Shulou(Shulou.com)11/24 Report--

Happy New year, everyone. I'm Mr. Jujube.

In the first original article after the Spring Festival, I will fill in a hole and finish the sequel to "what is an Electron Tube (vacuum Tube)" (link) a year ago, that is, today's article, "what is a Transistor?"

In the last article, I mentioned that although the electronic tube can be detected and amplified, it has many shortcomings, such as large size, high failure rate, easy to damage (glass tube), high heating, high energy consumption and so on.

Because of these shortcomings, experts have been thinking about whether there are components with better performance and fewer shortcomings that can replace electronic tubes and support the long-term development of the electronics industry.

Thinking about it, they set their eyes on the ore geophone.

█ ore geophone-the world's earliest semiconductor device, ore geophone has a longer history than electron tubes. It makes use of the unidirectional current conduction characteristics of some natural ores (metal sulfides) (see above for details).

In fact, this feature is not new. This feature has been discovered many, many years ago.

In 1782, the famous Italian physicist Alessandro Volt (Alessandro Volta), after the summary of experiments, found that solid matter can be roughly divided into three types:

The first, metals such as gold, silver, copper and iron, conduct electricity easily and are called conductors.

Second, materials such as wood, glass, ceramics, mica, etc., are not easy to conduct electricity and are called insulators.

The third, between the conductor and the insulator, will discharge slowly.

Because of the bizarre properties of the third material, Volt named it "Semiconducting Nature", that is, "semiconductor properties". This is the first time in human history that the term "semiconductor" appears.

Alessandro Volt later, a number of scientists, intentionally or inadvertently, discovered some semiconductor properties. For example:

In 1833, Michael Michael Faraday discovered that the resistance of silver sulphide decreases as the temperature increases (the thermosensitive properties of semiconductors).

In 1839, French scientist Alexander Becquerel (Alexandre Edmond Becquerel) discovered that light can cause a potential difference between the two ends of some materials (the photovoltaic effect of semiconductors).

In 1873, Willoughby Smith found that the conductivity of selenium materials increased under the irradiation of light (the photoconductive effect of semiconductors).

……

At that time, no one could explain these phenomena, nor did they attract much attention.

In 1874, the German scientist Karl Braun (Karl Ferdinand Braun) discovered the above-mentioned unidirectional current conduction characteristics of natural ores (metal sulfides). This is a huge milestone.

Unfortunately, Carl Braun ignored the discovery and turned to cathode ray tubes (CRT, the foundation of modern display technology).

Later, Heinrich Hertz (Heinrich Rudolf Hertz) successfully confirmed the existence of radio electromagnetic waves, and Braun returned to radio research. He worked with Marconi to greatly improve the early wireless communication system. The two men shared the Nobel Prize in Physics in 1909.

In 1906, American engineer Greenleaf Whitler Picard (Greenleaf Whittier Pickard), based on brass ore crystals, invented the famous ore geophone (crystal detector), also known as the "cat beard geophone" (the geophone has a probe on it, much like a cat's beard, hence its name).

Ore geophone is the earliest semiconductor device of human beings. Its appearance is a "flash of light" of semiconductor materials. Although it has some defects (poor quality control, unstable work, because the ore purity is not high), it has strongly promoted the development of radio communication. Radio products based on ore geophones are widely used, which greatly strengthens the transmission of human information.

People use ore geophones, but they always don't understand how they work. In the more than 30 years since then, people have repeatedly wondered why there are semiconductors. Why can semiconductors conduct electricity in one direction?

In the early days, many people even wondered whether semiconductor materials really existed. Famous physicist Pauli once said: "people should not study semiconductors, it is a dirty mess, who knows if there are semiconductors."

█ Quantum Mechanics-the theoretical cornerstone of semiconductors in 1904, the world's first electronic tube (vacuum tube) was born, marking the beginning of the era of electronic tubes. The rise of electronic tubes has reduced people's enthusiasm for ore geophones and semiconductor technology.

Later, with the birth and development of quantum mechanics, the theoretical research of semiconductors finally made a breakthrough.

In 1928, Max Planck (Max Karl Ernst Ludwig Planck), a German physicist and one of the founders of quantum mechanics, put forward the solid energy band theory for the first time in the application of quantum mechanics to the study of metal conductivity.

Planck, the father of quantum theory, believes that under the action of external electric field, semiconductor conduction can be divided into "hole" participating conduction (i.e. P-type conduction) and electron-participating conduction (i.e. N-type conduction). Many of the strange properties of semiconductors are determined by holes and electrons. (limited to space, detailed technical principles will be introduced later. )

The emergence of band theory explains for the first time why solids can be divided into insulators, conductors and semiconductors.

