High-Performance Recessed-Channel Germanium Thin-Film Transistors via Excimer Laser Crystallization

This letter demonstrates the excimer laser crystallization (ELC) of germanium (Ge) thin films with the recessed-channel (RC) structure for high-performance p-channel Ge thin-film transistors (TFTs). Using ELC, large longitudinal grains with a single perpendicular grain boundary (GB) in the center of the recessed region were formed. This can be attributed to the lateral grain growth from un-melted Ge solid seeds in the thick region toward the complete melting recessed region during ELC. Consequently, the proposed p-channel RC-ELC Ge TFTs possessing large longitudinal grains without the perpendicular GB in the channel region exhibited a superior field-effect hole mobility of 447 cm
²
V
^-1
s
^-1
with minor performance deviation.