Engineering of the Interface between Silicon and Rare-Earth-Oxide Buffer for GaN Growth

Abstract

Epitaxial multilayer heterostructures based on rare earth oxides serve as stress mitigating buffers for the growth of GaN on a Si (111) substrate. The process for the formation a uniform amorphous silicon dioxide layer between a silicon substrate and single crystal rare-earth oxide is described. The amorphous silicon dioxide interlayer is formed between the gadolinium oxide and the silicon substrate for additional relief of thermal expansion and lattice mismatch induced stress because of its reduced viscosity at temperatures typical for rare earth oxides and gallium nitride growth.

Study of thermal stability of distributed Bragg reflectors based on epitaxial rare-earth oxide and silicon heterostructures

“…Their density on the surface correlates with thickness of erbium oxide, as is studied in detail elsewhere. 10 The surface defects result in increased roughness of the second Si layer on top of the oxide as indicated by features visible between the specular diffraction maxima and the first order diffraction maxima [ Fig. 1(c)].…”

“…It is expected that the lattice mismatch induced stress will relax in form of mismatch dislocations after reaching critical oxide layer thickness. 10 This could influence performance of the erbium oxide based DBR. Recently, some results of MOCVD growth of GaN on Gd 2 O 3 and Er 2 O 3 double layer were published, proving compatibility of the rare-earth oxides as a buffer.…”