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0025] As described in the background technology section, when the existing GaInP / GaInAs / Ge triple-junction solar cells are used as space power sources, their radiation resistance needs to be improved.

[0026] This is because when the existing GaInP / GaInAs / Ge triple junction solar cells are used as space power sources, they are affected by high-energy particle radiation, causing the semiconductor materials of each sub-cell to undergo irradiation displacement damage, resulting in a decrease in the carrier diffusion length, which affects the collection of photogenerated carriers in the solar cell and further affects the current density of the GaInP / GaInAs / Ge triple junction solar cell. Sharps PR et al. mentioned that when the irradiation energy is 1MeV and the injection is 1E15cm -2 When the temperature is increased by 200 °C, the quantum efficiency of the GaInP top cell decreases by 3%, and the quantum efficiency of the GaInAs sub-cell decreases by 22%, resulting in the deterioration of the performance of the triple-junction solar cell.

[0027] Specifically, when the existing GaInP / GaInAs / Ge triple-junction solar cells are used as space power sources for long-term operation in orbit, they will be affected by radiation damage from high-energy particles in space. Radiation damage from high-energy particles such as protons, neutrons and electrons in the space environment will cause the performance parameters of the solar cells to degrade, and in severe cases may even cause the spacecraft power supply system to fail.

[0028] Taking neutrons as an example, neutron irradiation can cause displacement damage effects in solar cells. This is mainly because neutrons collide through elastic scattering, causing the target atomic nuclei in the semiconductor material of the sub-cell to obtain enough energy to leave their lattice positions, resulting in displacement damage defects in the semiconductor material, causing the short-circuit current density of the solar cell to decrease, leading to degradation of solar cell performance or even failure.

[0029] It should be noted that the relationship between the minority carrier lifetime and the incident neutron flux in semiconductor materials is as follows:

[0030] (1);

[0031] in, is the minority carrier lifetime before neutron irradiation; is the minority carrier lifetime after neutron irradiation; is the incident neutron fluence; is the minority carrier lifetime damage factor.

[0032] From formula (1), it can be seen that neutron irradiation will cause the minority carrier lifetime in semiconductor materials to decrease, thereby reducing the current density of triple-junction solar cells. In addition, neutron irradiation will also cause changes in other electrical parameters (such as effective doping concentration, carrier mobility, etc.) in semiconductor materials in addition to the minority carrier lifetime, resulting in a decrease in the electron collection efficiency of solar cells.

[0033] The applicant's research found that the radiation resistance of triple-junction solar cells can be improved by improving the solar cell process, but the improved process is quite different from the existing process and the verification cycle is long; alternatively, the radiation resistance of triple-junction solar cells can be improved by adjusting the structure of the solar cells, but this method will cause the cell performance to change, increase the epitaxial growth time of the solar cells, increase the cost of the solar cells, and lead to uncontrollable factors such as warping of the solar cell epitaxial wafers.

[0034] In view of this, the present application provides a method for manufacturing a triple-junction solar cell, such as Figure 1 As shown, the production method includes:

[0035] S1: Place the Ge substrate into a deposition device. Specifically, in one embodiment of the present application, the Ge substrate has an electrical conductivity of 2x10 18 cm -3 ~8x10 18 cm -3 The P-type Ge substrate may be used, but this application does not limit this and it depends on the specific circumstances.

[0036] Optionally, in one embodiment of the present application, the deposition equipment is a MOCVD (Metal-organic Chemical Vapor Deposition) equipment, but the present application does not limit this and it depends on the specific circumstances.

[0037] S2: At a first temperature, a carrier gas and a first reaction source gas are introduced into the deposition equipment to form an emission region of a bottom battery on the upper surface of the Ge substrate, and a nucleation layer of a bottom battery, a first tunneling junction layer, a back field layer of a middle battery, a base region of a middle battery and an emission region of a middle battery are formed on the upper surface of the Ge substrate to form a first semiconductor structure, wherein the first reaction source gas includes at least a MO source formed using In-113 isotopes.

