Encapsulation Studies and Planar Device Fabrication in Gallium Arsenide

摘要

Low temperature photoluminescence and Auger electron spectroscopy (AES) are used to study SIO2 and Si3N4 as encapsulants for high temperature annealing of GaAs. These encapsulants are used in the fabrication of planar diodes in GaAs, and the resulting electrical and optical properties of the devices are examined. Silicon dioxide or silicon oxy-nitride layers allow the outdiffusion of Ga when they are used to encapsulate GaAs during high temperature annealing. .In contrast, silicon nitride layers which are essentially free of oxygen can be used to anneal GaAs with negligible Ga outdiffusion. A versatile rf plasma deposition system capable of depositing high quality Si3N4 films at low temperatures is described. In this system, reacting gases are introduced into the reaction chamber separately, and great care is taken to reduce residual oxygen in the system. Composition (ration of silicon to nitrogen), index of refraction, etch rate, and deposition rate are reported for films deposited under various conditions. Electrical characterization of the Si3N4 films is also presented.