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 grainswith 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 unmelted 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 holemobility of 447 cm(2)V(-1)s(-1) with minor performance deviation.