6results about How to "Improve epitaxy quality" patented technology

This invention provides a gallium arsenide triple-junction solar cell and its fabrication method, relating to the field of solar cell technology. It replaces the existing technology's self-forming Ge substrate with a low-cost N-type GaAs substrate and a thinner N-type Ge epitaxial layer. The thickness of the N-type Ge epitaxial layer ranges from 1 μm to 3 μm, reducing material costs by more than 40%. A two-step growth method is used to form a stacked low-temperature nucleation layer and a high-temperature host layer to form the N-type Ge epitaxial layer, which serves as the base cell of the gallium arsenide triple-junction solar cell. The epitaxial quality is high, with a dislocation density of the N-type Ge epitaxial layer less than or equal to 5 × 10⁻⁶. 6 cm ‑2 This effectively suppresses the problem of Ga / Ge interdiffusion; the photoelectric conversion efficiency of this gallium arsenide triple junction solar cell has been verified to be greater than 30%, which is comparable to the photoelectric conversion efficiency of gallium arsenide triple junction solar cells with Ge substrates forming their own bottom cells in existing technologies.

A high luminous efficiency LED epitaxial wafer structure belongs to the technical field of light emitting diodes, and comprises a substrate, and a buffer layer, an unintentional doping layer, an N-GaN layer, a first well layer, a second well layer, a built-in EBL layer, a quantum well light emitting layer, a P-type electron blocking layer and a P-GaN layer which are sequentially deposited on the substrate, the unintentional doping layer is a U-type GaN layer, the built-in EBL layer is an ALGaN layer, and the P-GaN layer is a P-type GaN layer; the temperature of the first well layer and the second well layer is increased in the epitaxial process, H2 is introduced into the first well layer and the H2 introduction amount of the first well layer is greater than that of the second well layer, so that the epitaxial quality of the quantum barrier is improved, and the dislocation defect is reduced; the built-in EBL layer is arranged, the built-in EBL layer is an ALGaN layer, electrons can be effectively blocked by utilizing the characteristic that the forbidden band width of AlGaN is large, and the electron utilization rate can be further improved; the interface processing layer is arranged, bottom layer derivation dislocation is eliminated through pause discontinuous barrier crystal annihilation, the lattice quality is improved, the composite luminous efficiency is improved, and finally the luminous efficiency of the product is greatly improved.

This invention relates to the field of semiconductor technology and discloses a surface planarization method for epitaxial group III nitride materials based on a 3D mask substrate. The method includes using an etchant to achieve anisotropic etching rate differences between the c, a, and m faces of the group III nitride material, thereby performing surface planarization on the epitaxially grown group III nitride material layer. The surface planarization process is a solution etching process. This invention only requires placing the epitaxial group III nitride material on the 3D mask substrate in a mixed solution of potassium hydroxide and sodium chloride or a mixed solution of phosphoric acid and sodium chloride under specific conditions for chemical wet etching. Sodium chloride can increase the etching rate difference between the horizontal and vertical surfaces of the uneven epitaxial GaN layer, while potassium hydroxide or phosphoric acid solutions will etch the protruding parts of the uneven epitaxial group III nitride material layer surface, making the GaN thickness uniform throughout the entire epitaxial wafer, thus achieving global planarization.

The application discloses an epitaxial equipment, which comprises a frame body, a transmission cavity, a gate valve, an adjusting assembly and a reaction cavity are arranged in the frame body, the transmission cavity is installed at one end of a support, the other end of the support away from the transmission cavity is fixed to the bottom of the frame body, and the transmission cavity is connected with the reaction cavity through the gate valve; the adjusting assembly is installed at the top of the frame body, and the adjusting assembly comprises a first connecting part and a guide rail assembly, the guide rail assembly comprises a guide rail and a slider matched with the guide rail, the slider is connected with the first connecting part, and the first connecting part is connected with the reaction cavity. Thus, the distance between the reaction cavity and the transmission cavity can be adjusted through the adjusting assembly, the operation space of the gate valve is sufficient during replacement and maintenance, and the efficiency of the gate valve maintenance and replacement is improved.

The utility model discloses a GaN-based HEMT (High Electron Mobility Transistor) device structure. Comprising a substrate, a nitride buffer layer, a nitride channel layer and a nitride barrier layer, a pattern layer is also arranged between the substrate and the nitride buffer layer; the pattern layer comprises a first structure layer, a second structure layer and a third structure layer, the first structure layer comprises a plurality of convex structures, the second structure layer covers the top surfaces and the side surfaces of the plurality of convex structures, and the third structure layer continuously covers the second structure layer and part of the substrate between the adjacent convex structures; the second structural layer is a film layer with passivation doping, and the third structural layer is a film layer with a nanoporous structure. The lateral epitaxial growth capability of nitride materials is improved, dislocation extension is blocked, and the epitaxial quality is improved; according to the GaN-based HEMT device and the manufacturing method thereof, the two-dimensional electron gas in the nitride channel layer is prevented from being influenced by charge aggregation, so that the stability of drain electrode output current in the nitride channel layer is ensured, current collapse is avoided, and the GaN-based HEMT device with excellent performance is obtained.

The disclosed embodiment provides a method for preparing an aluminum nitride film, comprising: preparing an aluminum nitride film semi-finished product on a substrate; continuing to deposit aluminum nitride on the semi-finished product using a first physical vapor deposition process to obtain an aluminum nitride film finished product; the volume flow ratio of nitrogen and argon in the first physical vapor deposition process is greater than 95:5. Under the condition of an extremely high nitrogen flow percentage, the sputtered aluminum atoms form tiny grains with nitrogen (nitrogen atoms) before being deposited on the surface of the aluminum nitride film, and the tiny grains are deposited on the surface of the aluminum nitride film in a uniform and refined deposition manner, so that the surface of the aluminum nitride film presents a uniform flocculent structure. The aforementioned flocculent structure can better adapt to the growth of the epitaxial layer, facilitate epitaxial recrystallization, reduce epitaxial layer growth dislocations and stresses, and improve epitaxial quality.