Investigation on electrical characteristics of TFTs fabricated with germanium films crystallized by atmospheric-pressure micro thermal plasma jet irradiation

Abstract

Abstract Crystalline germanium (c-Ge) is an attractive material for a thin-film transistor (TFT) channel because of its high carrier mobility and applicability to a low-temperature process. We present the electrical characteristics of c-Ge crystallized by an atmospheric-pressure micro thermal plasma jet (μ-TPJ). The μ-TPJ-crystallized c-Ge showed a maximum Hall mobility of 1070 cm2 V−1 s−1 with a hole concentration of ∼1016 cm−3, enabling us to fabricate a TFT with a field-effect mobility (μ FE) of 196 cm2 V−1 s−1 and an ON/OFF ratio (R ON/OFF) of 1.4 × 104. R ON/OFF and μ FE were dependent on the scanning speed of the TPJ, implying different types of defects were induced in the channel regions. These findings show the possibility of TPJ irradiation as a promising method for making c-Ge TFTs on insulating substrates.