| 摘要 |
A semiconductor device having improved characteristics is provided. A semiconductor device has a substrate (S) and thereon a buffer layer (BU), a channel layer (CH), a barrier layer (BA), a trench (T) penetrating therethrough and reaching the inside of the channel layer (CH), a gate electrode (GE) placed in the trench (T) via a gate insulating film (GI), and drain and source electrodes (DE and SE) on the barrier layer (BA) on both sides of the gate electrode (GE). In addition, the gate insulating film (GI) has a first portion extending from an end portion of the trench (T) to a side of the drain electrode (DE) and placed at the side of the drain electrode (DE), and a second portion placed on the side of the drain electrode (DE) relative to the first portion and having a film thickness thicker than that of the first portion. The first portion is made of a single layer of an insulating film (IF2) and the second portion is made of a laminated layer of the first and second insulating films (IF1, IF2). Thus, the on-resistance can be reduced by decreasing the film thickness of the first portion at an end portion of the trench (T) on the side of the drain electrode (DE). |
