HYDRAZINE CYANURATE AS A NITROGEN-SOURCE FOR THIN NITRIDE FILM GROWTH

The use of liquid hydrazine (N2H4) as a nitrogen source for nitridatio n reactions has been restricted because of safety, purity, and difficu lties in using a liquid source. Hydrazine cyanurate (HC) is a stable s olid complex of N2H4 which can be easily handled and purified before u se and which evolves pure N2H4 upon heating, thus making it a promisin g source of N2H4 for nitridation reactions. In this article, a process for the synthesis of HC has been developed which decreases the H2O co ntent of the evolved N2H4 from 10% when H2O was used as the solvent in the synthesis of HC to 0.7% by replacing H2O with dimethylsulfoxide a s the solvent in the synthesis of HC. The use of the purified HC is de monstrated as a solid source in the nitridation of (100) GaAs substrat es at 200 degrees C in a low pressure chemical vapor deposition reacto r. The nitridated GaAs surfaces were analyzed by x-ray photoelectron s pectroscopy and were found to be primarily comprised of GaN, GaAs, and Ga2O3. The ratio of the constituent peak heights in the Ga 3d peak of GaN to Ga2O3 was 2.25 in the grown nitride films. The oxide impuritie s were most likely due to incomplete removal of the native substrate o xide formed prior to growth and were not a product of the nitridation. (C) 1998 American Vacuum Society.