Separation of III–N/SiC epitaxial heterostructure from a Si substrate and their transfer to other substrate types

Abstract

A chemical-etching based method for separating GaN/AlN and AlN epitaxial heterostructures grown on silicon with a silicon-carbide buffer layer and transferring them to substrates of any type is developed. GaN/AlN/SiC and AlN/SiC heterostructures 2.5 μm and 18 μm thick, respectively, are separated and transferred to a glass substrate. It is shown that a silicon-carbide buffer layer on silicon, grown by the substitution method, has a developed subsurface structure which allows easy separation of the film from the substrate and promotes the relaxation of elastic energy caused by a difference in thermal-expansion coefficients of the film and substrate. It is shown that mechanical stresses in the film after its separation from the silicon substrate almost completely relaxed.