Study of doping of Ge0.96 Si0.04:H films with B, and P during low frequency plasma deposition at low temperature

The films studied were grown at the temperature T_d= 160°C and doped by boron (B) and phosphorus (P) by incorporation of diborane (B₂H₆) and phosphine (PH₃), respectively, in gas mixture used for the deposition. For B-doped films changing boron concentration in gas phase C_B^gas from 0.04% to 0.06%, resulted in changing electrical characteristics: conductivity activation energy Eα and room-temperature conductivity σ_RT from E_a=0.32 to 0.52 eV and σ_RT=10^-4 to 10^-7 Ω^-1 cm^-1, respectively, suggesting compensation of electronic conductivity of the films. Further increasing C_B^gas from 0.06% to 0.14% caused a reduction of E_α from 0.52 to 0.31 eV and increasing of σ_RT from 10^-7 to 10^-4 Ω^-1 cm^-1. Similar behavior of electrical properties with boron incorporation has been reported in the B-doped Ge.H films deposited at T_d=300°C in [1]. The P doped films show continuous change in activation energy ranging from E_a=0.32 to 0.18 eV and room temperature conductivity ranging from σ_RT=2.3 × 10^-4 to 1.8 × 10^-2 Ω^-1 cm^-1 with P incorporation. Thus effective Band P-doping of Ge-Si films deposited at T_d=160°C has been demonstrated.