Lateral large-grained low-temperature polycrystalline silicon-germanium thin-film transistors on glass substrates

Lateral large-grained (LLG) polycrystalline silicon
_1-x
germanium
_x
(poly-Si
_1-x
Ge
_x
) thin-film transistors (TFTs) with x = 0, 0.05, 0.1, and 0.3 were fabricated on glass substrates using a maximum processing temperature of 550°C. Silicon dioxide (SiO
₂
) was used as the gate dielectric, and the performance of the TFTs was evaluated in terms of mobility and subthreshold swing value (s-value). The LLG poly-Si
_1-x
Ge
_x
films were crystallized by a diode-pumped solid-state continuous-wave laser with a wavelength of 532 nm. It was observed that the performance of poly-Si
_1-x
Ge
_x
TFTs degraded with increasing Ge concentration despite the increasing grain length of the poly-Si
_1-x
Ge
_x
. The Ge-dependent degradation mechanism of poly-Si
_1-x
Ge
_x
TFTs is thought to be caused by the charge state at the poly-Si
_1-x
Ge
_x
/gate-SiO
₂
interface.