Patent ID: 8546268

Claim:
A method of manufacturing integrated circuit components comprising multiple devices having different gate oxidations configured to operate at different voltages, the method comprising the steps of: providing a substrate ( 100 ) having shallow trench isolation regions ( 130 , 140 ); forming a nitride cover layer ( 150 ) having a thickness less than 150 A on the substrate ( 100 ) and the shallow trench isolation regions; forming an oxide cover layer ( 160 ) having a thickness less than 150 A on the nitride cover layer ( 150 ); removing the oxide cover layer ( 160 ) and the nitride cover layer ( 150 ) from a first region (GX 5 ) of a first device configured to operate in a first voltage range; growing a first gate oxidation; removing the oxide cover layer ( 160 ) and the nitride cover layer ( 150 ) from a second region (GX 3 ) of a second device configured to operate in a second voltage range lower than the first voltage range; growing a second gate oxidation; removing the oxide cover layer ( 160 ) and the nitride cover layer ( 150 ) from a third region (GX 1 ) of a third device configured to operate in a third voltage range lower than the second voltage range; and growing a third gate oxidation; wherein: the step of removing the oxide cover layer ( 160 ) and the nitride cover layer ( 150 ) from the first region (GX 5 ) comprises: masking the second region (GX 3 ) and the third region (GX 1 ); removing the oxide cover layer ( 160 ) from the first region (GX 5 ); removing the mask from the second region (GX 2 ) and third region (GX 1 ); and removing the nitride cover layer ( 150 ) from the first region (GX 5 ); the step of removing the oxide cover layer ( 160 ) and the nitride cover layer ( 150 ) from the second region (GX 3 ) comprises: masking the first region (GX 5 ) and the third region (GX 1 ); removing the oxide cover layer ( 160 ) from the second region (GX 3 ); removing the mask from the first region (GX 5 ) and third region (GX 1 ); and removing the nitride cover layer ( 150 ) from the second region (GX 3 ); and the step of removing the oxide cover layer ( 160 ) and the nitride cover layer ( 150 ) from the third region (GX 1 ) comprises: masking the first region (GX 5 ) and the second region (GX 3 ); removing the oxide cover layer ( 160 ) from the third region (GX 1 ); removing the mask from the first region (GX 5 ) and the second region (GX 3 ); and removing the nitride cover layer ( 150 ) from the third region (GX 1 ).