Development of p-type microcrystalline silicon carbon alloy films by the very high frequency plasma-enhanced chemical vapor deposition technique

We developed p-type muc-silicon carbon alloy thin films by the very high fr equency plasma-enhanced chemical vapour deposition technique using a SiH4, H-2, CH4, and B2H6 gas mixture at low power (55 mW/cm(2)) and low substrate temperatures (150-250 degreesC). Effects of substrate temperature and plas ma excitation frequency on the optoelectronic and structural properties of the films were studied. A film with conductivity 5.75 Scm(-1) and 1.93 eV o ptical gap (E-04) was obtained at a low substrate temperature of 200 degree sC using 63.75 MHz plasma frequency. The crystalline volume fractions of th e films were estimated from the Raman spectra, We observed that crystallini ty in silicon carbon alloy films depends critically on plasma excitation fr equency. When higher power(117 mW/cm(2)) at 180 degreesC with 66 MHz freque ncy was applied, the deposition rate of the film increased to 50.7 Angstrom /min without any significant change in optoelectronic properties.