Hydrogen-terminated diamond field-effect transistor with AlO(x) dielectric layer formed by autoxidation

Fabrication of hydrogen-terminated diamond (H-diamond) field-effect transistor (FET) with AlO(x) dielectric layer has been successfully carried out. The AlO(x) layer was formed by auto-oxidizing 6 nm Al film in the air at room temperature, and a FET without AlO(x) dielectric layer has also been fabricated for comparison. For both FETs, 100 nm Al layers were deposited as the gate electrodes, respectively. The leakage current density in FET with AlO(x) dielectric layer was four magnitude orders lower than that without AlO(x) dielectric layer at V(GS) = −5 V, indicating that AlO(x) dielectric layer could effectively reduce leakage current and prevent reverse I(D) in I(D) − V(DS) caused by defects on diamond surface. Distinct pinch-off characteristic with p-type channel was observed in I(D) − V(DS) measurement. The threshold voltage was −0.4 V at V(DS) = −15 V.