Low-temperature processing and properties of nanocrystalline-SiC/crystalline Si heterojunction devices

Two series of SiC/Si heterojunction diodes were fabricated from nanocrystalline-SiC (nc-SiC) grown at 300 °C and 600 °C on Si substrates by magnetron sputtering in hydrogen-rich plasma. Both devices show good performance with a rectification ratio of 103 and 104 at ±2 V for the low and high temperature devices, respectively. The noticeable rectifying behavior of the diodes processed at low-temperature is due the very low leakage current originating from the relatively wide bandgap of the corresponding hydrogen-rich and non-compact nc-SiC layer. A additional short annealing (0.5 h) at 380 °C has allowed the drop of the ideality factor from 3.7 to 1.5, suggesting some defects recovery to a level allowing a significant contribution of the diffusion conduction mechanism to the diode forward current at low bias.