High-Density ECR-Plasma Deposited Silicon Nitride Films for Applications in III/V-based Compound Semiconductor Devices

We report on the ECR-plasma deposition and characterization of silicon nitride film exhibiting high breakdown field strength (>8 MV/cm) for applications in III/V-based compound semiconductor devices. The film deposited at 240°C contains around 13 at.% hydrogen. The hysteresis in mechanical stress, obtained from thermal cycling of the stress in film is negligible. The application of the film is being demonstrated in GaN-based HEMTs. The devices with gate length 0.3 μm and a periphery of 8x125 μm yielded cw output power density of 5.2 W/mm at 10 GHz and 35 V drain bias after passivation with the SiN film.