A Study on the Silane Doping of Hetero-Epitaxial MOCVD Grown GaN

摘要

This paper presents a comprehensive study of SiH_4 doping of GaN grown by metal-organic chemical vapour deposition (MOCVD) on sapphire substrates. The silicon incorporation appeared to be virtually independent of the growth temperature and a 1:1 relationship between the carrier concentration and the input mol fraction silane was found. Optical microscopy was used to study the morphology of the layers where photoluminescence provided a measure of the optical quality. The electrical properties were determined with Hall measurements and a comparison was made with ellipsometry measurements. The relationship between the free carrier concentration and the ellipsometric data made it possible to use ellipsometry as an alternative, quick, contactless and non-destructive technique to determine the free electron concentration in GaN layers doped with silicon.