United States Patent 3,550,256
December 29, 1970

Control Of Surface Inversion Of P-And-N Type Silicon Using Dense Dielectrics
Bruce E. Deal

Filed December 21, 1967
Image of US PATENT 3,550,256

Abstract of the Disclosure

A method and device is disclosed wherein the density of fast surface states is controlled. This is accomplished by depositing a thin layer of dense dielectric (e.g. silicon nitride, silicon monoxide or silicon carbide) over selected areas of a silicon dioxide surface. The device is then thermally treated thereby reducing the density of fast surface states in areas that do not have a dielectric coating. Areas under the dielectric coating have a high density of fast surface states. The control of the density of the fast surface states enables the control and prevention of a formation of inversion layers.
Figure descriptions: cover graphic

  • Figure 1a is a capacitance-voltage curve shown in conjunction with a silicon surface depicted in diagrammatic form showing that with no fast states, the silicon surface may be inverted with application of +2 volts or more at the metal field plate.
  • Figure 1b is a capacitance-voltage curve showing the effect of fast surface charge states on inversion of a silicon surface, i.e. silicon surface is inverted only if +90 volts or greater is applied at the metal field plate.
  • Figure 3 is a section in diagrammatic form of an integrated circuit structure employing the present invention.

 Citations [54]:
2,817,613 12/1957 Mueller 3,311,756 03/1967 Nagata et al 3,387,358 06/1968 Heiman
National Museum of American History
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