| 20090050938 | MIS GATE STRUCTURE TYPE HEMT DEVICE AND METHOD OF FABRICATING MIS GATE STRUCTURE TYPE HEMT DEVICE - A normally-off operation type HEMT device excellent in characteristics can be realized. A two-dimensional electron gas region is formed in a periphery of a hetero-junction interface of a base layer and a barrier layer, so that access resistance in an access portion, that is, between a drain and a gate and between a gate and a source is sufficiently lowered, and at the same time, a P-type region is formed immediately under the gate. This realizes a normally-off type HEMT device having a low on-resistance. Further, when a film thickness of an insulating layer is defined as t (nm) and a relative permittivity of a substance forming the insulating layer is defined as k, a threshold voltage as high as +3 V or more can be attained by satisfying k/t≦0.85 (nm | 02-26-2009 |
