Plane and block location dependent voltage biases in NAND memory
The memory device includes a chip with at least one voltage pump and a plurality of planes. The planes have arrays of memory cells that can be programmed and erased. At least some of the planes are at different distances from the at least one voltage pump. The memory device further includes control circuitry that is configured to program and erase the memory cells. The control circuitry is further configured to supply at least one voltage to a selected plane of the plurality of planes during a programming operation or an erase pulse and adjust the at least one voltage that is supplied to the selected plane by a parameter that is determined based on a distance between the selected plane and the at least one voltage pump.
1 . A method of operating a memory device, comprising the steps of:
preparing a chip that includes an erase voltage pump and a plurality of planes, each of the planes having arrays of memory cells that can be programmed and erased, and at least some of the planes being at different distances from the erase voltage pump, wherein the erase voltage pump is configured to supply an erase voltage;
adjusting at least one parameter of the erase voltage based on a distance between the selected plane and the erase voltage pump; and
supplying, from the erase voltage pump, the erase voltage to the selected plane of the plurality of planes during an erase operation.
2 . The method as set forth in claim 1 , wherein the at least one parameter is a ramp rate.
3 . The method as set forth in claim 1 , wherein the at least one parameter includes a bias voltage.
4 . The method as set forth in claim 3 , wherein the erase voltage pump includes a VERA pump and wherein the bias voltage is determined based on the distance between the selected plane and the VERA pump.
5 . The method as set forth in claim 4 , wherein the erase voltage that is supplied to the selected plane includes an erase voltage VERA that is supplied by the VERA pump to the selected plane and wherein the erase voltage VERA is adjusted by an erase bias voltage that is determined based on a distance between the selected plane and the VERA pump.
6 . The method as set forth in claim 4 , wherein the erase voltage that is adjusted by the bias voltage is supplied to at least one select gate transistor in a memory block within the selected plane during an erase operation.
7 . The method as set forth in claim 4 , wherein the erase voltage that is adjusted by the bias voltage is supplied to a plurality of word lines in a memory block within the selected plane during an erase operation.
8 . The method as set forth in claim 1 , wherein the erase voltage pump includes a VPGM pump and the bias voltage is determined based on a distance between the selected plane and the VPGM pump.
9 . The method as set forth in claim 8 , wherein the erase voltage that is supplied to the selected plane includes a VPGM voltage that is supplied by the VPGM pump and wherein the VPGM voltage is adjusted by a VPGM bias voltage that is based on the distance between the selected plane and the VPGM pump.
10 . A memory device, comprising:
a chip that includes an erase voltage pump and a plurality of planes, each of the planes having arrays of memory cells that can be programmed and erased, and at least some of the planes being at different distances from the erase voltage pump, wherein the erase voltage pump is configured to supply an erase voltage;
control circuitry configured to program and erase the memory cells, the control circuitry being configured to;
adjust at least one parameter of the erase voltage based on a distance between the selected plane and the erase voltage pump; and
supply, from the erase voltage pump, the erase voltage to a selected plane of the plurality of planes during an erase operation.
11 . The memory device as set forth in claim 10 , wherein the parameter is a ramp rate.
12 . The memory device as set forth in claim 10 , wherein the parameter is a bias voltage.
13 . The memory device as set forth in claim 12 , wherein the erase voltage pump includes a VERA pump and wherein the bias voltage is determined based on the distance between the selected plane and the VERA pump.
14 . The memory device as set forth in claim 13 , wherein the erase voltage that is supplied to the selected plane includes an erase voltage VERA that is supplied by the VERA pump to the selected plane and wherein the erase voltage VERA is adjusted by an erase bias voltage that is determined based on a distance between the selected plane and the VERA pump.
15 . The memory device as set forth in claim 12 , wherein the erase voltage pump includes a VPGM pump and the bias voltage is determined based on a distance between the selected plane and the VPGM pump.
16 . The memory device as set forth in claim 15 , wherein the erase voltage that is supplied to the selected plane includes a VPGM voltage that is supplied by the VPGM pump and wherein the VPGM voltage is adjusted by a VPGM bias voltage that is based on the distance between the selected plane and the VPGM pump.
17 . An apparatus, comprising:
a chip that includes a VERA voltage pump and a VPGM voltage pump and a plurality of planes, each of the planes having arrays of memory cells that can be programmed and erased, and at least some of the planes being at different distances from the VERA voltage pump and from the VPGM voltage pump;
a controlling means for programming and erasing the memory cells, the controlling means being configured to;
supply a VPGM voltage to a selected plane of the plurality of planes during a programming operation and being configured to supply a VERA voltage to the selected plane during an erase operation;
adjust the VPGM voltage that is supplied to the selected plane during the programming operation by a VPGM bias voltage that is determined based on a distance between the selected plane and the VPGM voltage pump; and
adjust the VERA voltage that is supplied to the selected plane during the erase operation by a VERA bias voltage that is determined based on a distance between the selected plane and the VERA voltage pump.
18 . The apparatus as set forth in claim 17 , wherein a magnitude of the VPGM bias voltage increases with increasing distance between the selected plane and the VPGM pump and wherein a magnitude of the VERA bias voltage increases with increasing distance between the selected plane and the VERA pump.