| 摘要 |
1,242,896. Semi-conductor devices. TEXAS INSTRUMENTS Inc. 11 Sept., 1968 [26 Sept., 1967], No. 43132/68. Heading H1K. The source and drain regions 28, 29 of an IGFET are formed by selectively removing a central portion of a single initial region formed in a substrate 19 of the opposite conductivity type by diffusion or epitaxy, e.g. into an etched recess, the portion to be removed being defined by an aperture in a relatively thick dielectric layer 23, and subsequently providing a relatively thin gate insulation layer 27 over the channel region of the substrate 19 thus exposed. Source, drain and gate electrodes 34, 36, 37 are then provided, the last-mentioned of these being insulated from the source and drain regions 28, 29 by the relatively thick dielectric layer 23. The device threshold voltage may be adjusted by diffusing a dopant into the channel region prior to deposition of the gate insulation 27. The substrate 19 is preferably of Si, suitable source and drain dopants being B, P, As or Sb. The gate insulation 27 may be of SiO 2 or SiO 2 and Si 3 N 4 . |
