| 摘要 |
PURPOSE: To form a depleted semiconductor layer between a gate electrode and a dielectric by turning at least one part of the gate electrode adjacent to a gate dielectric into specified state. CONSTITUTION: A high-ohmic drift area 42 is provided on a surface 41 of a p-type semiconductor wafer 40, and the drift area 42 is composed of weakly doped domains. Such a transistor is provided with an n-type source area 43, n-type drain area 44 and p-type area 45 which surround the source area 43 and form a channel 46 inside, and a weakly p-doped gate electrode 50 is used. When a positive voltage is impressed to a drain (d) at the time of operation, the drift area 42 is depleted, a depleted layer 52 is formed inside a part 50b as well, its thickness increases from the source 43 to the drain 44, and the electric coupling between the drift area 42 and the gate electrode 50 is canceled. While depending on the doping of the polyelectrode 50b and the impressed voltage, thermally generated electrons can be stored on an interface between the polyelectrode 50b and an oxide layer 49. |
