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 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.

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