Effects of doping levels at source and drain regions on the performance of a-Si FET
The transfer characteristics of a-Si FETs are remarkably improved by adopting the phosphorus doped n+-layer at the source and drain contacts. Excess doping of phosphorus, however, causes degradation in the transfer characteristics after heat treatment. The optimum doping level is obtained by depositing the n+-layer at 1 to 5×10−3 molar ratios of PH3/SiH4.