Preparation of undoped and phosphorus doped mc--Si:H films: effect of extended period of hydrogen plasma annealing in interrupted growth

Abstract

Interrupted growth and H-plasma annealing of stacking layers of Si:H film resulted in a significant improvement in material properties towards microcrystallization. Increase of dark conductivity and reduction of optical absorption due to extended period of hydrogen plasma exposure was noted. An associated improvement in the network structure towards crystallinity was observed by Raman, TEM and XRD studies. Highly conducting ( σ_D ~ 6 × 10^-3 s. cm^-1) undoped mc-Si:H films have been prepared at significantly low thickness of 650 Å. P-doped mc-Si:H films having conductivity ~ 26.2 S.cm^-1 were obtained from very low level of PH₃ dilution. Large number of dopants introduce additional defects at the grain boundary and inhibits the crystallization process.