Image Number 7 for United States Patent #4317690.
A method of fabricating a double polysilicon MOS structure of reduced size employs local oxidation of polysilicon to define and isolate a first polysilicon layer. Prior to etching the first polysilicon layer, a first masking step defines one of the elements of the MOS transistor, such as the source. By selectively etching the first polysilicon layer, the isolation regions and then the other elements of the MOS transistor are defined. With only slight variations in the simplified process, either a plurality of one MOS transistor-one capacitor memory cells or a plurality of MOS transistors can be fabricated.
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