Preparation method of a diamond-based gallium nitride composite substrate

Abstract

The invention provides a method for preparing a diamond-based gallium nitride (GaN) composite substrate, which belongs to the field of semiconductor material preparation. Firstly, the diamond film was friction-polished to make the surface roughness less than 0.5 nm. Then, based on the vacuum interconnected radio frequency magnetron sputtering and molecular beam epitaxy technology, the double-chamber thin film plating is carried out. When the vacuum reaches 1×10 ‑5 Pass into Ar and N after Pa 2 And keep the working vacuum at 0.3-0.5 Pa, the diamond substrate temperature at 400-600 °C, and the radio frequency power at 400-500 W to deposit a highly oriented c-AlN thin layer of 10 nm-200 nm. Then move the substrate to the molecular beam epitaxy chamber, deposit a 20nm-50nm GaAlN transition layer, and increase the temperature to 700-900°C to deposit a GaN single crystal layer with the required thickness. Finally, the obtained substrate is heat-preserved to obtain a high-quality diamond-based GaN composite substrate. The method of the invention is applicable to a diamond-based gallium nitride composite substrate.

Description

technical field [0001] The invention belongs to the field of semiconductor material preparation and relates to a preparation method of a diamond-based gallium nitride composite substrate. Background technique [0002] As the third-generation semiconductor material after Si and GaAs, GaN has the characteristics of large band gap, high breakdown electric field strength, high saturated electron velocity, high thermal conductivity and strong radiation resistance. It has extremely high application value and development prospects in the fields of white light LEDs, short-wavelength lasers, ultraviolet detectors, and high-temperature and high-power devices. Due to the special stability of GaN (melting point 2791 K, melting pressure 4.5 GPa), there is a lack of natural GaN bulk single crystal materials in nature, and the current main work is carried out on heterogeneous epitaxy on SiC, Si, diamond and other substrates. However, due to the lattice mismatch and thermal mismatch betwee...

AI Technical Summary

Problems solved by technology

The mainstream low-temperature bonding technology and the direct deposition of diamond on the back of the GaN epitaxial layer to prepare the diamond substrate GaN wafers have complex processes and the hydrogen plasma environment required for diamond growth can damage GaN.

Research on the bonding technology of diamond substrates and GaN epitaxial layers needs to overcome some current technical bottlenecks: 1) The low-temperature bonding technology needs to be upgraded to reduce the cost of diamond processing and achieve low thermal resistance and high-quality bonding strength standards of the bonding layer; 2) For the GaN epitaxial layer backside deposition technology, through the high-efficiency transfer of the GaN epitaxial layer, the thermal conductivity of the diamond nucleation layer is improved, and the large area of ​​the diamond substrate deposited by the GaN epitaxial layer is the research direction; 3) Other technical means mainly exist The small size of the single crystal diamond substrate, the compatibility of the nano-diamond passivation layer deposition process and device processing, etc., will greatly limit the development and application of these technical means

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