Metal–nitride–oxide–semiconductor transistor

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]

In late 1967, a Sperry research team led by H.A. Richard Wegener invented the metal–nitride–oxide–semiconductor (MNOS) transistor,[9] a type of MOSFET in which the oxide layer is replaced by a double layer of nitride and oxide.[1] 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.[10]

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. ^ a b 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. Bibcode:1967ITED...14Q.629K. 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. ^ "Not just a flash in the pan". The Economist. March 11, 2006. Retrieved 10 September 2019.
  9. ^ 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. Vol. 13. p. 70. doi:10.1109/IEDM.1967.187833.
  10. ^ 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.