High Temperature Operation of Boron-Implanted Diamond Field-Effect Transistors

Abstract

Diamond field effect transistors (FETs) with Pt or Al Schottky gate electrodes were fabricated on high-quality boron (B)-implanted layers formed by combining ion-implantation and high-pressure and high-temperature annealing. The high temperature characteristics of these FETs were examined. Pt-gate B-implanted diamond FETs showed maximum drain current (IDS) of 0.16 mA/mm at gate voltage of -2 V and drain voltage of -20 V at 25 °C. The IDS increased as temperature increased because of the activation of boron, and it showed maximum value of 3.9 mA/mm at ∼200 °C. Al-gate FETs showed similar temperature dependence of IDS, though the operation temperature and IDS were higher than those of Pt-gate FETs. High-temperature operation of the B-implanted diamond FETs was possible above 550 °C without severe drain bulk leakage, though the maximum IDS gradually decreased as temperature increased because of drain bulk leakage above 300 °C.