Unexpected aspects of strain relaxation and compensation in InGaAs metamorphic structures grown by MOVPE

TL;DR

This paper explores innovative stack designs for MOVPE-grown InGaAs metamorphic buffers, revealing unexpected methods to manage defect generation and strain, enabling the growth of thick tensile strained layers with minimal relaxation.

Contribution

It introduces novel stack configurations that control strain and defects in metamorphic buffers, providing new insights into strain relaxation mechanisms.

Findings

Thick tensile strained layers can be grown without significant relaxation.

Defect generation can be minimized through specific compositional gradients.

Unexpected behaviors in strain management were observed and reported.

Abstract

We present a selection of stack designs for MOVPE grown InxGa1-xAs metamorphic buffer layers following various convex-down compositional continuous gradients of the In content, showing that defect generation and strain can be managed in a variety of ways, some rather unexpected (and unreported). Indeed, we observe that it is possible to grow surprisingly thick tensile strained layers on metamorphic substrates, without significant relaxation and defect generation. We believe our findings give significant insights to the investigation of strain, relaxation and defect distribution in metamorphic buffer design, so to obtain properly engineered/tailored structures (the most successful ones already finding applications in device growth).