Possible metallicity in SiO and GeO solids

First principles calculations are performed to determine possible structure s and electronic properties of silicon monoxide and germanium monoxide soli ds. For both compounds, an orthorhombically distorted SnO(s) structure is f ound to display the highest stability. The bondings in SiO(s) and GeO(s) di splay considerable degrees of both covalency and ionicity in conjunction wi th significant metallic character in the be planes. SiO(s) is predicted to be a better conductor than GeO(s). Possible importance to CMOS technology i s emphasized as supposedly insulating thin SiO,(s) layers may display local phase separation, resulting in metallic perforation due to microscopic SiO (s) 'spikes'. (C) 2000 Elsevier Science B.V. All rights reserved.