Importance

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Abstract

Different thicknesses of gate oxide can be formed on a single chip in a single oxidation process by selectively implanting nitrogen into the surface of the chip in a pattern corresponding to the desired differences in gate oxide thickness. Implanting nitrogen to a silicon substrate reduces the rate at which oxide grows on the surface. Thus, by implanting different dosages of nitrogen into the surface of the substrate, thicker or thinner oxide layers can be provided. A processing chip with embedded DRAM can then be formed where the logic circuitry has a thin gate oxide and the DRAM circuitry has a thick gate oxide by implanting the higher dosage of nitrogen into the region of the chip where the logic circuits are to be formed. Different gate oxide thicknesses are then provided by exposing both the logic circuitry and the embedded DRAM section to a single thermal oxidation process.

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First Claim