Au-gated SrTiO3 field-effect transistors with large electron concentration and current modulation

We report the fabrication of low-leakage rectifying Pt and Au Schottky diodes and Au-gated metal-semiconductor field effect transistors (MESFETs) on n-type SrTiO3 thin films grown by hybrid molecular beam epitaxy. In agreement with previous studies, we find that compared to Pt, Au provides a higher Schottky barrier height with SrTiO3 . As a result of the large dielectric constant of SrTiO3 and the large Schottky barrier height of Au, the Au-gated MESFETs are able to modulate similar to 1.6 x 10(14) cm(-2) electron density, the highest modulation yet achieved using metal gates in any material system. These MESFETs modulate current densities up to similar to 68 mA/mm, similar to 20x times larger than the best demonstrated SrTiO3 MESFETs. We also discuss the roles of the interfacial layer, and the field-dependent dielectric constant of SrTiO3 in increasing the pinch off voltage of the MESFET. (C) 2014 AIP Publishing LLC.