United States Patent 3,519,897
July 7, 1970

Semiconductor Surface Inversion Protection
J.F. Ferrell

Filed October 31, 1968
Image of US PATENT 3,519,897

Abstract of the Disclosure

A novel metal-insulator-semiconductor capacitor device and method of manufacture wherein means are provided for narrowly defining the boundaries of the inversion region lying beneath the metallic electrode disposed on the surface of the semiconductor chip. An impurity region highly doped with an appropriate dopant is provided around the intentional inversion region for delimiting the area thereof as well as prohibiting an unintentional expansion of this area due to spurious inversion of the substrate surface caused by accumulation of surface charge on the overlying dielectric.
Figure descriptions: cover graphic

  • Figure 1 is a plan view of a prior are metal-insulator-semiconductor capacitor, illustrating the effects of surface charge inversion.
  • Figure 2 is a cross-section of the capacitor of Figure 1, taken along the line 2-2, and showing the substrate in its inverted condition.
  • Figures 3 through 7 illustrate exemplary operative steps which may be followed in manufacturing a metal-insulator-semiconductor capacitor in accordance with the subject invention.
  • Figure 8 is a plan view of a metal-insulator-semiconductor capacitor, illustrating the novel features of the present invention.
  • Figure 9 is a cross-section of the capacitor of Figure 8, taken along the line 9-9, illustrating the inverted substrate.

 Citations [54]:
3,197,681 07/1965 Broussard 3,226,612 12/1965 Haenichen 3,338,758 08/1967 Tremere 3,428,875 02/1969 Snow
National Museum of American History
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