The Mechanism as SI GaAs Substrate Influences the Resistivity of the Epitaxial Layer

✍ Scribed by K. Somogyi

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 387 KB
• Volume: 27
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/crat.2170270811

✦ Synopsis

Abstract

It is known that it is possible to grow a semi‐insulating or, at least, a high resistivity GaAs epitaxial layer without doping on an SI GaAs substrate by VPE. The SI substrate is suspected as the originator of the high resistivity intermediate layer and diffusion and/or out‐diffusion are accepted as mechanisms explaining this effect. In this work carrier concentration depth profiles were studied in various GaAs multi‐layered epitaxial structures grown on SI GaAs substrates before and after various heat treatment procedures in order to study the diffusion and outdiffusion processes. It is concluded that the role of the diffusion is negligible and the out‐diffusion process is insignificant, and the main, i.e. the determining effect in the compensation process is the growth mechanism of the layer. The impurities set free from the substrate by chemical etching processes rebuilt into the growing layer. In addition formation of EL2 centres may be initiated by As rich gas phase composition following the in‐situ etching.