Patent ID: 6841443

Claim:
A method for fabricating a deep trench capacitor for dynamic memory cells, wherein a trench is etched into the depth of a semiconductor substrate, wherein said trench includes a collar region adjacent a top surface of said substrate, wherein a lower region of said trench below said collar region is provided with a doping and a dielectric, and said lower region of said trench is filled with a conductive material to form an inner electrode, wherein said inner electrode and said dielectric are etched away in said collar region, and wherein a collar is formed in said collar region by a collar process, including a collar oxide deposition and etching of said collar oxide in said collar region, and wherein said inner electrode is completed in said collar region by depositing and etching conductive layers, wherein prior to said doping of said lower region a masking layer is formed in said collar region, and wherein said masking layer in said collar region is removed prior to forming of said collar by said collar process.