High-performance p-channel thin-film transistors with lightly doped n-type excimer-laser-crystallized germanium films.

High-performance polycrystalline-germanium (poly-Ge) thin-film transistors (TFTs) fabricated with lightly doped Ge thin films by excimer laser crystallization (ELC) and counter doping (CD) have been demonstrated. High-quality n-type Ge thin films with a grain size as large as 1 µm were fabricated by ELC in the super lateral-growth regime and CD at a dose of 1 × 10¹³ cm⁻² or higher. Consequently, a superior field-effect mobility of 271 cm² V⁻¹ s⁻¹ and a high on/off current ratio of 2.7 × 10³ have been obtained for p-channel Ge TFTs with the channel width and length of both 0.5 µm fabricated by ELC at 300 mJ/cm² and CD at a dose of 1 × 10¹³ cm⁻². The effects of ELC conditions and CD dose on the electrical characteristics of p-channel Ge TFTs were also investigated. [ABSTRACT FROM AUTHOR]