Programming dummy memory cells in erase operation to reduce threshold voltage downshift for select gate transistors

Abstract

Apparatuses and techniques are described for reducing charge loss in a select gate transistor in a memory device. In one aspect, a dummy memory cell adjacent to a select gate transistor is weakly programmed during an erase operation by applying a program pulse to the dummy memory cell. The program pulse can be applied after an erase bias is applied to the memory cells and before an erase-verify test is performed, in one approach. The program pulse can be applied during the setup of the voltages for the erase-verify test. The magnitude of the program pulse can be increased in successive erase loops of an erase operation as the magnitude of a substrate voltage is also increased. The magnitude of the program pulse can also be set as an increasing function of a number of program-erase (P-E) cycles.