SUMMARY / RELATED TOPICS

CMOS

Complementary metal–oxide–semiconductor known as complementary-symmetry metal–oxide–semiconductor, is a type of MOSFET fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFETs for logic functions. CMOS technology is used for constructing integrated circuit chips, including microprocessors, memory chips, other digital logic circuits. CMOS technology is used for analog circuits such as image sensors, data converters, RF circuits, integrated transceivers for many types of communication. Mohamed M. Atalla and Dawon Kahng invented the MOSFET at Bell Labs in 1959, demonstrated the PMOS and NMOS fabrication processes in 1960; these processes were combined and adapted into the complementary MOS process by Chih-Tang Sah and Frank Wanlass at Fairchild Semiconductor in 1963. RCA commercialized the technology with the trademark "COS-MOS" in the late 1960s, forcing other manufacturers to find another name, leading to "CMOS" becoming the standard name for the technology by the early 1970s.

CMOS overtook NMOS as the dominant MOSFET fabrication process for large-scale integration chips in the 1980s, has since remained the standard fabrication process for MOSFET semiconductor devices in VLSI chips. As of 2011, 99% of IC chips, including most digital and mixed-signal ICs, are fabricated using CMOS technology. Two important characteristics of CMOS devices are high noise immunity and low static power consumption. Since one transistor of the MOSFET pair is always off, the series combination draws significant power only momentarily during switching between on and off states. CMOS devices do not produce as much waste heat as other forms of logic, like NMOS logic or transistor–transistor logic, which have some standing current when not changing state; these characteristics allow CMOS to integrate a high density of logic functions on a chip. It was for this reason that CMOS became the most used technology to be implemented in VLSI chips; the phrase "metal–oxide–semiconductor" is a reference to the physical structure of MOS field-effect transistors, having a metal gate electrode placed on top of an oxide insulator, which in turn is on top of a semiconductor material.

Aluminium was once used but now the material is polysilicon. Other metal gates have made a comeback with the advent of high-κ dielectric materials in the CMOS process, as announced by IBM and Intel for the 45 nanometer node and smaller sizes. "CMOS" refers to both a particular style of digital circuitry design and the family of processes used to implement that circuitry on integrated circuits. CMOS circuitry dissipates less power than logic families with resistive loads. Since this advantage has increased and grown more important, CMOS processes and variants have come to dominate, thus the vast majority of modern integrated circuit manufacturing is on CMOS processes. CMOS logic consumes over 7 times less power than NMOS logic, about 100,000 times less power than bipolar transistor-transistor logic. CMOS circuits use a combination of p-type and n-type metal–oxide–semiconductor field-effect transistor to implement logic gates and other digital circuits. Although CMOS logic can be implemented with discrete devices for demonstrations, commercial CMOS products are integrated circuits composed of up to billions of transistors of both types, on a rectangular piece of silicon of between 10 and 400 mm2.

CMOS always uses all enhancement-mode MOSFETs. The MOSFET was invented by Mohamed M. Atalla and Dawon Kahng at Bell Labs in 1959. There were two types of MOSFET fabrication processes, PMOS and NMOS. Both types were developed by Atalla and Kahng when they invented the MOSFET, fabricating both PMOS and NMOS devices with a 20 μm process in 1960. While the MOSFET was overlooked and ignored by Bell Labs in favour of bipolar transistors, the MOSFET invention generated significant interest at Fairchild Semiconductor. Based on Atalla's work, Chih-Tang Sah introduced MOS technology to Fairchild with his MOS-controlled tetrode fabricated in late 1960. A new type of MOSFET logic combining both the PMOS and NMOS processes was developed, called complementary MOS, by Chih-Tang Sah and Frank Wanlass at Fairchild. In February 1963, they published the invention in a research paper. Wanlass filed US patent 3,356,858 for CMOS circuitry in June 1963, it was granted in 1967. In both the research paper and the patent, the fabrication of CMOS devices was outlined, on the basis of thermal oxidation of a silicon substrate to yield a layer of silicon dioxide located between the drain contact and the source contact.

CMOS was commercialised by RCA in the late 1960s. RCA adopted CMOS for the design of integrated circuits, developing CMOS circuits for an Air Force computer in 1965 and a 288-bit CMOS SRAM memory chip in 1968. RCA used CMOS for its 4000-series integrated circuits in 1968, starting with a 20 μm semiconductor manufacturing process before scaling to a 10 μm process over the next several years. CMOS technology was overlooked by the American semiconductor industry in favour of NMOS, more powerful at the time. However, CMOS was adopted and further advanced by Japanese semiconductor manufacturers due to its low power consumption, leading to the rise of the Japanese semiconductor industry. Toshiba developed C²MOS, a circuit technology with lower p

Kusatsu Special Prison

Kusatsu Special Prison was a prison that operated between 1938 and 1947, in Kuryu Rakusen-en Sanatorium in Kusatsu Onsen, Kusatsu town, Gunma Prefecture, where criminals in public leprosariums throughout Japan were imprisoned. Prisons for conventional crimes had been built earlier in all public leprosariums. 22 out of 93 prisoners died of cold or maltreatment after confinement. In Japanese, it was called Jyu Kanbo. In 1909, the first public leprosy policy started in Japan, creating public leprosariums which accommodated wandering lepers. In 1915, the treatment of criminals was discussed by leprosarium directors. In 1916, the leprosy prevention law was amended and this time, decisions of confinement and custody could be made by directors of leprosariums, reduction of meals and 30-day confinement in a leprosarium. Between 1912 and 1951, several riots took place in leprosariums. Kusatsu Special Prison was completed at the end of 1938. There were 8 independent cells. There was a small hole for the distribution of meals.

There was no heating system. The cells had tall walls and were physically separate from each other, each cell being a separate building entity; the temperature would reach -20 °C. Administration and repression were roles partaken by male nurses. Deaths in prison –14. On August l, Prince Takamatsu entered the prison, he asked the sanatorium staff several questions. On August 11, Japan Communist Party members, in preparation for a coming upper house election, visited the sanatorium and were surprised to see the prison. On Aug. 22, discussions between patients and the sanatorium began. When the diet problem was discussed, the director was changed and the responsible section-chief was dismissed. Jun Takada, 19 at that time, testified against the prison. Transfer of dead bodies: The season was winter, we had to obey the order of the doctors, it was about 10 in the morning. I carried about 6 bodies; the dead body was like a dried frog. It was violet in color. We covered him with futon, carried the futon and placed the body on a stretcher.

The place was dark and the door was going to close, we shouted "Don't close". The necessity of a prison was disputed in the diet and Kikuchi Medical Prison was built in 1953 in Kōshi city, Kumamoto Prefecture. Fuusetsu no Mon, 50 years of Kuryu Rakusen-en, Jichikai, 1082. A History of Leprosy in Japan. Shun-Ichi Yamamoto, Tokyo University Press, 1993. ISBN 4-13-066401-8 C3047 P8755E The Records of Hansen's Disease Prison, Michio Miyasaka, Shueicha, 2006. ISBN 4-08-720339-5 C0212 Y660E Jyu-kanbo National Museum of Detention for Hansen's Disease Patients