PLASMA-POLYMERIZED TETRAMETHYL GERMANIUM FILMS DEPOSITED AT ELEVATED SUBSTRATE TEMPERATURES

Thin plasma polymerized films of tetramethyl germanium are deposited a t various substrate temperatures. The influence of substrate temperatu re on the deposition rate, composition, structure, and electrical prop erties of the films is discussed. With an increase in the substrate te mperature from 25-degrees-C to 150-degrees-C under similar plasma depo sition conditions, the conductivity of the film increased by four orde rs of magnitude. Films of plasma polymerized tetramethyl germanium dep osited at 150-degrees-C show typical semiconducting behavior (increasi ng conductivity with increasing temperature) and have a sheet conducti vity of 1.0 X 10(-6) S cm-1 at 25-degrees-C. There is a direct correla tion between the conductivity and the composition of the films, i.e., the higher the conductivity the higher the ratio of germanium to carbo n at the surface. At deposition temperatures of 25 and 75-degrees-C th e germanium to carbon ratio was essentially the same, but at a deposit ion temperature of 150-degrees-C, this ratio was considerably higher.