US Patent 8929141 Three-dimensional NAND memory with adaptive erase

Erasing memory cells in certain 3-D NAND charge-storage memory arrays is achieved by rapidly charging vertical conductors using Gate Induced Drain Leakage (GIDL) current generated in select transistors. When bit line voltage drops below its nominal value, select line voltage is controlled to maintain a constant voltage difference between bit line voltage and select line voltage thus maintaining a gate-drain voltage difference in select transistors that provides sufficient GIDL current for erase.