Crystallization Phenomenon Induced by Proton Beam Irradiation using Large Area Ion Implantation for Polycrystalline Silicon Thin Film Transistors

Abstract

ABSTRACTCrystallization induced by proton beam irradiation using large area ion implantation at low temperature (less than 600°C) have been investigated. Phosphine gas containing hydrogen of more than 95% is discharged by RF power of 100W. Both phosphorus ions and protons are accelerated by a potential of 100kV and implanted into polycrystalline silicon (poly-Si) layers. At a range of beyond 2×1015 ions/cm2 P1 ions dose, amorphous phase is primarily formed and then changes into polycrystals again and its grain sizes grow up to 50nm in average diameter. The crystallization is found to occur simultaneously with phosphorus doping and to depend on the amount of the irradiated protons. This technique enables us to eliminate the activation annealing process for implanted dopant.