Leakage mechanisms in the trench transistor DRAM cell

摘要

The authors discuss a band-to-band tunneling mechanism in the trench transistor cell (TTC), which is used in Texas Instruments' 4-Mbit DRAM. This effect should be operative in the class of trench cells in which the charge is stored inside the trench and the substrate forms a capacitor plate. This effect does not compromise the functionality of the cell; in fact, it has the potential of improving the long-term reliability of the cell by preventing electrical overstress of the trench capacitor oxide.