[0038] Specifically, in one embodiment of the present application, at a first temperature, a carrier gas and a first reaction source gas are introduced into the deposition device to form an emission region of a bottom battery in the upper surface of the Ge substrate, and a nucleation layer of the bottom battery, a first tunneling junction layer, a back field layer of the middle battery, a base region of the middle battery, and an emission region of the middle battery are formed on the upper surface of the Ge substrate to form a first semiconductor structure, including:

[0039] The pressure in the reaction chamber of the deposition device is adjusted to a preset value, and the growth temperature is adjusted to a first temperature. Optionally, the preset value is 50 mbar, and the first temperature is 620° C., but this application does not limit this, and it depends on the specific situation;

[0040] Introducing a carrier gas and a first reaction source gas into the deposition device, wherein the first reaction source gas includes at least an MO source formed using an In-113 isotope;

[0041] The emission region of the Ge subcell, i.e. the emission region of the bottom cell, is formed by the diffusion of PH3 in the Ge substrate;

[0042] By adopting MOCVD process, a nucleation layer of the bottom battery, a first tunneling junction layer, a back field layer of the middle battery, a base region of the middle battery and an emitter region of the middle battery are sequentially formed on the side of the emitter region of the bottom battery away from the Ge substrate to manufacture a first semiconductor structure.

[0043] Specifically, in one embodiment of the present application, the nucleation layer of the bottom battery is an N-type GaInP nucleation layer; the first tunnel junction layer includes a stacked Si-doped GaAs layer and a C-doped GaAs layer, the back field layer of the middle battery is a P-type AlGaAs layer, the base region of the middle battery is a Zn-doped P-type GaInAs layer, and the emitter region of the middle battery is an N-type GaInAs layer.

[0044] Optionally, in the above embodiment, the first reaction source gas also includes reaction source gases such as trimethylindium (TMIn), trimethylgallium (TMGa), trimethylaluminum (TMAl), diethylzinc (DEZn), silane (SiH4) and arsine (AsH3), and the present application does not impose any limitation on this, as long as it can provide the various components required for the first semiconductor structure.

[0045] It should be noted that the radiation sensitivity parameters of GaInP / GaInAs / Ge triple-junction solar cells induced by different energy particles have different degrees of attenuation damage. The use of semiconductor materials with low capture cross-sections can greatly reduce radiation damage. For example, when using boron atoms with an atomic mass number of 11 as acceptor impurities and antimony Sb with an atomic mass number of 123 as donor impurities, when irradiated with radiation, the nuclear reaction experienced by the impurity is much smaller than that of other isotopes, so the impurity concentration changes very little, the electrical properties will not change, and the device has good radiation resistance.

[0046] The applicant has found that different isotopes of In have different neutron capture cross sections, and the neutron capture cross section of In-113 isotope is smaller than that of In-115 isotope, as shown in Table 1 below:

[0047] Table 1

[0048]

[0049] It can be seen from Table 1 that the neutron capture cross section of the In-113 isotope is much smaller than the neutron capture cross section of the In-115 isotope. Therefore, in the embodiment of the present application, the first reaction source gas includes at least MO source TMGa and TMIn formed by the In-113 isotope. When the nucleation layer GaInP layer of the bottom cell and the base region and the emission region of the middle cell (GaInAs sub-cell) are grown, when the high-energy particle injection amount is equivalent, the influence of high-energy particles on the nucleation layer of the bottom cell and the middle cell in the triple-junction solar cell is reduced, and the number of displacement defects in the nucleation layer of the bottom cell and the middle cell in the triple-junction solar cell is reduced, thereby reducing the influence of high-energy particle irradiation on the GaInP / GaInAs / Ge triple-junction solar cell and improving the radiation resistance of the triple-junction solar cell.

[0050] Optionally, based on the above embodiments, in one embodiment of the present application, the first reaction source gas includes MO sources TMGa and TMIn formed by Ga-71 and In-113 isotopes.

