Polycrystalline SiC for a Wide‐Bandgap Emitter of Si‐HBTs

Polycrystalline β ‐ SiC grown on Si substrates from Si 2 H 6 and C 2 H 2 was investigated for a wide‐bandgap material of Si‐HBTs. We paid special attention to film composition, crystallinity, impurity redistribution, resistivity, and electrical characteristics of the SiC / Si heterojunction. Carbon concentration in the β ‐ SiC was around 50%, regardless of the Si 2 H 6 and C 2 H 2 gas flow ratio under a C 2 H 2 ‐ rich condition. Polycrystalline SiC can be grown at substrate temperatures above 850°C. Doping with phosphine, the resistivity can be reduced to 4.3 × 10 − 3 Ω · cm . Up to 30 min SiC deposition at 900°C, the profile of the underlying boron was unchanged. The value of the n ‐ SiC / p ‐ Si heterojunction diode ideality factor, n was 1.06, indicating that the current flow mechanism was diffusion. Polycrystalline SiC is a promising candidate for a wide‐bandgap material of Si‐HBTs.