(Invited, Digital Presentation) Evaluation of Polycrystalline-Si_1-XGe_x Thin-Film Transistors Grown Laterally on a Glass Substrate Using a Continuous-Wave Laser

Abstract

This study aims to understand the performance of continuous-wave laser lateral crystallization (CLC) poly-Si1-xGex TFTs. The transfer characteristics of n-ch CLC poly-Si1-xGex TFTs revealed that the threshold voltages shifted in the positive direction compared with those of CLC poly-Si TFTs with increasing Ge concentration. The characteristics of CLC n-ch poly-Si1-xGex TFTs can be explained by the formation of acceptors. For p-ch TFTs, the transfer characteristics of CLC poly-Si1-xGex TFTs exhibited a larger Ioff than those of CLC poly-Si TFTs. The Ion/Ioff ratio is small for p-ch parallel CLC poly-Si1-xGex TFTs and is weakly dependent on the gate length. In contrast, p-ch perpendicular CLC poly-Si1-xGex TFTs exhibit large Ion/Ioff values for long gate lengths. The variation in the Ion/Ioff ratio of p-ch CLC poly-Si1-xGex TFTs according to the parallel or perpendicular and long or short gate length is explained by Ge segregation along the grain boundary, resulting in the formation of a high-concentration p-type conduction region along the grain boundary, which connects the SD regions.

Performance evaluation of polycrystalline Si1−xGex thin-film transistors fabricated by continuous-wave laser lateral crystallization on glass substrates

“…© 2024 The Japan Society of Applied Physics poly-Si 1−x Ge x thin film increased as the Ge content increased, and the grain boundaries became nearly parallel to each other. [28][29][30][31][32][34][35][36] The Raman scattering spectra of the CLC poly-Si 1−x Ge x (x = 0, 0.05, 0.1, and 0.3) films are shown in Fig. 3.…”

“…This is consistent with our previous study for x = 0.1. 32) Notably, Ge also agglomerated at the poly-Si 1−x Ge x /glass interface.…”