[0051] It should be noted that the neutron capture cross sections of different Ga isotopes are also different. The neutron capture interface of Ga-71 isotope is smaller than that of Ga-69 isotope, and the neutron capture cross section of In-113 isotope is smaller than that of In-115 isotope, as shown in Table 2 below:

[0052] Table 2

[0053]

[0054] Therefore, in the embodiment of the present application, the first reaction source gas uses an MO source formed by isotopes of Ga and In (i.e., Ga-71 and In-113) with low neutron capture cross-sections to grow the GaInP layer of the bottom cell and the base region and the emission region of the GaInAs sub-cell (i.e., the middle cell). When the amount of high-energy particle injection is equivalent, the impact of high-energy particles on the GaInP layer and GaInAs sub-cell of the bottom cell can be further reduced, and the number of displacement defects in the GaInP layer and GaInAs sub-cell of the bottom cell can be reduced, thereby reducing the impact of high-energy particle irradiation on the GaInP / GaInAs / Ge triple-junction solar cell and improving the radiation resistance of the triple-junction solar cell.

[0055] S3: Stop introducing the first reaction source gas into the deposition device, keep introducing the carrier gas, and anneal the first semiconductor structure.

[0056] It should be noted that in the MOCVD epitaxial growth of semiconductor materials, if the first reaction source gas includes the group V source gas AsH3, the group V source gas AsH3 will form a large number of free H ions during the cracking process, which will form Zn-H bonds and Mg-H bonds with the doping sources Zn and Mg, etc., so that the H impurity content in the epitaxial material increases, resulting in a decrease in the carrier mobility of the material, thereby affecting the carrier mobility in the first semiconductor structure.

[0057] In addition, if the H impurity in the epitaxial material is too high, it is easy to passivate the doping of the material, reduce the number of hole carriers in the first semiconductor structure, reduce the open circuit voltage and short circuit current density of the triple junction solar cell, and affect the radiation resistance of the triple junction solar cell.

[0058] In the manufacturing method provided in the embodiment of the present application, after the first semiconductor structure is manufactured, the first reaction source gas is stopped from being introduced into the deposition device, while the carrier gas is kept introduced to anneal the first semiconductor structure. This can reduce the H impurity content in the first semiconductor structure and increase the carrier mobility of the first semiconductor structure, thereby increasing the carrier mobility of the triple-junction solar cell and improving the radiation resistance of the triple-junction solar cell.

[0059] Optionally, in one embodiment of the present application, annealing the first semiconductor structure includes: reducing the temperature in the deposition device from the first temperature to the second temperature, and maintaining it for a preset time to reduce the H content in the battery. Specifically, in one embodiment of the present application, the second temperature has a value range of 500°C to 600°C, and further, the second temperature has a value range of 550°C to 600°C; the preset time has a value range of 200 seconds to 600 seconds, and further, the preset time has a value range of 200 seconds to 500 seconds. The present application does not limit this, and it depends on the specific situation.

[0060] It should be noted that, during the annealing process of the first semiconductor structure, the higher the first temperature, the shorter the preset time, and the lower the first temperature, the longer the preset time, so as to ensure the effect of reducing the H impurity content in the first semiconductor structure and improve the carrier mobility of the first semiconductor structure.

[0061] S4: After annealing is completed, a second reaction source gas and a carrier gas are introduced into the deposition equipment to sequentially form a window layer, a second tunnel junction layer and a top cell of the middle cell on the side of the emission region of the middle cell away from the Ge substrate, wherein the second reaction source gas includes at least MO source TMGa and TMIn formed by In-113 isotopes.

[0062] Optionally, in one embodiment of the present application, after annealing is completed, a second reaction source gas and a carrier gas are introduced into the deposition equipment, and an MOCVD process is used to sequentially form a window layer, a second tunnel junction layer and a top battery of the middle battery on the side of the emission region of the middle battery away from the Ge substrate. This is not limited in the present application and depends on the specific circumstances.

[0063] Specifically, in one embodiment of the present application, the top cell includes a top cell back surface field layer 010 , a top cell base region 011 , a top cell emitter region 012 , and a top cell window layer 013 .

