Hydrogen passivation on Sequential Lateral Solidified poly-Si TFTs

The field effect mobility is sufficiently and impressively improved by increasing the passivation time from 15min to 50min, denoting that SLS films allow quite efficient passivation of defects. The present work investigates the effects of hydrogen passivation on the electrical performance of Sequential Lateral Solidified (SLS) poly-Si TFTs by analyzing the dependence of electrical properties on temperature. Under hydrogenation the density of states in the band gap is sufficiently reduced. Analysis of the thermally activated parameters reveals that although previous studies suggest poor passivation of tail states, in SLS TFTs the passivation rate is significantly improved. Moreover, devices subjected to hydrogenation for a longer time exhibit a higher threshold temperature for the thermally activated mechanisms and a lower threshold voltage temperature shift (ΔVT). It is also found that mobility is almost doubled, which taken into account that previously reported values in laser crystallized films are of the order of 10%, is quite a notable result.