Following the invention of the [[MOSFET]] by [[Mohamed Atalla]] and [[Dawon Kahng]] at [[Bell Labs]] in 1959, they demonstrated MOSFET technology in 1960.<ref name="computerhistory">{{cite journal|url=https://www.computerhistory.org/siliconengine/metal-oxide-semiconductor-mos-transistor-demonstrated/|title=1960 - Metal Oxide Semiconductor (MOS) Transistor Demonstrated|journal=The Silicon Engine|publisher=[[Computer History Museum]]}}</ref> They [[Semiconductor device fabrication|fabricated]] both [[PMOS logic|PMOS]] and NMOS devices with a [[10 µmμm process|20{{nbsp}}µmμm process]]. However, the NMOS devices were impractical, and only the PMOS type were practical working devices.<ref name="Lojek">{{cite book |last1=Lojek |first1=Bo |title=History of Semiconductor Engineering |url=https://archive.org/details/historysemicondu00loje_697 |url-access=limited |date=2007 |publisher=[[Springer Science & Business Media]] |isbn=9783540342588 |pages=[https://archive.org/details/historysemicondu00loje_697/page/n327 321]–3}}</ref>
In 1965, [[Chih-Tang Sah]], Otto Leistiko and A.S. Grove at [[Fairchild Semiconductor]] fabricated several NMOS devices with channel lengths between [[10 µmμm process|8{{nbsp}}µmμm]] and 65{{nbsp}}µmμm.<ref>{{cite journal |last1=Sah |first1=Chih-Tang |author1-link=Chih-Tang Sah |last2=Leistiko |first2=Otto |last3=Grove |first3=A. S. |title=Electron and hole mobilities in inversion layers on thermally oxidized silicon surfaces |journal=[[IEEE Transactions on Electron Devices]] |date=May 1965 |volume=12 |issue=5 |pages=248–254 |doi=10.1109/T-ED.1965.15489 |bibcode=1965ITED...12..248L |url=https://pdfslide.net/documents/electron-and-hole-mobilities-in-inversion-layers-on-thermally-oxidized-silicon-57e531d33262d.html}}</ref> Dale L. Critchlow and [[Robert H. Dennard]] at [[IBM]] also fabricated NMOS devices in the 1960s. The first IBM NMOS product was a [[memory chip]] with 1{{nbsp}}[[kibibit|kb]] data and 50{{ndash}}100 [[nanosecond|ns]] [[access time]], which entered large-scale manufacturing in the early 1970s. This led to MOS [[semiconductor memory]] replacing earlier [[bipolar junction transistor|bipolar]] and [[ferrite-core memory]] technologies in the 1970s.<ref>{{cite journal |last1=Critchlow |first1=D. L. |title=Recollections on MOSFET Scaling |journal=IEEE Solid-State Circuits Society Newsletter |date=2007 |volume=12 |issue=1 |pages=19–22 |doi=10.1109/N-SSC.2007.4785536 |doi-access=free }}</ref>