[0064] Optionally, in one embodiment of the present application, the window layer of the middle cell is an N-type AlInP window layer, the second tunnel junction layer includes a stacked Si-doped GaInP layer and a C-doped AlGaAs layer, the back field layer of the top cell is a P-type AlGaInP layer, the base region of the top cell is a Zn-doped P-type GaInP layer, the emitter region of the top cell is an N-type GaInP layer, and the window layer of the top cell is an N-type AlInP layer.

[0065] In this embodiment, the second reaction source gas includes at least an MO source formed by using In-113 isotopes, which can reduce the impact of high-energy particles on the top cell in the triple-junction solar cell when growing the top cell and reduce the number of displacement defects in the top cell in the triple-junction solar cell, thereby reducing the impact of high-energy particle irradiation on the GaInP / GaInAs / Ge triple-junction solar cell and improving the radiation resistance of the triple-junction solar cell.

[0066] Optionally, based on the above embodiments, in one embodiment of the present application, the second reaction source gas includes MO source TMGa and TMIn formed by Ga-71 and In-113 isotopes to grow the top cell. When the amount of high-energy particle injection is equivalent, the impact of high-energy particles on the top cell can be further reduced, and the number of displacement defects in the top cell can be reduced, thereby reducing the impact of high-energy particle irradiation on the GaInP / GaInAs / Ge triple-junction solar cell and improving the radiation resistance of the triple-junction solar cell.

[0067] Based on the above embodiments, in one embodiment of the present application, the second reaction source gas also includes: PH3, SiH4, TMAl and TMIn and other reaction source gases. The present application does not limit this, as long as it can provide the window layer of the middle battery and the various components required for the formation of the top battery.

[0068] It should be noted that the V group source gas PH3 does not form a similar Zn-H bond. Therefore, in the embodiment of the present application, after the top cell is grown and before other processes are performed, no annealing step is required. It is only necessary to turn off the first reaction source gas including AsH3 for annealing after the middle cell GaInAs emission region is grown and before the AlInP window layer of the middle cell is grown, thereby reducing the content of impure hydrogen in the GaInAs sub-cell (middle cell), thereby improving the carrier mobility of the GaInAs sub-cell and further reducing the impact of high-energy particle irradiation on the GaInP / GaInAs / Ge triple-junction solar cell.

[0069] It can be seen that in the triple-junction solar cell provided in the embodiment of the present application, the first reaction source gas and the second reaction source gas both use at least an MO source formed by the In-113 isotope, so that when growing the bottom cell, the middle cell and the top cell of the triple-junction solar cell, under the condition of a similar high-energy particle injection amount, the influence of high-energy particles on the epitaxial wafers including the bottom cell, the middle cell and the top cell in the triple-junction solar cell is reduced, and the number of displacement defects in the epitaxial wafers in the triple-junction solar cell is reduced, thereby reducing the influence of high-energy particle irradiation on the GaInP / GaInAs / Ge triple-junction solar cell and improving the radiation resistance of the triple-junction solar cell.

[0070] On the basis of any of the above embodiments, in one embodiment of the present application, the carrier gas includes argon or nitrogen to further reduce the H impurity content in the first semiconductor structure and improve the carrier mobility of the first semiconductor structure.

[0071] Optionally, in one embodiment of the present application, the carrier gas is high-purity argon (Ar gas) or nitrogen (N2 gas). Specifically, in one embodiment of the present application, the argon (Ar gas) or nitrogen (N2 gas) in the carrier gas is greater than 7N, but the present application does not limit this, and it depends on the specific situation. It should be noted that in materials science, the "N" representation of purity is a common expression method used to describe the purity of the material; wherein the number after "N" represents the number of 9s after the decimal point in the material. For example, a material with N purity has a purity of 99.99999%. In this embodiment, the argon (Ar gas) or nitrogen (N2 gas) in the carrier gas is greater than 7N, indicating that the content of argon (Ar gas) or nitrogen (N2 gas) in the carrier gas is greater than 99.99999%.

