P-type polycrystalline Si films prepared by aluminum-induced crystallization and doping method

P-type polycrystalline silicon films were prepared by aluminum-induced crys tallization and doping. The starting material was hydrogenated amorphous si licon prepared by plasma-enhanced chemical vapor deposition on glass substr ates. An aluminum layer with a different thickness was evaporated on the a- Si:H. Conventional thermal annealing was performed for crystallization. X-r ay diffraction and secondary ion mass spectroscopy measurements were used t o study the structural change and the Al profile in the films. Resistivity, Hall mobility, carrier concentration and spectral optical transmittance we re measured to evaluate the electrical and optical properties of the films. Results showed that poly-Si films could be obtained by annealing a-Si:H fi lms at 450 to 550 degreesC for 5 to 60 min. In spite of a relatively high o xygen impurity content in the films, they are p-type, with low resistivity, high Hall mobility and carrier concentration of 0.06 (Omega .cm), 20 Cm-2/ Vs and similar to 10(18) cm(-3), respectively. This technique has great pot ential for solar cell mass production using low-cost glass substrates.