US Patent 10121536 Semiconductor memory device and memory system

A semiconductor memory device includes a first memory cell array including a first memory cell that is capable of holding two or more bits of data including at least a first bit and a second bit, a second memory cell array including a second memory cell that is capable of holding two or more bits of data including at least a first bit and a second bit, a first word line electrically connected to a gate of the first memory cell, and a second word line electrically connected to a gate of the second memory cell. In a read operation, at least first, second, and third voltages are applied successively to both the first word line and the second word line to read a first page including the first bit of the first memory cell and a second page including the second bit of the second memory cell.