Method for fabricating different gate oxide thicknesses within the same chip

Abstract

A semiconductor structure having silicon dioxide layers of different thicknesses is fabricated by forming a sacrificial silicon dioxide layer on the surface of a substrate; implanting nitrogen ions through the sacrificial silicon dioxide layer into first areas of the semiconductor substrate; implanting chlorine and/or bromine ions through the sacrificial silicon dioxide layer into second areas of the semiconductor substrate where silicon dioxide having the highest thickness is to be formed; removing the sacrificial silicon dioxide layer; and then growing a layer of silicon dioxide on the surface of the semiconductor substrate. The growth rate of the silicon dioxide will be faster in the areas containing the chlorine and/or bromine ions and therefore the silicon dioxide layer will be thicker in those regions as compared to the silicon dioxide layer in the regions not containing the chlorine and/or bromine ions. The growth rate of the silicon dioxide will be slower in the areas containing the nitrogen ions and therefore the silicon dioxide layer will be thinner in those regions as compared to the silicon dioxide layer in the regions not containing the nitrogen ions. Also provided are structures obtained by the above process.

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