Analysis of deep-level defects on proton implanted polycrystalline silicon thin films using photoinduced current transient spectroscopy

Photoinduced current transient spectroscopy was used to investigate the defect states and capture kinetics of charge carriers for traps in low temperature polycrystalline silicon (poly-Si) films. A broad deep trap was found to be located 0.30 eV from the conduction band edge of poly-Si with capture cross section of 1:51 × 10^-15 cm². The variation of the trap capture kinetics with filling pulse time showed extended traps and linear arrays of traps, which might be grain boundary defects. Proton implantation and H-plasma treatment were used to improve poly-Si device characteristics, with traps more effectively suppressed by the former treatment. The ionized hydrogen atoms implanted into the poly-Si films are imputed to amorphize the defective poly-Si film with post-annealing enhancing re-crystallization, resulting films with fewer defects.