Abstract
This thesis presents the characteristics of microcrystalline silicon (μc-Si) films deposition on silicon wafer and glass substrates and the solar cell fabricated by a-Si/μc-Si films. We deposited both the μc-Si films and a-Si films by electron cyclotron resonance chemical vapor deposition(ECRCVD).The characterization of μc-Si films and a-Si films were carried out by using Raman scattering, XRD, SEM, SRP, Hall Measurement, α-step, and Four point probe. Raman scattering spectra were used to investigate the films crystallinity and crystalline fraction in the μc-Si/a-Si films. X-ray diffraction pattern(XRD) spectra were used to analyze the μc-Si/a-Si films. Fourier transform infrared(FTIR) absorption spectra were used to study the silicon-hydrogen bonding configurations and the hydrogen content of the μc-Si films. Conductivity measurements were employed to study the electrical properties of μc-Si films and a-Si films. α-step were used to measure the films thickness. Scanning electron microscopy (SEM) were used to analyze grain geometry and top morphology. Spreading Resistance Profiling (SRP) and Four point probe were used to analyze the doping concentration and Sheet resistance. In our experiments, the growth conditions to prepare the p, I, n, layers of solar cells by using ECRCVD were found. The experimental parameters used in this study are the Top/Bottom magnetic current at 60A and 100A respectively and substrate temperature at 2000C the Microwave power at 400W~700W, the process pressure at 20mtorr~60mtorr. The hydrogen dilution ratio was varied to analyze the characteristics of thin films. In addition, we also doped the films using phosphine(PH?3) and diborance(B2H6) to form the n-type and p-type silicon thin film.The experimented results show that, the maximum crystalline fraction obtained was about 70％, and the grain size in these μc-Si films have dimension of about 35.9nm when the dilution ratio was 98%. The preferred orientation of the μc-Si films were found to be<100>, and also it was observed that hydrogen content decreased with the increase of hydrogen ration. The doped concentration of N-type is about 1×1017~1×1018, P-type is about 1×1013~1×1014. In device measurement results, the Voc is about 0.41V, Isc is about 11.2mA, Fill factor is about 37%.