The growing demands on the electronic machines caused also the growth of their dimensions, weight, complexity and of course the growth of their prices, too. An eighteen-thousand-valve-computer was occupying the space of several rooms. The price of the electronic equipment in a bomber was several times higher than the price of the aeroplane itself. Together with the complexity, the failure rate and the operating-staff-demand were growing. The struggle for increasing the reliability lead to doubling the important parts of the machinery. And so they became even more cumbersome. It was obvious, the next development would need more assets and that it would be necessary to use the new, qualitatively different materials and their attributes.

According to certain pre-war experience with semiconductors, these were the ones chosen for the next development. And so in 1946 a “semiconductors´ team” was established in Bell’s telephone labs in USA. Its members were William Shockley, John Bardeen and Walter Brattain. Right away in January 1946 they made the first grand decision: they turned they attention to the crystals of Silicon and Germanium. They were completely ignoring the other materials used in previous investigations. In the end of the year1947 they were trying to modify the attributes of the exterior Germanium layer, with the electrolytes surrounding the metal contacts. Later they replaced the electrolytes with a fomented golden point, which was creating a dotted contact. In the end Brattain placed the contacts on two strips of a golden foil. These were stored close to each other and were pressed into the Germanium. When he attached it to the electric circuit he detected the increase of energy: the “transistor” effect was discovered! This happened on 16^th January 1947, nearly two and half years after the team’s foundation. On the Christmas Eve the new invention was introduced to the top management of the Bell’s labs. But the publication was put off for six months, till June 1948: first because of the understanding this invention and mainly because of the preparation of the patent “position”. But the physical fundaments of this invention were not known yet...
But the transfer resistor had already been born!

The first transistor (germanium is at the bottom of the triangel)
(the pictures above were taken over from http://www.lucent.com/ideas/heritage/transistor/history.html)

The first step to the explication of the physical fundaments of the transistor were made by Shockles´ formulation of the Theory of positive-negative conversions. Important was also the role of emitting the moving charge-carriers on one side and their receiving (collecting) on the opposite side. He brilliantly concluded his analysis with the invention of a junction transistor. According to his conceptions it was a sandwich adjustment of a small tablet made from the n-material between two p-type areas (or conversely). One month later – in February 1948 – John Shive did the experiment of principle: he put two phosphor-bronze contacts to the opposite sides of the Germanium tablet (0,1 mm thick). The behaviour of this transistor corresponded with Shockley´s theory. Then Shockley continued in another team of fellow-workers and after many experiments he finished his junction theory and so he created solid fundaments of the “transistor” phenomenon (he published this theory in 1950 in – today well known - classical text Electrons and Holes in Semiconductors).

The theory was clear, however two types of transistor designs existed at that time, but none of them was good enough for the manufacturing. The first one was the dotted transistor (this type was created as the first one). The second one is the junction transistor created by Shockley. The dotted one was could have been manufactured at that time but had had many insufficiencies. Mainly the great dispersion of the electric attributes. With some exaggeration we could say, that each piece was an original. But despite these problems this type was being manufactured for more then 10 years, e.g. like the telephone oscillators or the ear-trumpets for the hard of hearing – their production had to be quitted because of their bad quality). In the second case the question were the junction transistors. Their attributes were in the expected limits but they were more complicated to manufacture and were material-purity demanding.

As we enunciated at the beginning, two materials were used: Germanium and Silicon. Already since the beginning it was known, that Silicon has got more suitable attributes. E.g. it is energetically more advantageous, is less dependent on the temperature changes and the current in the back circuit is smaller. But at the beginning the manufacturing of Silicon with the demanded quality was aggravated with the demanding chemical and metallurgical process. E.g. the smelting temperature of Silicon is 1415 °C and of Germanium only 937 °C. The right way of Silicon manufacturing, which would assure the cleanliness comparable with Germanium was not found untill 1953.

In the meantime (1952) the Bell’s labs sold the patent-rights for transistor to everyone who was ready to pay 25.000 $ for it.

The first commercially manufactured Silicon transistors (1954)

The mass manufacturing of transistor could begin. In 1952 the thickness of the base-tablet was cut back to 10 micromilimeters and so the marginal frequency of the transistor was increased up to 10 MHz. The first diffuse Germanium mesa transistor with the marginal frequency 500 MHz was manufactured in 1954. A year later a Silicon one was produced. In 1956 the original “transistor” team gets a Nobel prize …

Jack Kilby demonstrates his first integrated circuit
(the two pictures above were taken over from http://www.ti.com/corp/docs/history/1950snf.htm)

The next development of miniaturisation in this field was quicken with the Russian success with the first satellites Earth type Sputnik. So called integrated circuit  was created. The fist success was reached by Jack Kilby at the end of August 1958. His integrated circuit  was created with miniature resistors, condensers, diodes and transistors on one Silicon tablet. The mutual interconnection was accomplished “classically” with the wires. In the next year in January Robert Noyce tried to do the same: but he created the interconnections in a photographic way and by etching the aluminium or golden foil. The fight for the author’s rights between both these inventors and their companies lasted until the half of 60´s, longer the development itself …

The first consumer goods (ear-trumpet) with a integrated circuit  (1964)
(fig. from page http://www.ti.com/corp/docs/history/1960snf.htm)