Abstract
In this thesis, device quality amorphous silicon and polycrystalline silicon thin films were investigated for fabricating SPA solar cells by using ICP-CVD with internal low-inductance antenna (LIA). For polycrystalline silicon thin films, we observed that 98% of hydrogen dilution ratio with a SiH4 flow rate of 2 sccm and H2 flow rate of 98 sccm are suitable. Furthermore, higher power of 3000 W and higher temperature of 400℃ and 10mT process pressure increased the crystalline volume fraction Xc of poly-Si films. Annealing the substrates at 350℃ in vacuum chamber for 30 minutes before depositing the films also could enhance the quality of poly-Si film and the highest Xc obtained was 82.63% on the glass substrate. The highest conductivity of n-type poly-Si thin-film which was obtained with the doping gas PH3 diluted in 99% H2, was1.916 Ω-1-cm-1. Hydrogenated amorphous silicon films were fabricated by tuning the process parameters to lower power of 1500 W, lower temperature of 200℃, and lower hydrogen dilution of 77%, and the band gap obtained was 1.75 eV, and the Raman spectra of this film showed a peak at 480cm-1. In the case of p-type amorphous silicon thin films, the conductivity obtained was 0.315 Ω-1-cm-1. For the highest band gap of 1.705 eV with the doping gas B2H6 diluted in 99.5% H2. We fabricated the single heterojunction thin-film Si solar cell with poly-Si and a-Si:H absorber layers (SPA) and the highest efficiency of 2.4 % was obtained. After replacing the p-type amorphous layer and absorber amorphous layer with higher band gap deposited in NTCU, efficiency improved to 3.24 %.