Effect of Ni Thickness on Off-State Currents of Poly-Si TFTs Using Ni-Induced Lateral Crystallization of Amorphous Silicon

Abstract

We have studied the effect of metal thickness for the metal-induced lateral crystallization (MILC) of a-Si on the off-state currents of poly-Si thin-film transistors (TFTs). It is found that they decrease with decreasing the Ni thickness for MILC. The Ni-MILC poly-Si TFT with the Ni area density of 1.4 X 10 14 cm -2 exhibited a field-effect mobility of 53.5 cm 2 /Vs and minimum leakage current of 0.44 pA/μm at V ds = -10 V. However, the off-state current is 6.6 pA/μm when the Ni density is 9.2 X 10 15 cm -2 , corresponding to the average Ni thickness of 10 A. It is concluded that the average Ni thickness for MILC should be less than 0.79 A to have low off-state currents from our experimental data.