OI-ELA Poly-Si TFTs for Eliminating Residual Source/Drain Junction Defects

Residual ion doping damage near the source/drain junctions of excimer laser annealed (ELA) polycrystalline silicon thin-film transistors, caused by incomplete annealing near the source/drain junction due to laser beam diffraction at the gate edge, was successfully eliminated by a new method called oblique-incidence ELA (OI-ELA). The laser beam for dopant-activation was irradiated obliquely so that the problem of incomplete annealing, due to diffraction at the gate edges, was eliminated. OI-ELA poly-Si TFTs have considerably improved electrical characteristics compared with conventional ELA poly-Si TFTs, including such properties as on-current, field effect mobility, and hot-carrier stress stability.