SrSnO3 Field-Effect Transistors With Recessed Gate Electrodes

Fabrication of gate-recessed SrSnO
₃
(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-μm gate length showed enhancement-mode behavior with a saturation drain current, I
_DSAT
, of 33 mA/mm and peak transconductance, g
_m,max
, of 65 mS/mm. The g
_m,max
value is a roughly 2× 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-μm gate length displayed I
_DSAT
= 133 mA/mm and g
_m,max
= 73 mS/mm, after thermal annealing.