Coupling of different leakage paths between trench capacitors

Out from various cell concepts under investigation for the 16 and 64 Megabit DRAM generation the depletic type trench cell is still favoured because of its low process complexity. However, further shrinking of this cell concept, which is been widely used for the 4 Megabit DRAM, may result in leakage problems between neighbouring trench capacitors. The isolation of a modified version of this cell type, the SSP cell, has been investigated by numerical simulation as a function of well implantation dose and the trench to trench separation in the case of three closely spaced trench capacitors.