In 1931, British physicist Charles Wilson (Charles Thomson Rees Wilson) put forward the physical model of semiconductors on the basis of energy band theory, which laid the theoretical foundation of semiconductors.

In 1939, the Soviet physicist. Davydov, Neville Mott, a British physicist, and Walter Hermann Schottky, a German physicist, all contributed to the basic theory of semiconductors. Davydov first recognized the role of minority carriers in semiconductors, while Schottky and Mott put forward the famous "diffusion theory".

Based on the contributions of these leaders, the basic theory building of semiconductors has been gradually laid.

█ Bell Labs-the place where miracles work to promote the development and application of semiconductors, the theory is not enough, the process should also keep up.

After the birth of the ore geophone, scientists found that the performance of this geophone has a great relationship with the purity of the ore. The higher the purity of the ore, the better the performance of the geophone.

Therefore, many scientists have studied the purification of ore materials (such as lead sulfide, copper sulfide, copper oxide, etc.), and the purification process has been continuously improved.

Here, I would like to mention the greatest laboratory in human history-Bell Labs.

In the previous article, I introduced that in order to build a long-distance telephone network, AT&T Company of the United States acquired de Forrest's transistor patent.

Later, recognizing the value of basic research such as tubes, AT&T acquired the research department of Western Electric (Western Electric) in 1925 and established Bell Laboratories on this basis.

In the 1930s, Russell Shoemaker Ohl, a scientist at Bell Labs, proposed that geophones made of purified crystal materials would completely replace electronic diodes. You know, electronic tubes were absolutely dominant in the market at that time. )

Russell Orr, the father of modern solar cells, has tested more than 100 materials one by one, and he believes that silicon crystals are the ideal material for making geophones. To test his conclusion, he extracted a high-purity silicon crystal fusion with the help of his colleague Jack Skaff.

Because Bell Labs did not have the ability to cut silicon crystals, Orr sent the fusion to a jewelry store and cut it into crystal samples of different sizes. Unexpectedly, one of the samples showed positive electrode (positive) at one end and negative electrode (negative) at the other end after illumination. Orr named them P region and N region respectively. In this way, Orr invented the world's first semiconductor PN junction.

Orr's discovery shocked Mervin J. Kelly, the director of Bell Labs.

Mervyn Kelly is an important figure in the history of semiconductor development. In 1917, he joined AT&T and worked on electronic tubes. At the end of 1930s, the research of electronic tube gradually entered the bottleneck. Mervyn Kelly found that semiconductor crystal materials are the direction of future development.

It's not just Orr that affects Mervyn Kelly.

In September 1939, World War II broke out. In order to cooperate against Germany, Britain has comprehensively strengthened its technical cooperation with the United States. Among them, an important cooperative project brought about by Britain is the radar technology invented by them in 1935.

The early British radar network, which played a great role in radar technology, is actually an extension of radio technology. The performance of radar is closely related to electronic devices. At that time, electronic tubes were the mainstream of the industry, but their signal-to-noise ratio was poor, their work was unstable, and they were easily broken, so they were rejected by the military.

During World War II, Western Electric, a subsidiary of AT&T, made a number of silicon diodes based on purified semiconductor crystals. These diodes are small in size and low in failure rate, which greatly improves the performance and reliability of the allied radar system.

Orr's invention of PN junctions, as well as the excellent performance of silicon diodes, strengthened Mervyn Kelly's determination to develop transistor technology. He secretly decided to lead Bell Labs, all in Semiconductor.

In July 1945, World War II was nearing the end. In order to adapt to the adjustment of post-war research direction, Bell Labs reorganized various research departments.

At the time, Mervyn Kelly was already executive vice president of Bell Labs. Under his impetus, Bell Labs set up three research groups. One of them is the solid State Physics Research Group.

According to Mervyn Kelly's vision, the purpose of the solid State Physics Research Group is to "find physical and chemical methods to control the arrangement and behavior of the atoms and electrons that make up the solid" under the guidance of the theory of solid physics. To produce new and useful properties.

To put it bluntly, it is actually the development of a crystal transistor.

The interior of the solid State Physics Research Group is divided into semiconductor and metallurgical groups. The head of the semiconductor group is William Shockley (William Shockley), a PhD from the Massachusetts Institute of Technology.

William Shockley is a legendary man. He was born on February 13, 1910 in London, England, and was later admitted to the Massachusetts Institute of Technology to study quantum physics.

