Electrical Properties of H‐Diamond Field Effect Transistor With ZrO ₂ /HfO ₂ Stacked‐Gate Deposited by Electron Beam

Electrical properties of H‐diamond field effect transistor with ZrO ₂ /HfO ₂ stacked gate deposited by electron beam have been investigated in this letter. Due to the fixed positive charge in ZrO ₂ contact layer, both devices exhibit normally‐off operation. Compared with ZrO ₂ monolayer gate sample, the ZrO ₂ /HfO ₂ stacked‐gate device showed an order of magnitude improvement in gate leakage current (~3.5 × 10 ⁻⁶  A/cm ² at V _GS = −5 V), on/off ratio (10 ⁹ ), SS (138 mV/dec @ V _GS = −0.2 V) and a relatively higher I _Dmax of −50 mA/mm at V _GS = −6 V. Therefore, the ZrO ₂ /HfO ₂ stacked‐gate is a promising gate dielectric to improve the performance of H‐diamond FETs.