Editing Semiconductor memory (section)

==History==
{{See also|Computer memory|Memory cell (computing)}}

Early [[computer memory]] consisted of [[magnetic-core memory]], as early [[solid-state electronic]] [[semiconductors]], including [[transistors]] such as the [[bipolar junction transistor]] (BJT), were impractical for use as digital storage elements ([[Memory cell (computing)|memory cells]]). The earliest semiconductor memory dates back to the early 1960s, with bipolar memory, which used bipolar transistors.<ref name="computerhistory1966">{{cite web |title=1966: Semiconductor RAMs Serve High-speed Storage Needs |url=https://www.computerhistory.org/siliconengine/semiconductor-rams-serve-high-speed-storage-needs/ |website=[[Computer History Museum]] |access-date=19 June 2019}}</ref> '''Bipolar semiconductor memory '''made from [[discrete device]]s was first shipped by [[Texas Instruments]] to the [[United States Air Force]] in 1961. The same year, the concept of [[Solid-state electronics|solid-state]] memory on an [[integrated circuit]] (IC) chip was proposed by [[applications engineers|applications engineer]] Bob Norman at [[Fairchild Semiconductor]].<ref name="computerhistory-timeline">{{cite web |title=Semiconductor Memory Timeline Notes |url=http://corphist.computerhistory.org/corphist/documents/doc-4803f82fa3ba8.pdf |website=[[Computer History Museum]] |date=November 8, 2006 |access-date=2 August 2019}}</ref> The '''first single-chip''' memory IC was the BJT 16-bit IBM SP95 fabricated in December 1965, engineered by Paul Castrucci.<ref name="computerhistory1966"/><ref name="computerhistory-timeline"/> While bipolar memory offered improved performance over magnetic-core memory, it could not compete with the lower price of magnetic-core memory, which remained dominant up until the late 1960s.<ref name="computerhistory1966"/> Bipolar memory failed to replace magnetic-core memory because bipolar [[Flip-flop (electronics)|flip-flop]] circuits were too large and expensive.<ref>{{cite book |last1=Orton |first1=John W. |title=Semiconductors and the Information Revolution: Magic Crystals that made IT Happen |date=2009 |publisher=[[Academic Press]] |isbn=978-0-08-096390-7 |page=104 |url=https://books.google.com/books?id=6YLL9197NfMC&pg=PA104}}</ref>

=== MOS memory ===
{{See also|MOSFET}}

The advent of the [[metal–oxide–semiconductor field-effect transistor]] (MOSFET),<ref name="sciencedirect">{{cite web |title=Transistors – an overview |url=https://www.sciencedirect.com/topics/computer-science/transistors |website=[[ScienceDirect]] |access-date=8 August 2019}}</ref> invented by [[Mohamed M. Atalla]] and [[Dawon Kahng]] at [[Bell Labs]] in 1959,<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> enabled the practical use of [[metal–oxide–semiconductor]] (MOS) transistors as [[memory cell (computing)|memory cell]] storage elements, a function previously served by [[magnetic-core memory|magnetic cores]] in [[computer memory]].<ref name="sciencedirect"/> MOS memory was developed by John Schmidt at [[Fairchild Semiconductor]] in 1964.<ref name="computerhistory1970"/><ref>{{Cite book |url=https://books.google.com/books?id=kG4rAQAAIAAJ&q=John+Schmidt |title=Solid State Design. Vol. 6 |date=1965 |publisher=Horizon House}}</ref> In addition to higher performance, MOS memory was cheaper and consumed less power than magnetic-core memory.<ref name="computerhistory1970">{{cite web |title=1970: MOS Dynamic RAM Competes with Magnetic Core Memory on Price |url=https://www.computerhistory.org/siliconengine/mos-dynamic-ram-competes-with-magnetic-core-memory-on-price/ |website=[[Computer History Museum]] |access-date=29 July 2019}}</ref> This led to MOSFETs eventually replacing magnetic cores as the standard storage elements in computer memory.<ref name="sciencedirect"/>

In 1965, J. Wood and R. Ball of the [[Royal Radar Establishment]] proposed digital storage systems that use [[CMOS]] (complementary MOS) memory cells, in addition to MOSFET [[power devices]] for the [[power supply]], switched cross-coupling, [[switches]] and [[delay-line memory|delay-line storage]].<ref>{{cite conference |last1=Wood |first1=J. |last2=Ball |first2=R. |title=The use of insulated-gate field-effect transistors in digital storage systems |conference=1965 IEEE International Solid-State Circuits Conference. Digest of Technical Papers |date=February 1965 |volume=VIII |pages=82–83 |doi=10.1109/ISSCC.1965.1157606}}</ref> The development of [[silicon-gate]] [[MOS integrated circuit]] (MOS IC) technology by [[Federico Faggin]] at Fairchild in 1968 enabled the production of MOS [[memory chip]]s.<ref>{{cite web |title=1968: Silicon Gate Technology Developed for ICs |url=https://www.computerhistory.org/siliconengine/silicon-gate-technology-developed-for-ics/ |website=[[Computer History Museum]] |access-date=10 August 2019}}</ref> [[NMOS logic|NMOS]] memory was commercialized by [[IBM]] in the early 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> MOS memory overtook magnetic core memory as the dominant memory technology in the early 1970s.<ref name="computerhistory1970"/>

