Normally-Off Diamond Junction Field-Effect Transistors With Submicrometer Channel

We developed normally-off diamond junction field-effect transistors with narrow channel widths. The p-channel device with the narrowest channel width of 0.26 μm showed a large threshold voltage of -3 V. The obtained threshold voltage is consistent with the value estimated by considering the tapered channel width and the gradual-doping in the channel, which were measured by secondary ion mass spectrometry and cross-sectional transmission electron microscopy. We confirmed that the threshold voltage can be well controlled by the channel width.