FOGGY-FINE DRAIN-SIDE SELECT GATE RE-PROGRAM FOR ON-PITCH SEMI-CIRCLE DRAIN SIDE SELECT GATES
Abstract:
A memory apparatus and method of operation are provided. The apparatus includes drain-side select gate transistors for coupling to a drain-side of memory holes of memory cells and configured to retain a transistor threshold voltage. The memory holes are arranged in rows comprising strings. A control means is configured to program drain-side select gate transistors of the memory holes to an initial transistor threshold voltage using pulses increasing in magnitude by a first transistor step amount during each of a plurality of foggy loops of a foggy program operation. The control means is also configured to program the drain-side select gate transistors of the memory holes to a target transistor threshold voltage using pulses increasing in magnitude by a second transistor step amount during each of a plurality of fine loops of a fine program operation. The first transistor step amount is greater than the second transistor step amount.
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