Highly conductive nitrogen-doped hydrogenated nanocrystalline cubic silicon carbide thin films prepared with a hot-wire chemical vapor deposition from SiH_4/CH_4/H_2/N_2 gas

摘要

Nitrogen-doped hydrogenated nanocrystalline cubic silicon carbide (nc-3C-SiC:H) thin films were prepared with a hot-wire chemical vapor deposition from SiH_4/CH_4/H_2/N_2 and the influences of the N_2 and H_2 gas flow rates on the structural and electrical properties were investigated. As the N_2 gas flow rate, F(N_2), was increased, the intake of the N atoms increased, resulting in the deterioration of the structural order of the nc-3C-SiC:H thin films. At a low H_2 gas flow rate, F(H_2), of 200 sccm, the conductivity increased with increasing F(N_2) up to 20 sccm and deteriorated with increasing F(N_2) of 20-50 sccm. The former was due to the increase in the intake of N atoms and the latter was due to the deterioration of the structural order. At a high F(H_2) of 1000 sccm, the degree of the deterioration of the structural order was low compared to that at F(H_2) of 200 sccm. The conductivity therefore improved even at high F(N_2) of 50-150 sccm. A high conductivity of 5.0 S/cm was achieved at F(N_2) = 100 and F(H_2) = 1000 sccm.