Preparation method of low stress state composite substrate for GaN growth

Abstract

The invention discloses a preparation method of a low stress state composite substrate for GaN growth. The preparation method comprises that a GaN monocrystal epitaxial layer is prepared on a sapphire substrate; a stress compensation layer is deposited at the back side of a thermally and electrically conductive transfer substrate of high welding point; bonding dielectric layers of high welding point are prepared at the surfaces of a GaN epitaxial wafer and the transfer substrate respectively; the GaN epitaxial wafer is bonded to the thermally and electrically conductive substrate by the high-temperature diffusion bonding technology; and the composite substrate with high temperature stability and low stress state for GaN growth is obtained. According to the composite substrate of the invention, homoepitaxy can be realized and a vertical structural device can be directly prepared as a traditional composite substrate, the low stress state and high-temperature stability can be also realized, and the quality of subsequent GaN epitaxial growth and chip preparation can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor optoelectronic devices, in particular to transferring a GaN epitaxial film to a thermally conductive substrate by using a high-temperature diffusion bonding process, and combining a stress compensation layer to realize a low-stress thermally conductive composite substrate for GaN homoepitaxial growth method of preparation. Background technique [0002] Wide bandgap GaN-based semiconductor materials have excellent optoelectronic properties and have been widely used in the production of light-emitting diodes, lasers, ultraviolet detectors and high-temperature, high-frequency, high-power electronic devices, and can be applied to the preparation of high-end microelectronics required by aerospace Devices, such as high-mobility transistors (HEMTs) and heterojunction transistors (HFETs), have become research hotspots in the international optoelectronics field. [0003] Since the preparation of GaN...

AI Technical Summary

Problems solved by technology

The patent (patent application number: 201210068033.0 and patent application number: 201210068026.0) describes the preparation of a composite substrate for GaN growth based on low-temperature bonding and laser lift-off technology and its preparation method, but previously used dielectric bonding and laser The following problems exist in the preparation of thermally and electrically conductive GaN composite substrates by the lift-off process: (1) In the past, lower temperatures below 600°C were mainly used for bonding, and the high temperature stability was poor. The combined structure will change again, which will seriously affect the quality of homoepitaxial and chip preparation in the later stage; (2) The changes in the substrate transfer process and thermal and conductive substrates will generate greater stress in the transferred substrate, resulting in composite substrates Some warping occurs, even wrinkles are formed on the GaN epitaxial film, making it difficult to achieve high-performance GaN single crystal epitaxy and chip preparation

Poor high temperature stability and severe stress residue are the main reasons restricting the further application of substrate transfer technology on high-performance GaN composite substrates

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