Investigation and modeling of the infrared optical properties of direct current sputtered SiC films on silicon

Silicon carbide films were reactively dc sputtered onto Si(111) substrates using a silicon target in a mixed CH4/Ar atmosphere. Non-Rutherford backsca ttering using a high energy incident He+ beam (4.3 MeV for carbon analysis) and Auger electron spectroscopy were employed to analyze the composition o f the films. Structural investigations of the stoichiometric SiC films show ed that they were composed of microcrystalline and amorphous SiC. The forma tion mechanism of the microcrystalline and amorphous SiC during our deposit ion process was discussed. The optical behavior of the SiC film was studied by infrared (IR) reflectance in the range of 400-4000 cm(-1). The experime ntal IR reflectance in this range was fitted by calculating the complex die lectric function of the films based on effective medium theory, in which th e SiC films were assumed to consist of homogeneously distributed SiC (amorp hous and crystalline). The fitting of the experimental data using our model is quite satisfactory; thus the assumed model in our simulation is suitabl e for describing the IR optical properties of the sputtered SiC films. (C) 2000 American Institute of Physics. [S0021- 8979(00)07415-6].