After receiving his doctorate in 1936, Shockley was specially invited by Mervyn Kelly to join Bell Laboratories to study solid-state physics. In 1939, according to Mott-Schottky's rectification theory, combined with his own experimental results, Shockley put forward a very important "field effect" theory.

In 1942, Shockley briefly left Bell Labs to join the military Research Institute, working on depth bombs and radar bomb sights.

In particular, at the end of World War II, Shockley was invited by the US government to make a casualty assessment report on the attack on the Japanese mainland. This report not only greatly affected the later US strategy toward Japan, but also indirectly affected the US decision to drop the atomic bomb.

After World War II, in order to recognize Shockley's contribution, the US government awarded him the "National Medal of Meritorious Service", the highest medal of honor that American civilians can receive. Later, with honor, Shockley returned to Bell Labs.

In addition to Shockley, Bell Labs' solid-state physics research group also has a number of bulls, such as semiconductor expert G.L.Pearson, physical chemist R.B.Gibney, electronic circuit expert H.R.Moore, theoretical physicist J.Bardeen, experimental physicist Walter H. Brattain.

By the way, this Walter Bratton, born in Xiamen, China in 1902 (both American parents), returned to the United States in 1903.

Walter Bratton, semiconductor experts Russell Orr (the one mentioned above) and Gordon Kidd Teal, who have been working on the purification of silicon and germanium crystals, also supported the work of the solid-state physics research group.

The early work of the research group did not go well. In the year after its establishment, they carried out a large number of experiments based on Shockley's theory, but achieved little results.

In 1946, based on Shockley's field effect theory, John Bardeen put forward the "surface state" theory, which solved the problem that has plagued everyone for a long time.

John Bardeen later, John Bardeen and Walter Bratton groped their way (the process was extremely bumpy and tortuous). Finally, on December 23, 1947, they made the world's first semiconductor transistor amplifier. This is the following thing that looks very strange and crude:

The world's first transistor (based on germanium semiconductors) in the experimental notes, Bratton restrained his excitement and wrote meticulously: "Voltage gain 100, power gain 40, current loss 1max 2.5."

Pearson, Moore, Shockley and others watched their experiments at the scene and signed Bratton's notes to show their approval and proof.

At the time of naming, Bardeen and Bratton believe that the device can amplify the signal because of its resistance transformation characteristics, that is, from "low resistance input" to "high resistance output". So they named it trans-resistor (conversion resistor). Later, it was abbreviated to transistor. Qian Xuesen, a famous scientist in China, translated it into Chinese as transistor.

Let me sum up that the semiconductor property is a special conductive ability (subject to external factors). Materials with semiconductor properties are called semiconductor materials. Silicon and germanium are typical and important semiconductor materials.

Microscopically, substances arranged neatly according to certain rules are called crystals. Silicon crystal has single crystal, polycrystal, amorphous crystal and other forms.

The crystal morphology determines the energy band structure, and the energy band structure determines the electrical properties. Therefore, as a semiconductor material, silicon (germanium) crystal has such great application value.

Diodes, transistors and transistors are named functionally. Electron tubes (vacuum tubes), transistors (silicon transistors, germanium transistors) are named in principle.

Later, based on transistors, circuits are getting smaller and smaller, and integrated on semiconductor materials such as silicon (without wires), they are called integrated circuits. Integrated circuits are getting smaller and smaller, and the scale of circuits is getting larger and larger (large-scale integrated circuits), which has become a well-known chip.

Semiconductor materials are the pillars of the modern electronics industry. █ Shockley's counterattack Bardeen and Bratton invented the transistor, and there was a mixed feeling in one person's heart. This man is Shockley.

Shockley is the leader of the group and an important founder of the theory. However, he was basically not involved in the critical stages of Bardeen and Bratton's later research. In fact, he once thought that Bardeen and Bratton could not have succeeded without his own help.

After being slapped in the face, Shockley was caught in an awkward situation-he thought he was one of the inventors of the transistor and should have the right to sign the patent. The vast majority of other people think that Shockley is not directly related to the invention and should not be signed. Even, when applying for a patent later, the team made a special request to the lawyer: "be sure to exclude Shockley."

Why is it so unpleasant? Here, Xiao Zao Jun must explain the peculiar character of Shockley.

Shockley is a scientific genius. In the field of technology, he has unquestionable knowledge and ability. However, he has great deficiencies in dealing with people and team management. In today's words, "IQ is very high, EQ is very low".

He is arrogant and eccentric, and he is very mean to his colleagues and subordinates. Therefore, many people are afraid to avoid him. Very few people can maintain a good relationship with him.

