Ge incorporation inside 4H-SiC during Homoepitaxial growth by chemical vapor deposition

TL;DR

This study investigates the incorporation of germanium during the homoepitaxial growth of 4H-SiC using chemical vapor deposition, revealing how growth parameters influence Ge levels and doping without significantly affecting surface quality.

Contribution

It demonstrates the effects of GeH4 addition on Ge incorporation and doping levels during 4H-SiC growth, highlighting the roles of temperature and gas flux.

Findings

Ge incorporation levels range from 10^17 to 10^18 at.cm^-3.

GeH4 increases n-type doping by 2 to 5 times.

Surface morphology remains largely unaffected by Ge addition.

Abstract

In this work, we report on the addition of GeH4 gas during homoepitaxial growth of 4H-SiC by chemical vapour deposition. Ge introduction does not affect dramatically the surface morphology and defect density though it is accompanied with Ge droplets accumulation at the surface. The Ge incorporation level inside the 4H-SiC matrix, ranging from few 1017 to few 1018 at.cm-3, was found to be mainly affected by the growth temperature and GeH4 flux. Other growth parameters like C/Si ratio, polarity, or off-orientation did not show any significant influence. On the other hand, adding GeH4 led to the increase of the intentional n type doping level by a factor of 2 to 5 depending on the C/Si ratio in the gas phase.