[0072] Based on any of the above embodiments, in one embodiment of the present application, the method for manufacturing a triple-junction solar cell further includes: forming an ohmic contact layer and other structures on the side of the top cell away from the Ge substrate. Optionally, the ohmic contact layer is an N-type GaAs layer, but the present application does not limit this, and it depends on the specific situation.

[0073] From the above, it can be seen that the method for manufacturing a triple-junction solar cell provided in the embodiment of the present application, while adopting an MO source with a low neutron capture cross-section, also cooperates with specific carrier gas and annealing conditions to reduce the content of impure hydrogen in the GaInAs sub-cell, improve the carrier mobility of the GaInAs sub-cell, and further reduce the impact of high-energy particle irradiation on the GaInP / GaInAs / Ge triple-junction solar cell.

[0074] The following describes the method for manufacturing the triple-junction solar cell provided in the embodiments of the present application in conjunction with specific embodiments.

[0075] Embodiment 1:

[0076] In this embodiment, the method for manufacturing the triple-junction solar cell includes:

[0077] The conductivity is set to 2x10 18 cm -3 ~8x10 18 cm -3 P-type Ge is used as a growth substrate and placed into the reaction chamber of the deposition equipment of the MOCVD system;

[0078] The pressure of the reaction chamber is set to 50 mbar, the growth temperature is set to 620 ° C, and Ar is used as a carrier gas to introduce a first reaction source gas into the reaction chamber. The first reaction source gas includes: trimethyl indium (TMIn), trimethyl gallium (TMGa), trimethyl aluminum (TMAl), diethyl zinc (DEZn), silane (SiH4) and arsine (AsH3) and other reaction source gases, wherein TMGa and TMIn use MO sources formed by Ga-71 and In-113 isotopes (Ga-69 isotopes in natural Ga are removed, and In-115 isotopes in natural In are removed), and The emission region of the Ge subcell (i.e., the bottom cell) is formed by diffusion of PH3 in the Ge substrate, and then an N-type GaInP nucleation layer (i.e., the nucleation layer of the bottom cell), a first tunneling junction layer (i.e., GaAs:Si / GaAs:C tunneling junction) including stacked Si-doped GaAs layers and C-doped GaAs layers, a P-AlGaAs back field layer (i.e., the back field layer of the middle cell), a Zn-doped P-type GaInAs layer (i.e., the base region of the middle cell), and an N-type GaInAs emission region (i.e., the emission region of the middle cell) are sequentially grown on the side of the emission region of the Ge subcell (i.e., the bottom cell) away from the Ge substrate;

[0079] Then, all III and V source gases such as AsH3, TMGa and TMIn were immediately turned off, and only Ar was retained as the carrier gas. The temperature in the reaction chamber was lowered by 35°C and kept for 300 seconds for annealing;

[0080] Then, source gases such as PH3, SiH4, TMAl and TMIn are turned on simultaneously to introduce a second reaction source gas into the reaction chamber, and an N-type AlInP window layer (i.e., the window layer of the middle cell) is first grown on the side of the emitter region of the middle cell away from the Ge substrate, and then a second tunneling junction layer (i.e., GaInP:Si / AlGaAs:C tunneling junction) including stacked Si-doped GaInP layers and C-doped AlGaAs layers, a P-type AlGaInP back field layer (i.e., the back field layer of the top cell), a Zn-doped P-type GaInP layer (i.e., the base region of the top cell, P-GaInP:Zn base region), an N-type GaInP emitter region (i.e., the emitter region of the top cell), an N-type AlInP window layer (i.e., the window layer of the top cell) and an N-type GaAs ohmic contact layer are sequentially grown to form an epitaxial wafer of a triple-junction solar cell provided in an embodiment of the present application.

