Production of a trench dynamic random access memory cell in a semiconductor substrate involves forming pad nitride on substrate and ion etching trench vertically to first depth, depositing nitride layer in the trench and further treating

摘要

Production of a trench dynamic random access memory cell includes: forming pad nitride on substrate and ion etching trench; depositing nitride layer in trench; filling trench with polysilicon filling; back etching filling; forming nitrided oxide collar or oxide layer; ion etching; dissolving filling trench and nitride etching; extending trench; and forming trenched plate on trench side walls. Production of a trench dynamic random access memory (DRAM) cell in a semiconductor substrate comprises: forming a pad nitride on the surface of the substrate and ion etching a trench vertically to a first depth; depositing a nitride layer (20) in the trench; filling the trench with a polysilicon filling (21); back etching the filling to a collar depth; oxidizing to convert the exposed nitride layer into a nitrided oxide collar or depositing an oxide layer on the nitride layer; ion etching to open the base oxide; dissolving the filling trench and nitride etching selectively to the oxide; extending the trench in the horizontal direction by etching the lower trench side walls and the base during masking of the upper side walls; forming a trenched plate on the base of the trench side walls; forming a node dielectric in the trench; filling the trench with a polysilicon filling; back etching the filling; depositing a collar oxide; ion etching to open the base; filling the trench with a polymer filling; and chemical-mechanical polishing the substrate. Preferred Features: The pad nitride is silicon nitride. The trench filling is amorphous silicon, silicon-germanium or germanium.