An efficient method is disclosed for creating different field oxide profiles in a local oxidation of silicon process (LOCOS process). The method comprises (1) forming a first portion of the field oxide with a first field oxide profile (e.g., an abrupt bird's beak profile) during a field oxide oxidation process, and (2) forming a second portion of the field oxide with a second field oxide profile (e.g., a graded bird's beak profile) during the field oxide oxidation process. A graded bird's beak profile enables higher breakdown voltages. An abrupt bird's beak profile enables higher packing densities. The method gives an integrated circuit designer the flexibility to create an appropriate field oxide profile at a desired location.