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-volatilecomputer memory.[4]
The first silicon dioxide transistors were developed by Frosch and Derick in 1957 at Bell Labs.[5]
In late 1967, a Sperry research team led by H.A. Richard Wegener invented the metal–nitride–oxide–semiconductor (MNOS) transistor,[6] 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.[7]
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).[8]
^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.
^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. ISBN9781118014769.
^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.
