Field effect transistor having electrode coated sequentially by oxide layer and nitride layer and method for manufacturing the same

Abstract

A field effect transistor includes a substrate, an epitaxial layer, a remnant-oxide layer, an electrode, a surrounding-oxide layer, a surrounding-nitride layer, a gate oxide layer, a gate, a P-body region, a source region, an interlayer dielectric and a source electrode. The epitaxial layer on the substrate has a trench having a sidewall and a bottom. The electrode inside the trench is coated subsequently by the surrounding-oxide layer, the surrounding-nitride layer and the remnant-oxide layer. The gate formed on the gate oxide layer is separated from the electrode sequentially by the gate oxide layer, the surrounding-nitride layer and the surrounding-oxide layer. The P-body region and the source region, formed at the epitaxial layer, are separated from the gate by the gate oxide layer. The interlayer dielectric covers the source region and the gate. The source electrode covers the P-body region and the interlayer dielectric, and contacts the source region.