DEPOSITION AND PROPERTIES OF GERMANIUM CARBON FILMS DEPOSITED FROM TETRAMETHYLGERMANIUM IN A PARALLEL-PLATE RF DISCHARGE/

Thin germanium/carbon films were prepared by an RF glow discharge deco mposition of tetramethylgermanium in a stream of argon using typical p arallel plate reactor. Both the deposition yield and the physical prop erties of the films strongly depended on the power input used. Soft an d semitransparent polymer-like materials, characterized by a strong de pendence of their physical properties on the energetic conditions of d eposition, were obtained at low power magnitudes. High power loads yie lded hard, glassy, dark brown to black films of relatively high electr ical conductivity (up to 4 X 10(-3) S/m) and refractive index (approxi mately 3.0), low value of optical gap (1.3 eV) and density amounting t o about 2600 kg/m(3) with the above values for a relatively large rang e remaining independent of deposition conditions. Hard films exhibited extremely homogeneous surface (down to several nm) while that of soft films was characterized by circular inhomogeneities at the level of s everal dozen nanometres. FTIR spectroscopy revealed an incorporation o f certain amount of oxygen, particularly in the case of the latter mat erials. Although there are differences in physical properties such as density or optical gap, as well as several structural differences betw een the resulting materials, the process to a large extent reminisces that of the deposition of Ge/C films from tetraethylgermanium in the s ame equipment. (C) 1998 Elsevier Science S.A. All rights reserved.