Control of strain gradient in doped polycrystalline silicon carbide films through tailored doping

Abstract

Polycrystalline 3C-SiC (poly-SiC) films are deposited by low-pressure chemical vapor deposition on Si substrates using 1,3-disilabutane and are in situ doped by NH3. Microstrain gauges and cantilever beam arrays are fabricated to study the doping effect on average residual strain and strain gradient. A bi-layer deposition scheme consisting of films with different residual strains due to differing doping content is developed to minimize the strain gradient without compromising the electrical resistivity of the deposited film. In this way, a 3 µm thick poly-SiC film with a strain gradient of 5 × 10−5 µm−1 and a resistivity of 0.024 Ω cm is achieved.