Suppression of threading defects formation during Sb-assisted metamorphic buffer growth in InAs/InGaAs/InP structure

TL;DR

This paper demonstrates a method to suppress threading defect formation in InAs epitaxial layers by using Sb-assisted metamorphic buffers during MOCVD growth, resulting in high-quality virtual substrates.

Contribution

It introduces Sb-assisted InGaAs buffers with a convex compositional gradient to control defect formation during InAs growth, improving epitaxial quality.

Findings

Defect formation is significantly reduced with Sb surfactant use.

Uniform high-quality growth achieved on offcut wafers towards [111]B.

The method enables reliable high-quality InAs epitaxy.

Abstract

A virtual substrate for high quality InAs epitaxial layer has been attained via metalorganic vapor-phase epitaxy growth of Sb-assisted InxGa1-xAs metamorphic buffers, following a convex compositional continuous gradient of the In content from x = 53 % to 100 %. The use of trimethylantimony (or its decomposition products) as a surfactant has been found to crucially enable the control over the defect formation during the relaxation process. Moreover, an investigation of the wafer offcut-dependence of the defect formation and surface morphology has enabled the achievement of a reliably uniform growth on crystals with offcut towards the [111]B direction.