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

Abstract

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 mu m were fabricated by ELC in the super lateral-growth regime and CD at a dose of 1 x 10(13) cm(-2) or higher. Consequently, a superior field-effect mobility of 271cm(2)V(-1)s(-1) and a high on/off current ratio of 2.7 x 10(3) have been obtained for p-channel Ge TFTs with the channel width and length of both 0.5 mu m fabricated by ELC at 300mJ/cm(2) and CD at a dose of 1 x 10(13)cm(-2). The effects of ELC conditions and CD dose on the electrical characteristics of p-channel Ge TFTs were also investigated. (C) 2017 The Japan Society of Applied Physics.