Semiconductor substrate and preparation method thereof

Abstract

The invention provides a preparation method of a semiconductor substrate, comprising the following steps: providing a lithium aluminate wafer, and depositing an AIN membrane layer on the lithium aluminate wafer by a sputtering method to obtain the semiconductor substrate. In the method, lithium aluminate crystal is taken as a substrate and then the AIN membrane layer is deposited on the substrateby the sputtering method to obtain the semiconductor substrate, wherein, due to small lattice mismatch between lithium aluminate and GaN, when the lithium aluminate crystal is taken as the GaN crystal growth substrate, a GaN epitaxial thin film can be prepared easily and high defect density caused by stress can be reduced. When the AIN membrane layer with the same crystal structure and similar lattice constant with the GaN is deposited on the lithium aluminate wafer, the problem that a GaN epitaxial wafer is easily cracked resulting from thermal expansion difference between the lithium aluminate crystal and the GaN is solved; in addition, AIN is taken as a buffer layer and can prevent volatilization of Li in the lithium aluminate substrate and protect the lithium aluminate substrate from corrosion of acidic or reducing atmosphere.

Description

technical field [0001] The invention relates to the field of semiconductors, in particular to a semiconductor substrate and a preparation method thereof. Background technique [0002] Group III-IV nitrides (InN, GaN, AlN) represented by GaN and their ternary and quaternary alloys have wide band gap, high electron drift saturation velocity, high thermal conductivity, high breakdown field strength, and high temperature resistance. It is an important direct band gap semiconductor material with excellent physical and chemical properties such as acid and alkali corrosion resistance, and has great application potential in blue light-emitting diodes, laser diodes, short-wavelength photodetection devices, and high-frequency high-power electronic devices. [0003] However, it is very difficult to grow GaN single crystals. At present, the growth of GaN thin films is mainly based on c-plane sapphire substrates, or using hydrogenated epitaxy (HVPE) to grow GaN self-supporting substrates...

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to provide a preparation method capable of preparing a semiconductor substrate, through which the lithium aluminate substrate is improved to overcome the corrosion-prone, Li Volatility, and the problem of easy cracking of GaN due to the difference in thermal expansion coefficient between lithium aluminate and GaN

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