Field-effect transistor on SrTiO3 with sputtered Al2O3 gate insulator

Abstract

A field-effect transistor has been constructed that employs a perovskite-type ${\mathrm{SrTiO}}_3$ single crystal as the semiconducting channel. This device functions as an $n$ -type accumulation-mode device. The device was fabricated at room temperature by sputter-deposition of amorphous ${\mathrm{Al}}_2{\mathrm{O}}_3$ films as a gate insulator on the ${\mathrm{SrTiO}}_3$ substrate. The field-effect (FE) mobility is $\text{0.1\hspace{0.17em}}{\mathrm{cm}}^2/\mathrm{V} \mathrm{s}$ and on-off ratio exceeds 100 at room temperature. The temperature dependence of the FE mobility down to 2 K shows a thermal-activation-type behavior with an activation energy of 0.6 eV.