Isolation process for semiconductor devices

摘要

An improved process is disclosed for forming the field oxide which provides isolation between adjacent devices in an integrated circuit. In one embodiment of the invention the improvement includes implanting halogen ions, and preferably chlorine ions, into the selected regions of a semiconductor substrate where field oxide is to be formed. The halogen ions are implanted before the field oxide is thermally grown and result in a localized enhancement of the oxide growth rate in the vertical direction compared to the lateral direction. For a given oxidation cycle, the halogen implant results in the growth of a thicker oxide with minimum lateral encroachment.