[0081] Embodiment 2:

[0082] In this embodiment, the method for manufacturing the triple-junction solar cell includes:

[0083] The conductivity is set to 2x10 18 cm -3 ~8x10 18 cm -3P-type Ge is used as a growth substrate and placed into the reaction chamber of the deposition equipment of the MOCVD system;

[0084] The pressure of the reaction chamber is set to 50 mbar, the growth temperature is set to 620 ° C, and Ar is used as a carrier gas to introduce a first reaction source gas into the reaction chamber. The first reaction source gas includes: trimethyl indium (TMIn), trimethyl gallium (TMGa), trimethyl aluminum (TMAl), diethyl zinc (DEZn), silane (SiH4) and arsine (AsH3) and other reaction source gases, wherein TMGa and TMIn use MO sources formed by Ga-71 and In-113 isotopes (Ga-69 isotopes in natural Ga are removed, and In-115 isotopes in natural In are removed), and The emission region of the Ge subcell (i.e., the bottom cell) is formed by diffusion of PH3 in the Ge substrate, and then an N-type GaInP nucleation layer (i.e., the nucleation layer of the bottom cell), a first tunneling junction layer (i.e., GaAs:Si / GaAs:C tunneling junction) including stacked Si-doped GaAs layers and C-doped GaAs layers, a P-AlGaAs back field layer (i.e., the back field layer of the middle cell), a Zn-doped P-type GaInAs layer (i.e., the base region of the middle cell), and an N-type GaInAs emission region (i.e., the emission region of the middle cell) are sequentially grown on the side of the emission region of the Ge subcell (i.e., the bottom cell) away from the Ge substrate;

[0085] Then, all III-group and V-group source gases such as AsH3, TMGa and TMIn were immediately turned off, and only Ar was retained as the carrier gas. The temperature in the reaction chamber was lowered by 55°C and kept for 560 seconds for annealing.

[0086] Then, the reaction source gases such as PH3, SiH4, TMAl and TMIn are turned on at the same time to introduce the second reaction source gas into the reaction chamber, and an N-type AlInP window layer (i.e., the window layer of the middle cell) is first grown on the side of the emission region of the middle cell away from the Ge substrate, and then a second tunneling junction layer (i.e., GaInP:Si / AlGaAs:C tunneling junction) including a stacked Si-doped GaInP layer and a C-doped AlGaAs layer, a P-AlGaInP back field layer (i.e., the back field layer of the top cell), a Zn-doped P-type GaInP layer (i.e., the base region of the top cell, P-GaInP:Zn base region), an N-GaInP emission region (i.e., the emission region of the top cell), an N-type AlInP window layer (i.e., the window layer of the top cell) and an N-type GaAs ohmic contact layer are sequentially grown to form the epitaxial wafer of the triple-junction solar cell provided in the embodiment of the present application.

[0087] like Figure 2As shown, the triple-junction solar cell manufactured by the method for manufacturing a triple-junction solar cell provided in the embodiment of the present application includes: a Ge substrate 001, a first sub-cell (bottom cell) emitter region 002, a nucleation layer 003, a first tunneling junction layer 004, a second sub-cell (i.e., middle cell) back field layer 005, a second sub-cell (i.e., middle cell) base region 006, a second sub-cell (i.e., middle cell) emitter region 007, a second sub-cell (i.e., middle cell) window layer 008, a second tunneling junction layer 009, a third sub-cell (i.e., top cell) back field layer 010, a third sub-cell (i.e., top cell) base region 011, a third sub-cell (i.e., top cell) emitter region 012, a third sub-cell (i.e., top cell) window layer 013 and an ohmic contact layer 014 and other structures located sequentially on one side of the Ge substrate 001.

[0088] It can be seen that the manufacturing method of the triple-junction solar cell provided in the embodiment of the present application can improve the radiation resistance of the GaInP / GaInAs / Ge triple-junction solar cell without changing the epitaxial structure of the triple-junction solar cell, by improving the MO source material of the epitaxial growth and cooperating with the improvement of the epitaxial growth method. It is compatible with the existing process and will not change the electrical properties of the triple-junction solar cell, nor will it increase the epitaxial growth time of the solar cell, thereby not increasing the cost of the solar cell, and will not cause uncontrollable factors such as warping of the solar cell epitaxial wafer.

