Structural modifications induced in hydrogenated amorphous Si/Ge multilayers by heat treatments

TL;DR

This paper investigates how heat treatments affect the structural integrity of hydrogenated amorphous Si/Ge multilayers, revealing layer intermixing and surface degradation caused by hydrogen bubble formation during annealing.

Contribution

It provides new insights into the structural modifications and degradation mechanisms of hydrogenated amorphous Si/Ge multilayers under various annealing conditions.

Findings

Annealing causes layer intermixing at higher temperatures.

Surface degradation manifests as bumps and craters.

Hydrogen release from Ge layers contributes to bubble formation.

Abstract

A study is presented of the structural changes occurring as a function of the annealing conditions in hydrogenated amorphous Si/Ge multilayers prepared by sputtering. Annealing changes the structure of the as-deposited multilayer except for the less severe conditions here applied (150 oC, time<22 h). For higher temperatures and/or times, the modifications consist of layer intermixing and surface degradation in the shape of bumps and craters. They are argued to be due to the formation of H bubbles upon heating. Hydrogen should be mostly released from the amorphous Ge layers.