Parametric investigation of SLS-processed poly-silicon thin films for TFT applications

Abstract The sequential lateral solidification (SLS) process has been used to crystallize thin a-Si films on quartz for thin-film transistor (TFT) applications. In this study, we have focused on the two-shot SLS microstructure, with parametric variation of the laser fluence (through the range of the SLS process window), the film thickness (250, 500, and 1000 A-thick a-Si), and the laser pulse duration (FWHM of 30, 90, and 180 ns). Following the SLS crystallization, the microstructure and orientation of the films were examined using SEM and EBSD, respectively. TFTs were fabricated in parallel to these microstructural investigations to correlate the electrical properties. Variation of the film thickness seems to have the largest effect on device performance: average mobility values of ∼288 cm 2 V −1 s −1 , ∼176 cm 2 V −1 s −1 , and ∼104 cm 2 V −1 s −1 were seen for TFTs fabricated on 1000, 500, and 250 A-thick Si films. Other varied parameters had only minor effects on the TFT characteristics.