| 摘要 |
PURPOSE:To eliminate an apprehension of lowering insulating performance or insulator breakdown even if a high voltage is applied by forming an insulating film formed under the gate at the inner center of an annular channel to be thicker than that of a gate oxide film. CONSTITUTION:An electric field transistor associated in an integrated circuit device is formed with an n-type channel Ch on the annular surface of a p-type inner channel forming layer 8 between the inner edge of an n-type source layer 9 under a gate 10 and an n-type epitaxial layer 4 as a drain layer, and a thick insulating film 20 thicker than that of a gate oxide film 23 is formed at the annular inner center of the annular channel Ch. As a result, the thickness of a gate oxide film is sufficiently thinly formed as a conventional one to load, even if a high voltage is applied between the gate and a semiconductor surface at the time of OFF state, all the high voltage to the thick insulating film while holding the transconductance value of the transistor high thereby to completely prevent the lowering of insulating performance or insulator breakdown of the oxide film, thereby eliminating an apprehension of malfunction or impossibility of gate control. |
