| 摘要 |
PURPOSE:To perform the control of a threshold voltage without a high energy accelerator in the steps nearly completed semiconductor device by containing an IGFET coated with a thin insulating film on a gate electrode and an IGFET coated with a thick insulating film in a field effect semiconductor device. CONSTITUTION:The first IGFET Q1 having a gate electrode 8 made of polycrystalline silicon coated with a thick insulating film 10 and the second IGFET Q2 having a gate electrode 9 made of polycrystalline silicon coated with a sufficiently thin insulating film 11 as compared with the thickness of the film 10 are provided on one main surface of a semiconductor substrate 1, and the impurity density C1 of the gate channel region 12 of the IGFET Q1 is different from the impurity density C2 of the gate channel region 13 of the IGFET Q2. The difference of the impurity densities C1, C2 of the regions 12, 13 is formed by forming the film 11 to cover the surface of the electrode 9 after forming source and drain metal electrodes 15-18. |
