Controlling Anion Composition at Metal–Insulator–Semiconductor Interfaces on III–V Channels by Plasma Processing

The anion composition of InGaAs surfaces was controlled by using plasma processing, and its effects on the metal–insulator–semiconductor (MIS) properties were investigated. On-line Auger electron spectroscopy showed that H2 plasma cleaning on InGaAs effectively reduced the surface oxides and removed approximately one monolayer of As. Following this by plasma nitridation successfully introduced approximately two monolayers of N; however, the nitrided layer also contained an oxide component. Although the electrical properties of the Al2O3/InGaAs capacitors were degraded by H2 plasma processing, subsequent nitridation restored well-behaved MIS characteristics to the devices. The channel mobility of MIS field-effect transistors with a nitride interface was higher than that of the control device.