High Voltage Stress Induced in Transparent Polycrystalline Diamond Field-Effect Transistor and Enhanced Endurance Using Thick Al₂O₃ Passivation Layer

A transparent polycrystalline diamond field-effect transistor (FET) was fabricated and measured in room temperature measurements, which reveals comparatively high maximum current density and high breakdown voltage of more than 1000 V. A harsh stress environment is proposed for simple and time-effective reliability stress measurement of the FET using a method of 50 continuous cycles of 500-V voltage stress. A 400-nm-thick Al₂O₃ counter-destructive passivation layer was implemented on the FET for the stress measurements. Devices with wide gate-drain length (L_GD) retain their FET characteristics after the harsh stress measurements by only 50% reductions maximum current density.