High-Performance Germanium Thin-Film Transistors With Single-Crystal-Like Channel via Continuous-Wave Laser Crystallization

This letter reports of the fabrication of high-performance p-channel polycrystalline germanium (poly-Ge) thin-film transistors (TFTs) using continuouswave laser crystallization (CLC). During the CLC process, the direction of crystallization matches the direction of laser scanning due to a strong temperature gradient in the melting region. This makes it possible to fabricate high-quality poly-Ge thin films with 1-D longitudinal grains as large as 2 μm × 20 μm. We fabricated the proposed p-channel CLC Ge TFTs with channel width of 0.7 μm and a channel length each of 0.7 μm. Consequently, the proposed p-channel CLC Ge TFTs with single-crystal-like channel fabricated on a longitudinal grain with biaxial tensile strain achieved a superior field-effect mobility of 1014.9 cm
²
/V-s.