Method for operating a NROM device
AssigneeMacronix International Co., Ltd.
InventorsCheng-Jye Liu, Tai-Liang Hsiung, Chia-Hsing Chen
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Abstract
The present invention provides a method for operating a NROM device, where the source and drain are surrounded by a heavy doping. When programming the NROM device, a more positive source bias and a more negative substrate bias is used to increase the body effect of the substrate for reducing the current require for Channel Hot Electron Injection (CHEI) programming. Furthermore, before erasing the NROM array, a pre-programming operation is performed to program every single memory cell of the NROM array to the written state for preventing over-erasing of the memory cells.
Claims17
A method for operating a NROM device comprising a gate, a source, a drain, and a substrate, wherein a surrounding of the source and the drain has an increased doping concentration, the method comprising:
- increasing body effect to decrease a programming current of CHEI by either increasing the positive bias of the source or increasing the negative bias of the substrate, or by both increasing a positive bias of the source and increasing a negative bias of the substrate;
- and
- pre-programming each cell of the NROM device to a written state before an erase operation is performed.
A method for operating a NROM device comprising a source, wherein a surrounding of the source has an increased doping concentration, the method comprising:
- increasing body effect by increasing a bias voltage of the source to reduce a programming current of CHEI;
- and
- pre-programming each cell of the NROM device to a written state before an erase operation is performed.
A method for operating a NROM device comprising a substrate, wherein the substrate comprising a heavily doped substrate with increased doping concentration, the method comprising:
- increasing body effect by increasing a negative bias of the substrate to reduce a programming current of CHEI;
- and
- pre-programming each cell of the NROM device to a written state before an erase operation is performed.
Dependencies are inferred from the claim text.