A true single-transistor oxide-nitride-oxide EEPROM device

A novel single-transistor EEPROM device using single-polysilicon technology is described. This memory is programmed by channel hot-electron injection and the charges are stored in the oxide-nitride-oxide (ONO) gate dielectric. Erasing is accomplished in milliseconds by applying a positive voltage to the drain plus an optional negative voltage to the gate causing electron tunneling and/or hot-hole injection due to the deep-depletion-mode drain breakdown. Since the injection and storage of electrons and holes are confined to a short region near the drain, the part of the channel near the source maintains the original positive threshold voltage even after repeated erase operation. Therefore a select transistor, separate or integral, is not needed. Because oxide layers with a thickness larger than 60 Å are used, this device has much better data retention characteristics than conventional MNOS memory cells. This device has been successfully tested for WRITE/ERASE endurance to 10000 cycles.

[1]  G. Perlegos,et al.  A 16Kb electrically erasable nonvolatile memory , 1980, 1980 IEEE International Solid-State Circuits Conference. Digest of Technical Papers.

[2]  Discharging process by multiple tunnelings in thin-oxide MNOS structures , 1982, IEEE Transactions on Electron Devices.

[3]  S. Tanaka,et al.  A new flash E2PROM cell using triple polysilicon technology , 1984, 1984 International Electron Devices Meeting.

[4]  Fujio Masuoka,et al.  A 256K flash EEPROM using triple polysilicon technology , 1985, 1985 IEEE International Solid-State Circuits Conference. Digest of Technical Papers.

[5]  Chenming Hu,et al.  MOSFET drain breakdown voltage , 1986, IEEE Electron Device Letters.

[6]  C. Hu,et al.  A source-side injection erasable programmable read-only-memory (SI-EPROM) device , 1986, IEEE Electron Device Letters.

[7]  A hot-hole erasable memory cell , 1986, IEEE Electron Device Letters.