Opto-electrical properties of amorphous silicon carbide thin films adjustably prepared by magnetron sputtering at room temperature

Abstract

The application of silicon carbide (SiC) thin films is extensive, and they can be prepared at room temperature using magnetron sputtering. In this study, a wide range of deposition pressures (0.5–5.5 Pa) was utilized for the sputtering of amorphous SiC thin films. With an increase in deposition pressure, not only does the oxygen content increase, but also the carbon phase changes. The oxygen ratio increases from approximately 6.8% to 20.0% as the deposition pressure rises from 0.5 Pa to 1.5 Pa, and it gradually increases further to around 25.0% as the deposition pressure rises to 5.5 Pa. When the deposition pressure is>3.0 Pa, the amorphous carbon phase transforms into diamond-like and graphite-like carbons. As a result, the optical bandgap varies from about 1.7 eV to 3.6 eV with the change in deposition pressure, while the conductivity reduces from 2.5 × 10-4 S/cm to 1.3 × 10-8 S/cm. This study provides insights into the significant impact of high deposition pressure on the material properties of sputtered SiC thin films. It demonstrates that the chemical bonding, composition, and opto-electrical properties of SiC thin films can be effectively tailored for application in optoelectronic devices.