High temperature operation of Boron-implanted diamond field-effect transistors

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 (I_DS) of 0.16mA/mm at gate voltage of -2 V and drain voltage of -20V at 25°C. The I_DS increased as temperature increased because of the activation of boron, and it showed maximum value of 3.9mA/mm at ∼200 °C. Al-gate FETs showed similar temperature dependence of I_DS, though the operation temperature and IDS were higher than those of Ptgate FETs. High-temperature operation of the B-implanted diamond FETs was possible above 550 °C without severe drain bulk leakage, though the maximum I_DS gradually decreased as temperature increased because of drain bulk leakage above 300 °C.