:
The transistor


The transistor and subsequently the integrated circuits must certainly qualify as two of the greatest inventions of the twentieth century. These devices are formed from materials known as semiconductors, whose properties were not well-understood until the 1950s. The name transistor is short for "transfer resistance". (Miniaturization of electronic circuits via the transistor is a key development making personal desktop computers small, reliable, and affordable.)

As far back as 1926, Dr. Julius Edgar Lilienfield from New York filed for a patent on what we would now recognize as an NPN junction transistor being used in the role of an amplifier (the patent title was "Method and apparatus for controlling electric currents")

Unfortunately, serious research on semiconductors didn't really commence until World War II. At that time it was recognized that devices formed from semiconductors had potential as amplifiers and switches, and could therefore be used to replace the prevailing technology of vacuum tubes, but that they would be much smaller, lighter, and would require less power. All of these factors were of interest to the designers of the radar systems which were to play a large role in the war.

In 1945Bell Laboratories in the United States began research into semiconductors and physicists William Shockley, Walter Brattain and John Bardeen succeeded in creating the first point- contact germanium transistor on the 23rd December, 1947
(they took a break for the Christmas holidays before publishing their achievement, which is why some reference books state that the first transistor was created in 1948).

In 1950,
Shockley invented a new device called a bipolar junction transistor, which was more reliable, easier and cheaper to build, and gave more consistent results than point-contact devices.

In May 1954 Texas Instruments announced the start of commercial production on silicon transistors. (bipolar transistors were being manufactured out of silicon rather than germanium although germanium had certain electrical advantages, silicon was cheaper and easier to work with). Bipolar junction transistors are formed from the junction of three pieces of doped silicon called the collector, base, and emitter. The original bipolar transistors were manufactured using the mesa process, in which a doped piece of silicon called the mesa (or base) was mounted on top of a larger piece of silicon forming the collector, while the emitter was created from a smaller piece of silicon embedded in the base.
The company became a household name when the first transistor radio incorporated Teal's invention. The radio, sold by Regency Electronics for $50, launched the world into a global village of instant news and pop music.

In 1955 AT&T Bell Laboratories announced the first fully transistorized computer, TRADIC. It contained nearly 800 transistors instead of vacuum tubes. Transistors -- completely cold, highly efficient amplifying devices invented at Bell Labs -- enabled the machine to operate on fewer than 100 watts, or one-twentieth the power required by comparable vacuum tube computers.
In this photograph, J. H. Felker (right) gives instructions to the TRADIC computer by means of a plug-in unit while J. R. Harris places numbers into the machine by flipping simple switches. The computer occupied only 3 cubic feet.

In 1956 The Nobel Prize in physics is awarded to John Bardeen, Walter Brattain, and William Shockley for their work on the transistor. Also in 1956 The first transistorized computer is completed, the TX-O (Transistorized Experimental computer), at the Massachusetts Institute of Technology. (while not a microcomputer, this is is a step forward in the evolution of reducing the size of conventional vacuum tube-based computers.)

In 1959, the Swiss physicist Jean Hoerni invented the planar process, in which optical lithographic techniques were used to diffuse the base into the collector and then diffuse the emitter into the base. One of Hoerni's colleagues, Robert Noyce, invented a technique for growing an insulating layer of silicon dioxide over the transistor, leaving small areas over the base and emitter exposed and diffusing thin layers of aluminum into these areas to create wires. The processes developed by Hoerni and Noyce led directly to modern integrated circuits

In 1962 IBM develops the first automatic mass-production facility for transistors, in New York.

In 1962, Steven Hofstein and Fredric Heiman at the RCA research laboratory in Princeton, New Jersey, invented a new family of devices called metal-oxide semiconductor field-effect transistors (MOS FETs for short). Although these transistors were somewhat slower than bipolar transistors, they were cheaper, smaller and used less power. Also of interest was the fact that modified metal-oxide semiconductor structures could be made to act as capacitors or resistors.

In 1965 Gordon Moore, head of research and development for Fairchild Semiconductor, predicts that transistor density on integrated circuits would double every 12 months for the next ten years. This prediction is revised in 1975 to doubling every 18 months, and becomes known as Moore's Law.

June 4 1964 The US Patent & Trademark Office grants patent 3,387,286 to Dr. Robert Dennard, of the IBM T.J. Watson Research Center. The patent is for a one-transistor DRAM cell and the basic idea in the three-transistor cell. (Dynamic RAM (Random Access Memory) will become the standard short-term storage medium for programs and data during processing.

top>>