A low stress state composite substrate for gan growth

Abstract

The invention discloses a low stress state composite substrate for GaN growth. The substrate comprises a thermally and electrically conductive substrate, a thermally and electrically conductive bonding dielectric layer of high melting point, a GaN monocrystal epitaxial layer and a stress compensation layer, wherein the melting point of the thermally and electrically conductive substrate is higher than 1000 DEG C, the thermally and electrically conductive bonding dielectric layer is placed on the substrate, and the stress compensation layer is prepared at the back side of the thermally and electrically conductive substrate. A GaN epitaxial wafer is bonded to the thermally and electrically conductive substrate by the high-temperature diffusion bonding technology. 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 a low-stress state and high-temperature stable composite substrate for GaN growth. 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 bulk single crystal is very difficult, large-scale single crystal GaN is difficult to obtain directly, and the price is expensive, the epitaxial growth of GaN material system is mainly based on the lar...

AI Technical Summary

Problems solved by technology

Existing patents (patent application number: 201210068033.0 and patent application number: 201210068026.0) describe the preparation of composite substrates for GaN growth based on low-temperature bonding and laser lift-off technology and its preparation methods, but currently use dielectric bonding The following problems exist in the preparation of thermally and electrically conductive GaN composite substrates with laser lift-off technology: (1) In the past, lower temperature bonding was mainly used below 600 °C, and the high temperature stability was poor, and GaN was already formed when epitaxially growing GaN at a high temperature above 1000 °C. The bonding structure of the substrate will change again, seriously affecting 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 recombination The substrate is warped to a certain extent, and 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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