The term "memory" when used with reference to computers most often refers to volatile [[random-access memory]] (RAM). The two main types of volatile RAM are [[static random-access memory]] (SRAM) and [[dynamic random-access memory]] (DRAM). Bipolar SRAM was invented by Robert Norman at Fairchild Semiconductor in 1963,<ref name="computerhistory1966"/> followed by the development of MOS SRAM by John Schmidt at Fairchild in 1964.<ref name="computerhistory1970"/> SRAM became an alternative to magnetic-core memory, but required six MOS transistors for each [[bit]] of data.<ref name="ibm100">{{cite web |title=DRAM |url=https://www.ibm.com/ibm/history/ibm100/us/en/icons/dram/ |website=IBM100 |publisher=[[IBM]] |access-date=20 September 2019 |date=9 August 2017}}</ref> Commercial use of SRAM began in 1965, when IBM introduced their SP95 SRAM chip for the [[IBM System/360|System/360 Model 95]].<ref name="computerhistory1966"/>

[[Toshiba]] introduced bipolar DRAM [[Memory cell (computing)|memory cells]] for its Toscal BC-1411 [[electronic calculator]] in 1965.<ref name="bc-spec">{{cite web|url=http://www.oldcalculatormuseum.com/s-toshbc1411.html|title=Spec Sheet for Toshiba "TOSCAL" BC-1411|website=Old Calculator Web Museum|access-date=8 May 2018|url-status=live|archive-url=https://web.archive.org/web/20170703071307/http://www.oldcalculatormuseum.com/s-toshbc1411.html|archive-date=3 July 2017}}</ref><ref name="bc">[http://www.oldcalculatormuseum.com/toshbc1411.html Toshiba "Toscal" BC-1411 Desktop Calculator] {{webarchive|url=https://web.archive.org/web/20070520202433/http://www.oldcalculatormuseum.com/toshbc1411.html |date=2007-05-20 }}</ref> While it offered improved performance over magnetic-core memory, bipolar DRAM could not compete with the lower price of the then dominant magnetic-core memory.<ref>{{cite web |title=1966: Semiconductor RAMs Serve High-speed Storage Needs |url=https://www.computerhistory.org/siliconengine/semiconductor-rams-serve-high-speed-storage-needs/ |website=Computer History Museum}}</ref> MOS technology is the basis for modern DRAM. In 1966, Dr. [[Robert H. Dennard]] at the [[IBM Thomas J. Watson Research Center]] was working on MOS memory. While examining the characteristics of MOS technology, he found it was capable of building [[capacitors]], and that storing a charge or no charge on the MOS capacitor could represent the 1 and 0 of a bit, while the MOS transistor could control writing the charge to the capacitor. This led to his development of a single-transistor DRAM memory cell.<ref name="ibm100"/> In 1967, Dennard filed a patent under IBM for a single-transistor DRAM memory cell, based on MOS technology.<ref>{{cite web |title=Robert Dennard |url=https://www.britannica.com/biography/Robert-Dennard |website=[[Encyclopedia Britannica]] |access-date=8 July 2019}}</ref> This led to the first commercial DRAM IC chip, the [[Intel 1103]], in October 1970.<ref name="Intel2003">{{cite web |title=Intel: 35 Years of Innovation (1968–2003) |url=https://www.intel.com/Assets/PDF/General/35yrs.pdf |publisher=Intel |year=2003 |access-date=26 June 2019 |archive-url=https://web.archive.org/web/20211104070452/https://www.intel.com/Assets/PDF/General/35yrs.pdf |archive-date=4 November 2021 |url-status=dead}}</ref><ref name="HC">[http://history-computer.com/ModernComputer/Basis/dram.html ''The DRAM memory of Robert Dennard'']. history-computer.com.</ref><ref name="Lojek-1103">{{cite book |last1=Lojek |first1=Bo |title=History of Semiconductor Engineering |date=2007 |publisher=[[Springer Science & Business Media]] |isbn=9783540342588 |pages=362–363 |url=https://books.google.com/books?id=2cu1Oh_COv8C&pg=PA362 |quote=The i1103 was manufactured on a 6-mask silicon-gate P-MOS process with 8 μm minimum features. The resulting product had a 2,400&nbsp;µm, 2 memory cell size, a die size just under 10&nbsp;mm<sup>2</sup>, and sold for around $21.}}</ref> [[Synchronous dynamic random-access memory]] (SDRAM) later debuted with the [[Samsung Electronics|Samsung]] KM48SL2000 chip in 1992.<ref>{{cite web |title=KM48SL2000-7 Datasheet |url=https://www.datasheetarchive.com/KM48SL2000-7-datasheet.html |publisher=[[Samsung]] |access-date=19 June 2019 |date=August 1992}}</ref><ref name="electronic-design">{{cite journal |title=Electronic Design |journal=[[Electronic Design]] |date=1993 |volume=41 |issue=15–21 |url=https://books.google.com/books?id=QmpJAQAAIAAJ |publisher=Hayden Publishing Company |quote=The first commercial synchronous DRAM, the Samsung 16-Mbit KM48SL2000, employs a single-bank architecture that lets system designers easily transition from asynchronous to synchronous systems.}}</ref>

