A memory device includes a memory array of memory cells and control logic operatively coupled to the memory array. The control logic to perform memory erase operations including: performing a true erase sub-operation by causing multiple pulse steps to be applied sequentially to a group of memory cells of the memory array, wherein each sequential pulse step of the multiple pulse steps occurs during a pulse-step period and at a higher voltage compared to an immediately-preceding pulse-step; in response to detecting an erase suspend command during a pulse step, suspending the true erase sub-operation at a start of a subsequent pulse-step period after the pulse step; and resuming the true erase sub-operation at an end of the subsequent pulse-step period.

A memory device includes a memory array of memory cells and control logic operatively coupled to the memory array. The control logic to perform memory erase operations including: performing a true erase sub-operation by causing multiple pulse steps to be applied sequentially to a group of memory cells of the memory array, wherein each sequential pulse step of the multiple pulse steps occurs during a pulse-step period and at a higher voltage compared to an immediately-preceding pulse-step; in response to detecting an erase suspend command during a pulse step, suspending the true erase sub-operation at a start of a subsequent pulse-step period after the pulse step; and resuming the true erase sub-operation at an end of the subsequent pulse-step period.

A P layer 2 having a band shape is on an insulating substrate 1. An N.sup.+ layer 3a connected to a first source line SL1 and an N.sup.+ layer 3b connected to a first bit line are on respective sides of the P layer 2 in a first direction parallel to the insulating substrate. A first gate insulating layer 4a surrounds a portion of the P layer 2 connected to the N.sup.+ layer 3a, and a second gate insulating layer 4b surrounds the P layer 2 connected to the N.sup.+ layer 3b. A first gate conductor layer 5a connected to a first plate line and a second gate conductor layer 5b connected to a second plate line are isolated from each other and cover two respective side surfaces of the first gate insulating layer 4a in a second direction perpendicular to the first direction. A third gate conductor layer 5c connected to a first word line surrounds the second gate insulating layer 4b. These components constitute a dynamic flash memory.

An n.sup.+ layer 3a connected to a source line SL at both ends, an n.sup.+ layer 3b connected to a bit line BL, a first gate insulating layer 4a formed on a semiconductor substrate 1 existing on an insulating film 2, a gate conductor layer 16a connected to a plate line PL, a gate insulating layer 4b formed on the semiconductor substrate, and a second gate conductor layer 5b connected to a word line WL and having a work function different from a work function of the gate conductor layer 16a are disposed on the semiconductor substrate, and data hold operation of holding, near a gate insulating film, holes generated by an impact ionization phenomenon or gate-induced drain leakage current inside a channel region 12 of the semiconductor substrate 1 and data erase operation of removing the holes from inside the substrate 1 and the channel region 12 are performed by controlling voltage applied to the source line SL, the plate line PL, the word line WL, and the bit line BL.

A memory device includes pages containing memory cells arranged in an array on a substrate. In each memory cell, a voltage applied to a first gate conductor layer, second gate conductor layer, third gate conductor layer, first impurity layer, and second impurity layer is controlled to form a hole group by impact ionization inside a channel semiconductor layer, and a page write operation of holding the hole group and a page erase operation of removing the hole group are performed. The first impurity layer is connected to a source line, the second impurity layer to a bit line, the first gate conductor layer to a first plate line, the second gate conductor layer to a second plate line, and the third gate conductor layer to a word line. A page erase operation is performed without inputting a positive or negative bias pulse to the bit line and the source line.

A memory device of the non-volatile type including a memory array having a plurality of memory cells organized as sectors, each sector having a main word line associated with a plurality of local word lines, each local word line coupled to the main word line by a respective local word line driver circuit, each of the local word line driver circuits consisting of a first MOS transistor coupled between the respective main word line and a respective local word line and a second MOS transistor coupled between the respective local word line and a first biasing terminal.

A memory device of the non-volatile type including a memory array having a plurality of memory cells organized as sectors, each sector having a main word line associated with a plurality of local word lines, each local word line coupled to the main word line by a respective local word line driver circuit, each of the local word line driver circuits consisting of a first MOS transistor coupled between the respective main word line and a respective local word line and a second MOS transistor coupled between the respective local word line and a first biasing terminal.

A memory device includes a common source line, a memory cell array, bit lines, and a conductive layer. The common source line is formed on a substrate. The memory cell array is formed on the common source line. The bit lines are connected to the memory cell array. The conductive layer is formed over the bit lines. In an erase operation, the memory device increases a voltage of the bit lines to an erase voltage through capacitive coupling by increasing a voltage applied to the conductive layer.

A memory device includes a common source line, a memory cell array, bit lines, and a conductive layer. The common source line is formed on a substrate. The memory cell array is formed on the common source line. The bit lines are connected to the memory cell array. The conductive layer is formed over the bit lines. In an erase operation, the memory device increases a voltage of the bit lines to an erase voltage through capacitive coupling by increasing a voltage applied to the conductive layer.

A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.