Effect of annealing on mechanical and optical properties of in-situ doped SiC thin films

In this paper we present the effect of the doping and annealing on the mechanical and optical properties of thin films of silicon carbide prepared by plasma enhanced chemical vapor deposition (PECVD) technique at 400 degree(s)C and using methane (CH 4 ) as a C precursor and silane (SiH 4 ) as a Si source. Diborane (B 2 H 6 ) and phosphine (PH 3 ) are employed as doping gas. A clear changes in internal stress when adding doping gas is observed. After an annealing cycle up to 650 degree(s)C the internal stress is increased for both doped and undoped films and it shifts from compressive to tensile stress region. Spectroscopic ellipsometer is used to investigate structural and optical properties of these films. The thickness of silicon carbide film is decreased for both doped and undoped films after annealing. The index of refraction and coefficient of extinction of undoped and in-situ doped silicon carbide film as a function of photon energy are obtained. Complex dielectric constant as a function of photon energy and energy bandgap of these films are calculated as well.