Annealing Behavior after Ion Shower Doping for the Fabrication of LTPS-TFTs

Ion shower doping with a main ion source of P2Hx using a source gas mixture of PH3/H2 was conducted on excimer-laser-annealed (ELA) poly-Si. The amount of as-implanted damage was observed to increase with acceleration voltage. The measured values of as-implanted damage using a UV-transmittance was found to correlate well with the ones calculated using TRIM-code simulation. After activation annealing the sheet resistance generally decreases as the acceleration voltage increases. It, however, increases as the acceleration voltage increases under the conditions of severe doping and low temperature annealing. Results of UV-transmission Spectroscopy and Hall measurements revealed that uncured damage seems to be responsible for the rise in sheet resistance.