| 摘要 |
PROBLEM TO BE SOLVED: To attain a normally-off operation type HEMT device which has low ON-resistance, can achieve a threshold voltage as high as +3 V or more and is excellent in characteristics. SOLUTION: A two-dimensional electron gas region 3g is formed in the vicinity of a hetero-junction interface of a base layer 3 and a barrier layer 4, 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 so as to have a so-called reverse-channel-type MIS transistor structure. This achieves the normally-off type HEMT element 10 having a low on-resistance. Further, when a film thickness of an insulating layer 6 is denoted as t (nm) and a relative permittivity of a substance forming the insulating layer 6 is denoted as k, a threshold voltage as high as +3 V or more can be attained by satisfying k/t≤0.85 (nm<SP>-1</SP>). COPYRIGHT: (C)2009,JPO&INPIT |
