Patent ID: 6335262
Filing Date: 2002-01-01
Classification: H01L,Y10S

Abstract:
A method for simultaneously fabricating different oxide thicknesses on the same semiconductor substrate which comprises:forming a sacrificial silicon dioxide layer on the surface of a semiconductor substrate; implanting nitrogen ions through the sacrificial silicon oxide layer into at least one first area of the semiconductor substrate to the oxidized while masking the other areas of the semiconductor substrate; wherein the dosage of the nitrogen ions is about 2Ã—1013 to about 2Ã—1015 atoms/cm2; and wherein the nitrogen ions are implanted at an energy of about 1 to about 15 keV; and wherein the nitrogen ions retard the oxidation rate of the semiconductor substrate; implanting second ions selected from the group consisting of chlorine ions, bromine ions, and mixtures thereof through the sacrificial silicon dioxide layer into at least one second area of the semiconductor substrate to be oxidized while masking the other areas of the semiconductor substrate; and wherein the second ions increase the oxidation rate of the semiconductor substrate; removing the sacrificial silicon dioxide layer; and then growing a layer of silicon dioxide on the surface of the semiconductor substrate wherein the growth rate of the silicon dioxide will be faster in the second area containing the second ions; and wherein the growth rate of the silicon dioxide will be slower in the first areas containing the nitrogen ions; and wherein the silicon dioxide layer will be thicker in the second areas compared to the silicon dioxide in the first areas not containing the second ions; and wherein the silicon dioxide layer will be thinner in the first compared to the silicon dioxide in the areas not containing the nitrogen ions.