Amorphous and microcrystalline silicon films deposited by hot wire cell method: application to silicon based thin film solar cells

Hot Wire Cell method has been developed in order to grow a-Si and /spl mu/c-Si thin films with relatively high growth rates of 0.4-3.0 nm/s at a low substrate temperature of about 200/spl deg/C. It was found that the peak at 2100 cm/sup -1/ which originates from Si-H, bonding in the infrared absorption spectra could be dramatically reduced at a low deposition pressure of 10 mTorr. Besides, it was found by SIMS analysis that the concentrations of O and C atoms could be reduced to the order of 10/sup 18/ cm/sup -3/ for a-Si and 10/sup 20/ cm/sup -1/ for /spl mu/c-Si, respectively, at low deposition pressures of 3-10 mTorr. The conversion efficiency of 7.5% and 3.3% were achieved for superstrate-type a-Si and /spl mu/c-Si solar cells with the deposition rate of 0.4-0.5 nm/s under AM1.5 insulation, respectively.