On December 23, 1947, in a private demonstration for AT&T
executives, the Bell Laboratories research team, the 1956 Nobel Prize
winners John Bardeen, Walter H. Brattain, and William Shockley,
demonstrated the point-contact transistor3) as a working amplifier.
In the demonstration, speech was amplified using the transistor.
The transistor was born!
The development was launched from a base of contributions made
by Bell Laboratories scientists and engineers, whose pioneering work on
semiconductors made a new class of semiconductors available to
physicists. The invention of the point-contact transistor was the
interim result in a research effort, which had begun during the
Spring of 1945. The objective of this effort was the junction
field-effect transistor.
The field-effect device was by no means unknown by then. The basic
principle of the field-effect transistor was proposed by
Julius Edgar Lilienfeld
4) [8] as early as
1925. In 1934, Oskar Heil [6] described a structure
similar to the junction field-effect transistor.
However, practical implementations were impossible due to
materials-related problems. The technology to produce such devices
on a commercial basis did not yet exist.
The 1945 experiments, proposed by William Shockley, on a thin-film
field-effect transistor failed. In early 1946, John Bardeen proposed
that problems of surface-state charges shielded the gate field from
the semiconductor interior, and for the next eighteen months the
`transistor research team' focussed on penetrating the shield.
In an experiment on 17 November, 1947, Walter H. Brattain overcame
the blocking effect of the surface states, and during the forthcoming
`magic month'[12], a sequence of `creative
failures' led to the invention of the point-contact transistor:
. . . Bardeen and I were simply trying to make a good `Field
Effect' device and as a result, we were put in a situation to
observe, for the first time, a phenomenon (namely minority carrier
injection [3]) now called the `Transistor Effect' -
and to use this to make a transistor![5]
An entry in W.H. Brattain's notebook shows that on 16 December, 1947,
point-contact amplification [2] was observed.
The discovery was demonstrated to AT&T executives on December 23 and
recorded in Brattain's Christmas Eve notebook entry.
The invention of the junction (bipolar) transistor, superior to
the point-contact transistor, followed shortly after, on 23 January,
1948. And eventually, on 30 June, 1948, the bipolar transistor was
announced[4].
The impact of the transistor was no less than revolutionary.
Inherent to the transistor is the availability of electrons
to meet the transistor operation needs without the use of
power e.g. to energize a hot cathode as in the vacuum triode tube.
Small size, low power consumption, low collector potentials and
finally, a dramatically improved reliability, were the immediate
benefits over electron tubes. With the maturing of technology,
the manufacturing costs should proove much less than electron tubes.
For the U.S. Military, the urgent requirements for national
security overrode the high costs of early transistors, and the
military initiated several research programs to develop transistors
and circuits for military use. The motivation was to promote the
effort to miniaturize complex electronic systems to be installed
in equipment in which size, weight, and power consumption were
severely constrained
5).
In a paper in 1952 by I.R. Obenchain [11], the
development of portable computers as well as advanced electronic
control systems for weapons was forecasted. And for three decades
to come, military initiated research should remain the primary
funding for research in integrated circuits.
Author:
Flemming Stassen
(http://www.it.dtu.dk/~stassen/Edu/49260/Historie)