SrSnO3 Field-Effect Transistors With Recessed Gate Electrodes

Fabrication of gate-recessed SrSnO3 (SSO) metal-semiconductor field-effect transistors (MESFETs) with Ni Schottky gates is reported on bi-layer epitaxial SSO films with a thin heavily-doped cap layer. Devices with 0.5-mu m gate length showed enhancement-mode behavior with a saturation drain current, IDSAT, of 33mA/mm and peak transconductance, g(m, max), of 65 mS/mm. The g(m, max) value is a roughly 2x improvement over control devices fabricated on single-layer films. Gate-recessed SSO MESFETs with Pt Schottky gates were also explored on the bi-layer films. Devices with 1-mu m gate length displayed I-DSAT = 133mA/mm and g(m, max) = 73 mS/mm, after thermal annealing.