Process for growth of low dislocation density GaN
AssigneeSaint-Gobain Cristaux & Detecteurs
InventorsBernard Beaumont, Jean-Pierre Faurie, Pierre Gibart
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Abstract
High quality free standing GaN is obtained using a new modification of the Epitaxial Lateral Overgrowth technology in which 3D islands or features are created only by tuning the growth parameters. Smoothing these islands (2D growth) is achieved thereafter by setting growth conditions producing enhanced lateral growth. The repetition of 3D-2D growth results in multiple bending of the threading dislocations thus producing thick layers or free standing GaN with threading dislocation density below 106 cm−2.
Claims17
A method of manufacturing low defect density GaN involving the following steps:
- a) growth of an epitaxial layer of GaN directly on a surface of a substrate, wherein the substrate is chosen from the group consisting of sapphire, spinel, GaN, AlN, GaAs, Si, SiC (6H-, 4H-, 3C-), LiAlO2, LiGaO2, ZrB2, and HfB2;
- b) subsequent growth of a GaN layer to form island features;
- and
- c) growth of a GaN layer from the island features at conditions where lateral growth is enhanced until full coalescence of the island features without using any kind of mask, wherein step b) is achieved without using any kind of mask, nor roughening, nor etching, nor grooving the GaN surface, and only by changing a combination of the operating pressure in the growth chamber, the partial pressure, the temperature, the V/III ratio and/or surfactant or antisurfactant chemical species in the vapour phase, wherein the temperature during step b) is below 950° C., and wherein growth of the GaN layer is carried out at a rate of at least about 50 microns/hour.
Dependencies are inferred from the claim text.