Long Stress (190 h) Operation of NO₂ p-Type Doped Diamond MOSFETs

In this letter, we report the constant gate bias stress characteristics of an Al2O3 layer passivated, NO2 p-type doped diamond metal-oxide-semiconductor field-effect transistor (MOSFET) for a long period of 190 h. The MOSFET exhibited stable operation throughout the period without any degradation in the drain current; rather the drain current gradually increased. Long stress time led to an increase in the gate leakage current, which can be attributed to the charge injection into the Al2O3 layer. Following the withdrawal of the stress, the gate leakage current disappeared as soon as the trapped charges in the Al2O3 layer were released and MOSFET characteristics recovered to their initial states. This study revealed the potential long-period stability and durability of diamond MOSFETs for power circuit applications.