The main stages of electronics development

The first stage of electronics development covered a period from 1904 (diode discovery) to 1948 (transistor discovering). Vacuum and gas-discharge devices were developed at this stage.

The structure of the first electronic tube was proposed by the English physicist D. Flemink in 1904. That tube containing two electrodes, a cathode and an anode, was called a diode. A cathode was heated until electron emission occurred. A positive potential was applied to the anode (plate). Under the influence of the positive plate potential electrons flowed from the cathode to the plate. That flow of electrons was a plate current. When anegative potential was applied to the plate, no plate current occurred. Hence, the conduction of an electro-vacuum diode depended on a plate voltage.

In 1907 the American engineer Ly-De-Forest proposed a structure of electro-vacuum triode. He added a metal grid between a cathode and a plate. A grid gave a possibility to control high power by low voltage applied to it.

Gas-discharge devices such as stabilivolt and thyratron were also created at that time. Electrons moving into a gas-filled tube ionize gas, and gas turns into conductive plasma. The first generation of electronic devices consumed a lot of energy, had low reliability and a short service life.

The second stage of electronics development started whena transistor was invented. In 1931 the English physicist Alan Wilson discovered a theory of semiconductors. He classified them into intrinsic and extrinsic (with foreign impurities), donor and acceptor semiconductors. In 1948 the American physicists John Bardeen, Walter Brattain and William Shockly proposed a new type of electronics - a bipolar transistor. For this achievement, the three scientists shared in 1956 Nobel Prize in physics. There were created FETs, solar batteries, thyristors, tunnel diodes, optrons in 50-s. MOS-transistors (metal-oxide-semiconductor) were designed in 1960. FET with a Shottky barrier was proposed in 1966.

Comparison of semiconductor devices with vacuum devices

The planer technology has been put into practice since 1958, and it has provided fast development of integrated circuitry. Active devices of the first and second generations were elements of discrete electronics. The transition from discrete elements to functional blocks happened at the third stage of electronics development. Thus, the changes which happened under the transition from the first stage to the second one were quantitative in character, whereas the transition from the second stage to the third one provided the qualitative changes.

The first IC’s included up to 10 elements in a crystal. Their length was 10 μm. By the end of 80-s these indexes were, accordingly, 10⁷ elements on 1 μm of a length. Scientists predict that in the neart future there will be 100 million transistors in one crystal.

The further development of active electronic devices is going inthree directions:

1. The first is traditional design - engineering.

2. The second is non-traditional using functional electronic

devices.

3. The third is molecule synthesis.

The first direction is leading to IC miniaturization and increasing an integration level. They predict increasing transistor density up to 1 million permm², frequency up to 13 gHz and reducing a source voltage to 0.5-0.6V.

The second direction is solving the problem of miniaturization and reliability using new physical phenomena. The distribution parameter medium is used in such systems, and a multivariable signal is a source of information there. A lot of phenomena such as opto-electronic, acousto-electronic and magneto-electronic are widely used in functional electronics.

The third direction is based on self-adjusting physical-chemical processes.