AlGaN/GaN metal oxide semiconductor high electron mobility transistor using liquid-phase deposited strontium titanate

Abstract

SrTiO3 thin films were deposited on AlGaN/GaN wafer by a simple, low-temperature liquid-phase deposition (LPD) method, and applied as the gate dielectric in metal oxide semiconductor high electron mobility transistor (MOSHEMT). X-ray diffraction and electrical characteristics were measured to investigate the film phase and leakage current. AlGaN/GaN MOSHEMTs with 20nm-thick SrTiO3 as the gate dielectric were also fabricated. Compared with its counterpart HEMT, MOSHEMT shows lower leakage current and larger breakdown voltage. The suppressed gate leakage current improves both Ion/Ioff ratio and subthreshold slope. Larger maximum drain current density could be achieved with higher Von in the MOSHEMT. Flatter transconductance and wider gate voltage swing of the MOSHEMT demonstrate better device linearity. The lower low-frequency noise is obtained due to the lower surface states.