| 摘要 |
PURPOSE:To reduce drain and leak currents developed in such circumtances as a gate voltage gets near zero and an inversion gate voltage is impressed without destroying ON characteristrics by causing at least either areas of source or drain to have a structure where high and low density portions of impurities are alternately laminated. CONSTITUTION:Either of areas of source 3 and drain 4 at least has a structure where high and low density portions of impurities are alternately laminated so that the high density portion of impurities is adjacent to a channel area 2 and portions contacting a source electrode 8 and drain electrode 9 involve the high density portion of impurities respectively. For instance, the following elements: channel area 2, polycrystal-Si layer having both areas of source and drain 3 and 4, gate insulated film 5, gate electrode 6, layer insulation films 7, and source and drain electrodes 8 and 9 are mounted on an insulated substrate 1 made of glass and quartz and the like. And this configuration allows the source and drain areas 3 and 4 to be laminated in triple layers consisting of n<+> high density portions 31 and 41, non doping portions 32 and 42 as well as n<+> high density portions 33 and 43. |
