TRENCH-DIFFUSION CORNER ROUNDING IN A SHALLOW-TRENCH (STI) PROCESS

摘要

An isolation structure on an integrated circuit is formed using a shallow trench (51) isolation process. On a substrate (10), a trench (51) is formed. A thermal anneal is performed to oxidize exposed areas of the substrate (10) to provide for round corners (42) at a perimeter of the trench (51). The thermal anneal is perfomed in an ambient where a chlorine source is added to O2 in order to minimize facets while creating the round corners (42). Oxidation time is lengthened by introducing an inert gas during the thermal anneal.