Excimer laser annealed poly-Si thin film transistor with self-aligned lightly doped drain structure

Abstract

We have made an excimer laser annealed poly-Si thin film transistor (TFT). The stress of the poly-Si films crystallized by excimer laser annealing is studied by Raman spectroscopy. The transverse-optic phonon frequency is independent of the excimer laser energy, but dependant on the precursor a-Si film thickness. The nMOS TFT with a self-aligned lightly doped drain (LDD) structure shows low leakage current. The large leakage current of the pMOS TFT with non-LDD structure is reduced by the off-state stress. The gate to channel capacitance as a function of gate voltage for nMOS TFT shows the characteristic parallel shift of the capacitance–voltage curves with frequency variation.