Metal–nitride–oxide–semiconductor transistor

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The metal–nitride–oxide–semiconductor or metal–nitride–oxide–silicon (MNOS) transistor is a type of MOSFET (metal-oxide-semiconductor field-effect transistor) in which the oxide layer is replaced by a double layer of nitride and oxide.[1] It is an alternative and supplement to the existing standard MOS technology, wherein the insulation employed is a nitride-oxide layer.[2][3] It is used in non-volatile computer memory.[4]

History[edit]

The original MOSFET (metal-oxide-semiconductor field-effect transistor, or MOS transistor) was invented by Egyptian engineer Mohamed M. Atalla and Korean engineer Dawon Kahng at Bell Labs in 1959, and demonstrated in 1960.[5] Kahng went on to invent the floating-gate MOSFET with Simon Min Sze at Bell Labs, and they proposed its use as a floating-gate (FG) memory cell, in 1967.[6] This was the first form of non-volatile memory based on the injection and storage of charges in a floating-gate MOSFET,[7] which later became the basis for EPROM (erasable PROM), EEPROM (electrically erasable PROM) and flash memory technologies.[8][9]

In late 1967, a Sperry research team led by H.A. Richard Wegener, A.J. Lincoln and H.C. Pao invented the metal–nitride–oxide–semiconductor (MNOS) transistor,[10] a type of MOSFET in which the oxide layer is replaced by a double layer of nitride and oxide.[11] Nitride was used as a trapping layer instead of a floating gate, but its use was limited as it was considered inferior to a floating gate.[12]

Charge trap (CT) memory was introduced with MNOS devices in the late 1960s. It had a device structure and operating principles similar to floating-gate (FG) memory, but the main difference is that the charges are stored in a conducting material (typically a doped polysilicon layer) in FG memory, whereas CT memory stored charges in localized traps within a dielectric layer (typically made of silicon nitride).[7]

See also[edit]

References[edit]

  1. ^ Brodie, Ivor; Muray, Julius J. (2013). The Physics of Microfabrication. Springer Science & Business Media. p. 74. ISBN 9781489921604.
  2. ^ Frohman-Bentchkowsky, D. (1970). "The metal-nitride-oxide-silicon (MNOS) transistor—Characteristics and applications". Proceedings of the IEEE. 58 (8): 1207–1219. doi:10.1109/PROC.1970.7897.
  3. ^ "Metal–nitride–oxide–semiconductor (MNOS) technology". JEDEC.
  4. ^ Ng, Kwok K. (2010). "Metal-Nitride-Oxide Semiconductor Transistor". Complete Guide to Semiconductor Devices. John Wiley & Sons, Inc. pp. 353–360. doi:10.1002/9781118014769.ch47. ISBN 9781118014769.
  5. ^ "1960 - Metal Oxide Semiconductor (MOS) Transistor Demonstrated". The Silicon Engine. Computer History Museum.
  6. ^ Kahng, Dawon; Sze, Simon Min (July–August 1967). "A floating gate and its application to memory devices". The Bell System Technical Journal. 46 (6): 1288–1295. doi:10.1002/j.1538-7305.1967.tb01738.x.
  7. ^ a b Ioannou-Soufleridis, V.; Dimitrakis, Panagiotis; Normand, Pascal (2015). "Chapter 3: Charge-Trap Memories with Ion Beam Modified ONO Stracks". Charge-Trapping Non-Volatile Memories: Volume 1 – Basic and Advanced Devices. Springer. pp. 65-102 (65). ISBN 9783319152905.
  8. ^ Bez, R.; Pirovano, A. (2019). Advances in Non-Volatile Memory and Storage Technology. Woodhead Publishing. ISBN 9780081025857.
  9. ^ "Not just a flash in the pan". The Economist. March 11, 2006. Retrieved 10 September 2019.
  10. ^ Wegener, H. A. R.; Lincoln, A. J.; Pao, H. C.; O'Connell, M. R.; Oleksiak, R. E.; Lawrence, H. (October 1967). "The variable threshold transistor, a new electrically-alterable, non-destructive read-only storage device". 1967 International Electron Devices Meeting. 13: 70. doi:10.1109/IEDM.1967.187833.
  11. ^ Brodie, Ivor; Muray, Julius J. (2013). The Physics of Microfabrication. Springer Science & Business Media. p. 74. ISBN 9781489921604.
  12. ^ Prall, Kirk; Ramaswamy, Nirmal; Goda, Akira (2015). "Chapter 2: A Synopsis on the State of the Art of NAND Memories". Charge-Trapping Non-Volatile Memories: Volume 1 – Basic and Advanced Devices. Springer. pp. 37-64 (39). ISBN 9783319152905.