[0089] In summary, the method for manufacturing a triple-junction solar cell provided in the embodiment of the present application adopts an MO source formed by isotopes of Ga and In with low neutron capture cross sections to grow GaInP and GaInAs sub-cells, and when the amount of high-energy particle injection is equivalent, the impact of high-energy particles on the epitaxial layer is reduced, and the number of displacement defects in the epitaxial layer is reduced, thereby reducing the impact of high-energy particle irradiation on the GaInP / GaInAs / Ge triple-junction solar cell. At the same time, while adopting an MO source with a low neutron capture cross section, the present application also cooperates with specific carrier gas and annealing conditions to reduce the content of impurity hydrogen in the GaInAs sub-cell, increase the carrier mobility of the GaInAs sub-cell, further reduce the impact of high-energy particle irradiation on the GaInP / GaInAs / Ge triple-junction solar cell, and do not change the electrical properties of the triple-junction solar cell, with good radiation resistance, low cost, and high yield.

[0090] In this specification, each embodiment is described in a progressive, parallel, or progressive and parallel manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0091] It should be noted that in the description of the present application, it should be understood that the description of the drawings and embodiments is illustrative rather than restrictive. The same reference numerals throughout the embodiments of the specification identify the same structure. In addition, for the sake of understanding and ease of description, the drawings may exaggerate the thickness of some layers, films, panels, regions, etc. It is also understood that when an element such as a layer, film, region, or substrate is referred to as "on" another element, the element may be directly on the other element or there may be an intermediate element. In addition, "on" refers to positioning an element on or below another element, but does not essentially refer to positioning on the upper side of another element according to the direction of gravity.

[0092] The terms "upper", "lower", "top", "bottom", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. When a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally arranged component at the same time.

[0093] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the article or device including the above elements.

[0094] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for manufacturing a triple-junction solar cell, characterized in that: include: Placing the Ge substrate into a deposition device; At a first temperature, a carrier gas and a first reaction source gas are introduced into the deposition device to form an emission region of a bottom battery in the upper surface of the Ge substrate, and a nucleation layer of the bottom battery, a first tunneling junction layer, a back field layer of a middle battery, a base region of the middle battery and an emission region of the middle battery are formed on the upper surface of the Ge substrate to form a first semiconductor structure, wherein the first reaction source gas includes at least a MO source formed by using In-113 isotopes, and the nucleation layer is located on a side of the emission region away from the Ge substrate; Stopping the introduction of the first reaction source gas into the deposition device, and continuing to introduce the carrier gas, to anneal the first semiconductor structure; After the annealing is completed, a second reaction source gas and a carrier gas are introduced into the deposition device to sequentially form a window layer, a second tunneling junction layer and a top cell of the middle cell on the side of the emission region of the middle cell away from the Ge substrate, wherein the second reaction source gas includes at least a MO source formed by using In-113 isotopes; Wherein, annealing the first semiconductor structure includes: reducing the temperature in the deposition equipment from a first temperature to a second temperature, and maintaining it for a preset time to reduce the H content in the battery, the second temperature ranges from 550°C to 600°C, and the preset time ranges from 200 seconds to 600 seconds.

2. The method for manufacturing a triple-junction solar cell according to claim 1, characterized in that: The first reaction source gas includes a MO source formed by using Ga-71 and In-113 isotopes.

3. The method for manufacturing a triple-junction solar cell according to claim 1, characterized in that: The second reaction source gas includes a MO source formed by using Ga-71 and In-113 isotopes.

4. The method for manufacturing a triple-junction solar cell according to claim 1, characterized in that: The carrier gas includes argon or nitrogen.

5. The method for manufacturing a triple-junction solar cell according to claim 4, characterized in that: The concentration of argon in the carrier gas is greater than 7N.

6. The method for manufacturing a triple-junction solar cell according to claim 1, characterized in that: Also includes: An ohmic contact layer is formed on a side of the top cell away from the Ge substrate.

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