Patent ID: 7666756
Filing Date: 2010-02-23
Classification: H01L

Abstract:
1. A process of fabricating a semiconductor device comprising: providing a semiconductor substrate of a first conductivity type, the substrate not containing an epitaxial layer; forming a nitride layer over a first area of the substrate; growing an oxide layer in a second area of the substrate outside of the first area, the nitride layer substantially limiting the growth of the oxide layer in the first area so as to form an opening in the oxide layer, with a bird's beak formation being formed in the oxide layer under a peripheral area of the nitride layer; removing the nitride layer; and implanting a dopant of a second conductivity type into the substrate, the second conductivity type being opposite in electrical polarity to the first conductivity type, the dopant forming an isolation region of the second conductivity type, a portion of the isolation region being buried in the substrate below the opening in the oxide layer so as to form an enclosed region of the first conductivity type, the isolation region curving upward towards the surface of the substrate below the bird's beak formation and meeting the surface of the substrate at an inside edge of the oxide layer formed by the tip of the bird's beak formation, the isolation region electrically isolating the enclosed region of the substrate from a remainder of the substrate.