Improved Adhesion of P-doped SiO2-Interface Layers on InP by Low-Temperature Damage-Free Plasma-CVD

Abstract

ABSTRACTThe deposition of thin films on III-V compound semiconductors is encountered with various interfacial problems. We present a new approach using a modified plasma technique in a phosphorous ambient at substrate temperatures ranging from 250 to 350 °C which covers two import aspects: Firstly, a good insulator quality due to the plasma process. Secondly, an appropriate surface pre-treatment and defect passivation by a phosphine-like cleaning process using a solid phosphorous source. The analysis of the film adhesion yields improved adhesive properties due to the high activation energy of a plasma process for surface reactions, and by preventing a phosphorus-related defects. The phosphorous concentration in the SiO2 films has to be adapted in order to prevent electrical degradation of the SiO2-InP interface. The influence of phosphorous deficiency and excess phosphorous will be discussed.