Method of manufacturing a minimum bird's beak recessed oxide isolation structure.

摘要

A method for making a dielectric isolation pattern in integrated circuit structure is described. A monocrystalline silicon body (10, 20) is provided. There is formed thereon a layered structure (22, 24, 26) of silicon dioxide, polycrystalline silicon and silicon nitride, in that order. The layers are patterned to form openings in the structure at the areas where it is desired to form an oxide isolation pattern within the monocrystalline silicon body. If it is desired to form a semi-recessed oxide isolation there will be no etching of the monocrystalline silicon body in the openings. Should it be desired to form a full recessed oxide isolation there is etching of the monocrystalline silicon to a desired depth to form a substantially planar top surface of the monocrystalline with the recessed dielectric oxide isolation. The body is then oxidized until the desired oxide isolation pattern penetrates to the desired depth within the silicon body. Through a reduced silicon oxide layer (22) and by adding the polycrystalline silicon layer (24) a substantially reduced lateral oxidation and thus smaller beak length is achieved allowing higher integration density.