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Appendix I
Table I.1. Road Map of development of Solid State technology.
[“A brief history of semiconductors” by Tudor Jenkins, Physics Education, 40(5),pp.430-439;
“ The lost history of the Transistor- How 50 years ago, Texas Instruments and Bell Labs pushed electronics into the Silicon Age” by Michael Riordan, IEEE Spectrum, May 2004, pp.44-49]
| Year | Invention |
| 1731-1782 | Gray(1731), Desa Guller (1742) and Volta (1782) investigate conduction in solids. |
| ? | Humphrey Davey establishes the positive Temperature Coefficient of Resistance (t.c.r)of Metals. |
| 1833 | Michael Faraday detects the negative t.c.r. of AgS( Silver Sulphide). He also observes Thermal Runaway, contact potential at the interface of dissimilar materials and surface states. |
| 1839 | Alexandre- Edmond Becquerel observes Photo-Voltaic effect in electrolysis bath containing aqueous HNO 3 as electrolyte and AgCl coated Platinum electrodes.He also observed PV effect at matal-semiconductor junction in this case Ag/AgCl interface. |
| 1873 | Witloughby Smith detected Light Dependent Resistance effect in Selenium while working on Submarine Cables but he identified it as metal. It was established as semiconductor in1907. |
| 1876 | William Grylls Adams and Richard Evans Day discovered PV effect in Selenium. |
| 1883 | PV Cell was invented by Charles Fritts. Selenium was deposited on metal substrate and Gold leaf film used as the second electrode. Cross-sectional area was 30cm 2 and thickness was only 30µm. It was working on only 1% efficiency. This device caused rectification also. |
| 1874 | Carl Ferdinand Braunn made a Point Contact Diode by pressing a wire point on galena(PbS). This was popularly known as Cat’s Whisker. This showed rectification. Similar rectification was observed in untarnished and tarnished Copper. |
| 1887 | Hertz had generated Radio Waves and it was detected by coherer. Soon Cat’s Whisker replaced the coherer. |
| 1901 | J.C. Bose got a patent for the point contact diode. |
| 1906 | Greenleaf Whitteir Pickard (an employee of AT&T) filed a patent for Si Crystal Detector for Radio Waves. The mechanism was not clear. It was hypothesized as thermoelectric effect or as electrolytic effect or as gas discharge. |
| 1915 | Carl Benedicks proposed Ge-Pt and Ge-Cu as point contact diode to be used as peak diode detector in Radios. But by then Vacuum Diode had been commercialized and it took the role of detection. |
| 1920 | CuO+Se was developed as PVC used in battery chargers, exposure meters in photography. It was also used as modulators and non-linear circuit elements. |
| 1930 | Alan F. Wilson published his seminal paper titled “Quantum Theory meets Semiconductors”. Band Theory of Solids, thermal generation of electron-hole pairs, bi-polar conduction, doping and doped semiconductors- all these phenomenon were theoretically understood. The requirement of pure semiconductor was urgently felt in order to fabricate stable, reproducible and reliable devices. |
| 1940 | Point Contact Diodes were used in RADARS at 300MHz&3GHz. |
| 1942 | By melting, cooling and recrystallization and slicing the relevant portions 99.999% pure Electronic Grade pure Polycrystalline Silicon was obtained. This exhibited rectification as well as PV effect. |
| 1942 | Karl-Lark Horowitz at Purdue University stared work on PbS and then moved to the study&production of high purity Ge. Pure Ge gave high quality Cat’s Whisker. |
| 1946 | Shockley, Bardeen&Braittain started workin on Si&Ge and on the equivalent of Triodes and Pentodes(tubes are short lived and high power consuming) at BELL Labs. |
| 16 th Dec 1947 | Point Contact Ge Transistors were invented and power gain was observed. |
| 24 th Dec. 1947 | Positive feed back was applied and sustained oscillations were observed. This was the litmus test for power gain. |
| 30 th June1948 | The invention of Point Contact Ge transistors was publicly announced. |
| Point Contact Transistor was difficult to make, difficult to control and unstable. So Bipolar Junction Transistor was proposed with N Type thin layer sandwitched between P type layers. Initially poly-crystal Ge was used to make BJT. These were irreproducible, unpredictable and low quality because of scattering from grain boundaries. Hence switch was made to single crystal Ge. | |
| 1948 | Gordon Teal&John Little grew Single Crystal Ge using Jan Czochralski Method developed in 1918. |
| April 1950 | At Bell Labs, Gordon Teal and fellow Chemist Morgan Sparks successfully made single crystal Ge BJT. |
| Feb 1951 | Ge BJT has plus points such as less reactive, lower melting point and higher mobility hence higher frequency response. But it has serious negative points. These have higher leakage currents (due to low band gap energy of 0.67eV) which are very temperature sensitive almost doubling for every 10ºCelsius rise in temperature hence device becomes useless above 75ºC. Therefore Ge BJT could never be the device of choice for armed services which needed stable, reliable equipment that performed under extreme conditions. Hence switch was made to Silicon which could operate over much larger temperature range. Teal and Buehler grew pure single crystal Si and fabricated Si Junction Diode.Calvin Fuller was developing the diffusion techniques also at BELL Labs. |
| 1952 | John E Sabey at GEC fabricated Alloy Ge Transistor. This went for mass production. |
| Early 1954 | Calvin Fuller&Gerald Pearson formed PN Junction diode by diffusion. |
| 25 th April 1954 | BELL Labs announced the successful fabrication of large area Junction Diode which could act as Solar Cell with 10% efficiency |
| 10 May 1954 | At Institute of Radio Engineers National Conference on Airborne Electronics, Dayton, Ohio, Gordon Teal then at Texas Instrument announced the fabrication and performance of diffused Si BJT. |
| January 1954 | Morris Tanenbaum at BELL Labs had also achieved a Si BJT by rate growing technique but they did not announce it. |
| The decade of 50s | TI had Si BJT market to itself for rest of the decade and thus the stage was set for the emergence of TI as the International giant in field of device manufacturing. |
| July 1954 | Charles Lee made a diffused Ge BJT with few µm thin Base operating with f T = 500MHz.Diffusion was controllable and could yield narrow bases. |
| 17March 1955 | Morris Tanenbaum fabricated a diffused Si BJT with few µm thin Base operating with f T = 120MHz. |
| Rest is history. We will see the birth and evolution of Integrated Circuits in the road map of Electronics. |
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