The term "memory" is also often used to refer to [[non-volatile memory]], specifically [[flash memory]]. It has origins in [[read-only memory]] (ROM). [[Programmable read-only memory]] (PROM) was invented by [[Wen Tsing Chow]] in 1956, while working for the Arma Division of the American Bosch Arma Corporation.<ref name="Huang2008">{{cite book |author=Han-Way Huang |title=Embedded System Design with C805 |url=https://books.google.com/books?id=3zRtCgAAQBAJ&pg=PA22 |date=5 December 2008 |publisher=Cengage Learning |isbn=978-1-111-81079-5 |page=22 |url-status=live |archive-url=https://web.archive.org/web/20180427092847/https://books.google.com/books?id=3zRtCgAAQBAJ&pg=PA22 |archive-date=27 April 2018}}</ref><ref name="AufaureZimányi2013">{{cite book |author1=Marie-Aude Aufaure |author2=Esteban Zimányi |title=Business Intelligence: Second European Summer School, eBISS 2012, Brussels, Belgium, July 15–21, 2012, Tutorial Lectures |url=https://books.google.com/books?id=7iK5BQAAQBAJ&pg=PA136 |date=17 January 2013 |publisher=Springer |isbn=978-3-642-36318-4 |page=136 |url-status=live |archive-url=https://web.archive.org/web/20180427092847/https://books.google.com/books?id=7iK5BQAAQBAJ&pg=PA136 |archive-date=27 April 2018}}</ref> In 1967, Dawon Kahng and [[Simon Sze]] of Bell Labs proposed that the [[Floating gate MOSFET|floating gate]] of a MOS [[semiconductor device]] could be used for the cell of a reprogrammable [[read-only memory]] (ROM), which led to [[Dov Frohman]] of [[Intel]] inventing [[EPROM]] (erasable PROM) in 1971.<ref name="computerhistory1971">{{cite web |title=1971: Reusable semiconductor ROM introduced |url=https://www.computerhistory.org/storageengine/reusable-semiconductor-rom-introduced/ |website=[[Computer History Museum]] |access-date=19 June 2019}}</ref> [[EEPROM]] (electrically erasable PROM) was developed by Yasuo Tarui, Yutaka Hayashi and Kiyoko Naga at Japan's [[Ministry of International Trade and Industry]] (MITI) [[Electrotechnical Laboratory]] in 1972.<ref>{{cite journal |last1=Tarui |first1=Y. |last2=Hayashi |first2=Y. |last3=Nagai |first3=K. |title=Electrically reprogrammable nonvolatile semiconductor memory |journal=IEEE Journal of Solid-State Circuits |date=1972 |volume=7 |issue=5 |pages=369–375 |doi=10.1109/JSSC.1972.1052895 |issn=0018-9200 |bibcode=1972IJSSC...7..369T}}</ref> Flash memory was invented by [[Fujio Masuoka]] at [[Toshiba]] in the early 1980s.<ref>{{cite web |last=Fulford |first=Benjamin |title=Unsung hero |work=Forbes |date=24 June 2002 |access-date=18 March 2008 |url=https://www.forbes.com/global/2002/0624/030.html |url-status=live |archive-url=https://web.archive.org/web/20080303205125/http://www.forbes.com/global/2002/0624/030.html |archive-date=3 March 2008 |df=dmy-all }}</ref><ref>{{patent|US|4531203|Fujio Masuoka}}.</ref> Masuoka and colleagues presented the invention of [[NOR flash]] in 1984,<ref>{{cite web |title=Toshiba: Inventor of Flash Memory |url=http://www.flash25.toshiba.com |website=[[Toshiba]] |access-date=20 June 2019}}</ref> and then [[NAND flash]] in 1987.<ref>{{cite conference |title=New ultra high density EPROM and flash EEPROM with NAND structure cell |last1=Masuoka |first1=F. |last2=Momodomi |first2=M. |last3=Iwata |first3=Y. |last4=Shirota |first4=R. |year=1987 |conference=[[International Electron Devices Meeting|IEDM]] 1987 |book-title=Electron Devices Meeting, 1987 International |publisher=[[IEEE]] |df=dmy |doi=10.1109/IEDM.1987.191485}}</ref> Toshiba commercialized NAND flash memory in 1987.<ref name=":0">{{cite web |title=1987: Toshiba Launches NAND Flash |url=https://www.eweek.com/storage/1987-toshiba-launches-nand-flash |website=[[eWeek]] |date=April 11, 2012 |access-date=20 June 2019}}</ref><ref>{{cite web |title=1971: Reusable semiconductor ROM introduced |url=https://www.computerhistory.org/storageengine/reusable-semiconductor-rom-introduced/ |website=[[Computer History Museum]] |access-date=19 June 2019}}</ref>