| 摘要 |
A semiconductor device includes a buffer layer (BU), a channel layer (CH), a barrier layer (BA), and a gate electrode (GE) over a substrate (S), the gate electrode being disposed in a first opening (OA2) with a gate insulating film (GI) in between, the first opening running down to the middle of the channel layer through the barrier layer. The concentration of two-dimensional electron gas in a first region (ASB) on either side of the first opening is controlled to be lower than the concentration of two-dimensional electron gas in a second region (AF) between an end of the first region and a source (SE) or drain (DE) electrode. The concentration of the two-dimensional electron gas in the first region is thus decreased, thereby the conduction band-raising effect of polarization charge is prevented from being reduced. This prevents a decrease in threshold potential, and thus improves normally-off operability. |
