We investigated the SiN/gallium nitride (GaN) interface properties formed by the microwave-excited plasma-enhanced chemical vapor deposition (PECVD) with SiH4/N2/H2 gases. The interface and insulating properties of SiN films on GaN formed by the microwave-excited PECVD strongly depend on SiH4 flow rate. Although the interface trap density is lower than 1011 cm-2eV-1 at the relatively high SiH4 flow rate of 1 sccm, the breakdown electric field is very low (∼ 1 MV/cm). Using the SiH4 plasma pretreatment before the stoichiometric SiN deposition, both low interface trap density and high breakdown voltage greater than 2 MV/cm are obtained. In this case, the clearly ordered Ga bonding near the SiN/GaN interface is estimated by an electron energy loss spectroscopy. The formation of SiN film on GaN using the microwave-excited PECVD is a very useful technique for the high-quality interface properties.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering