Patent ID: 6822281
Filing Date: 2004-11-23
Classification: H01L

Abstract:
A trench cell for storing digital information, comprising:a semiconductor substrate of a first conductivity type, said semiconductor substrate defining a trench hole having: a lower region; a surface; and an upper region with a sidewall section; a storage capacitor being formed in said semiconductor substrate in said lower region of said trench hole, said storage capacitor having an inner electrode, a dielectric intermediate layer, and an outer electrode; a vertical selection transistor being formed in said semiconductor substrate in said upper region of said trench hole at said sidewall section, said vertical selection transistor having: an upper source/drain doping region and a lower source/drain doping region of a second conductivity type; a gate electrode; an insulator layer; and a channel region being disposed between said upper source/drain doping region and said lower source/drain doping region, said channel region being isolated from said gate electrode by said insulator layer; a bit line running in a direction perpendicular to said trench hole, said bit line being connected to said upper source/drain doping region; a word line running perpendicular to said trench hole and transverse with respect to said bit line, said word line being connected to said gate electrode; said lower source/drain doping region being connected to one of said inner and outer electrodes; and a doping region of said first conductivity type being adjacent said surface, said doping region being disposed in said semiconductor substrate opposite said vertical selection transistor viewed in said direction of said bit line adjacent to said sidewall section of the trench hole.