ZrS<sub>2</sub> symmetrical-ambipolar FETs with near-midgap TiN film for both top-gate electrode and Schottky-barrier contact
Masaya Hamada, Kentaro Matsuura, Takuya Hamada, Iriya Muneta, Kuniyuki Kakushima, Kazuo Tsutsui, Hitoshi Wakabayashi
Abstract
Abstract ZrS 2 amibipolar MISFETs are obtained in operations with both electrons and holes. A layered polycrystalline ZrS 2 thin film was formed by sputtering and sulfur-vapor annealing on a whole surface of a 2.4 cm × 2.4 cm SiO 2 /Si substrate. The ZrS 2 FETs have Al 2 O 3 gate insulator and TiN film for both the top-gate electrode and Schottky-barrier contact, which show symmetrical I d – V gs curves with a V off of 0.4 V contributed by the TiN film with midgap work function to the sputtered ZrS 2 film. Notably, ambipolar FET operations because of both electrons and holes were successfully observed with an on/off current ratio of 250. This is an important step to realize n/p-type unipolar ZrS 2 FETs.