With such a poor interpersonal relationship and not really involved in any team work, Shockley's patent signature appeal is naturally not supported by everyone. Even senior executives at Bell Labs warned Shockley, dealing a heavy blow to him.

In his anger, Shockley decided: "since you don't take me to play, I'll play by myself."

The transistor invented by Bardeen and Bratton should actually be called a point contact transistor. As can be seen from the picture below, this design is too crude. Although it achieves the amplification function, it has a fragile structure, is sensitive to external vibration, is not easy to manufacture, and does not have the ability of commercial application.

Shockley saw this defect and began to work on a new transistor design. On January 23, 1948, after more than a month of efforts, Shockley proposed a new transistor model with a three-layer structure, which is called junction transistor (Junction Transistor). On June 26 of that year, Shockley was granted a patent with only his own name (Patent number: US2569347A).

Shockley's patent was widely questioned at first, and many people thought the model could not be realized. Later, in 1950, Shockley's colleague and good friend Morgan Scarpas (Morgan Sparks) teamed up with Gordon Thiel to make a physical NPN transistor using the Czochralski method after a series of attempts.

In November of this year, Shockley published a book on the principle of semiconductor devices, electrons and holes in semiconductors, which theoretically elaborated the principle of junction transistors.

At the beginning of 1951, the index of junction transistors completely exceeded that of point contact transistors. Shockley's contribution to the invention of the transistor has finally been unanimously recognized by Bell Laboratories (at least at the technical level).

The outbreak of █ semiconductor industry and the birth of research team breakup transistors are of great significance to the development of human science and technology. It has the ability of the electron tube, but overcomes the shortcomings of the electron tube. From the moment it was born, it was decided that it would fully replace the electron tube.

In the 1950s, the development of transistors entered a blowout period. Crystal purification technology, lithography technology and other comprehensive outbreak, can be said to be changing with each passing day.

In terms of industrial landing, Western Electric, the manufacturing arm of AT&T, quickly achieved mass production of transistors. It is widely used in telephone routing equipment, circuit oscillator, hearing aid and TV signal receiver.

Workers who are producing transistors in 1953, the first batch of battery-type transistor radios were put on the market. After listing, it was warmly welcomed by the people and the sales were booming.

In 1954, the world's first transistor computer, TRADIC, was put into use in the United States Air Force. Its operating power consumption is no more than 100W and its volume is no more than 1 cubic meter, which is very different from the ENIAC at that time.

TRADIC1954, known as a supercomputer, sold 17 million germanium transistors and 11 million silicon transistors in the United States by 1956, worth about $55 million.

It is worth mentioning that at the beginning, Bell Labs was the patent owner and the main holder of transistor technology. Later, because of the US antitrust law, Bell Labs actively granted semiconductor patents to other manufacturers. This has further promoted the popularization of semiconductor technology.

In 1956, the growing family of transistors, Shockley, Bardeen and Bratton won the Nobel Prize in Physics for their invention of the transistor.

The three bosses are famous in history. in fact, by this time, the founding team of transistors at Bell Labs had already fallen apart.

After the transistor was successfully developed, Walter Bratton applied for a change of department and went to another research group because he was unhappy with Shockley's suppression.

In 1951, John Bardeen left Bell Laboratories and went to the University of Illinois to become a professor. Later, he won another Nobel Prize for his contribution to the field of superconductivity.

In 1952, Gordon Thiel left to join Texas Instruments, helping the company become a future semiconductor giant.

In 1954, Shockley could no longer stay at Bell Labs and went to teach at the California Institute of Technology. Then, in 1956, he came to Mountain View in western California and founded Shockley Semiconductor Lab in a small city called Palo Alto (later part of Silicon Valley) to start a new business of his own.

No one expected that a few years later, Shockley would make the same old mistake again, forcing his eight apprentices away and becoming a loner again.

His eight apprentices, the famous "eight traitors", established after the departure of the "eight traitors", not only created the pattern of the world semiconductor industry, but also changed the trend of human history. (about their stories, you can see here: the Legend of Fairy Children)

"eight traitors", the eight gods of the chip industry, the above is the story of the birth of transistors. Limited to space, this article does not introduce the technical details of transistors in detail. Let's find an opportunity to introduce them later.

The content is relatively long, thank you for your patience. In the next article, Xiao Zaojun will tell you about the birth of integrated circuits and the patent war between Noyce and Kilby. Please follow us!

This article comes from the official account of Wechat: fresh Jujube classroom (ID:xzclasscom), author: Xiaozaojun

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