Depletion and Accumulation Mode Operation of GaAs MISFETs with nm-Thin Gate Insulating Layers Formed by UV Ozone process

摘要

UV & ozone process converts a surface of a semiconductor into an insulator and is useful to form a nm-thin and uniform thickness insulating layer. The authors fabricated Ni/oxidized-GaAs/n-GaAs (MIS) FETs by using the UV & ozone process for 120 min and 240 min at room temperature. They can be operated not only in the depletion mode but also in the accumulation mode up to 2 V (120 min) and 3 V (240 min) due to current suppressing effect of the insulator, although their current-voltage curves have hysteresis suggesting existence of interface states.