You can use your phone now, all thanks to a sentence he said 50 years ago

On March 24, 2023, American scientist and entrepreneur Gordon Moore passed away at the age of 94. Gordon Moore was a real "big boss", a promoter of human technological development, and a master who influenced the entire computer industry. Moore's Law, as Mr. Moore's greatest achievement, not only promoted the rapid development of computer technology and enabled computers to be more widely used, but also had a profound impact on the development of human science.

Gordon Moore, Image source: Wikipedia

At this point, all of the "Eight Traitors" of Fairchild who had run away from Dr. Shockley had passed away, and their era had ended, but the precious wealth they brought to mankind made them immortal.

01

"Traitors" take the lead in "rolling" chips

The story begins with William Shockley at Bell Labs, where he co-invented the transistor and won a Nobel Prize in Physics.

William Shockley, Image source: Wikipedia

In order to make more money, Shockley founded his own laboratory, Shockley Semiconductor Laboratory, in 1955. The laboratory is located in Palo Alto, California, USA.

Shockley Semiconductor Laboratory, Image source: Wikipedia

You may be a little unfamiliar with this city, but it has incubated many giant companies and is still the headquarters of many companies today. It has a more well-known name - Silicon Valley .

Shockley was an excellent physicist, but he did not have rich business experience and excellent management skills. After only six months of the company's establishment, many employees were extremely dissatisfied with him. On September 18, 1957, Robert Noyce and seven colleagues from Shockley's Semiconductor Laboratory collectively submitted their resignation letters to Shockley.

Shockley was furious at the time and denounced these eight young people as ungrateful traitors. This is the origin of the "Fairchild Eight Traitors". What Shockley did not expect at the time was that these people would become legends in Silicon Valley in the future. Later, even Shockley himself changed his words and called them "Eight Genius Rebels".

A group photo of the "Traitorous Eight", from left to right: Gordon Moore, Sheldon Roberts, Eugene Kleiner, Robert Noyce, Victor Grinich, Julius Blank, Jean Hoerni and Jay Last. Image source: Wikipedia

After leaving Shockley, the "Eight Traitors" founded the famous Fairchild Semiconductor Company . The name Fairchild is closely linked to Silicon Valley. It is no exaggeration to say that the founding of Fairchild Semiconductor Company marked the birth of Silicon Valley.

In 1968, due to a series of problems brought about by the rapid development of Fairchild Semiconductor, history repeated itself. Moore defected from Fairchild and founded Intel with Robert Noyce, the inventor of the integrated circuit, and Andy Grove, thus starting the road to the "Trinity Intel Legend".

In 1965, Moore was invited by Electronics magazine to write "Putting More Components on Integrated Circuits". In this article of only 4 pages, Moore sorted out several years of data and wrote the famous Moore's Law: In the next ten years, the number of transistors per unit area of ​​chips will double every year.

In 1975, Moore may have found that this speed was too fast, so he changed Moore's Law to doubling every two years .

The paper states that the number of transistors per unit area on a chip will double every year over the next decade. Image source: "Putting More Components into Integrated Circuits"

Perhaps even Moore himself did not expect that these few lines of words would become the development law of semiconductors in the next half century and be pursued by the whole world.

The famous Moore's Law of doubling every 18 months was actually modified by David House, the later CEO of Intel. He not only changed the time, but also misinterpreted doubling the number of transistors as "doubling performance". After the birth of Moore's Law, semiconductor companies around the world started the path of "involution" in the industry. Moore's Law in the commercial era became a promotional tool and an economic law.

02

Moore's Law

Transistor "slimming down"

Why can the number of transistors double in a short period of time? Why can Moore's Law hold true? These questions start with transistors.

A transistor is like two diodes connected end to end. The two sides are semiconductors of the same type, and the middle is another type of semiconductor. Under normal circumstances, no current can pass through it, but when we apply current to the semiconductor in the middle, as long as the current reaches a certain threshold, the transistor is turned on, which is equivalent to opening a switch, and below the threshold, the transistor is equivalent to a circuit breaker.

This ability to achieve free switching by regulating current is the most important function of the transistor, which opens the door to digital electronics and digital storage.

Transistors of different sizes, Image source: Wikipedia

Humans combine many transistors with other components to form various types of logic circuits - AND, OR, NOT gate circuits, which can be combined into various computing functions. Compared with ordinary circuits, this kind of circuit not only has faster computing speed, but can also be made very small, which is convenient for integration into various micro devices. This is the so-called integrated circuit , which is the "ancestor" of the modern Internet and the computers and mobile phones around you.

The more transistors there are, the more logic circuits they can form, and the more numbers we can calculate at the same time, thus forming faster integrated circuits. This is why large-scale and even ultra-large-scale integrated circuits were born.

Transistors inside an integrated circuit, Image source: Wikipedia

From the above description, you can find that under the same chip architecture, the number of transistors actually determines the performance of the chip . So how to double the number of transistors per unit area of ​​the chip? The answer is actually very simple, just reduce the area of ​​each transistor to 1/2 of the original.

Early chips were only arranged in two dimensions. If we consider the transistor as a rectangle, as long as its length and width are reduced to 0.7 times of the original, 0.7×0.7=0.49, the area of ​​a single transistor can be reduced to half of the original size. If the length and width of the transistor are reduced to 0.7 times of the original, its gate length will naturally be reduced to 0.7 times of the original.

Copyright image, no permission to reprint

What is a gate? The gate in a transistor acts like a fence, which can block electrons or allow them to pass through. Its function is to adjust the current flowing through the transistor by adjusting the current of the gate.

The gate is actually the core of the transistor function , so scientists choose to use the minimum gate length as a measure of process progress, which is often referred to as chip manufacturing process in commercial propaganda. Now you should know why the chip manufacturing process promoted by mobile phone manufacturers (from 14 nanometers, 10 nanometers to 7 nanometers and then to 5 nanometers) is reduced by 0.7 every time.

Of course, due to the invention of three-dimensional transistor stacking technology, the advancement of chip frequency and physical limits, the number of transistors in today's chips can no longer be "rolled up", and Moore's Law of doubling transistors cannot be achieved . So Intel reluctantly changed Moore's Law to "double the performance". The so-called chip process has also become a symbolic meaning , a marketing method created to follow Moore's Law, and no longer represents the minimum gate length of the actual chip.

The semiconductor industry has been developing in accordance with Moore's Law for more than half a century. From the 2,250 transistors in the first commercial chip to the tens of billions of transistors contained in a small CPU today, they are all the crystallization of the wisdom of thousands of engineers. Semiconductor manufacturers are becoming more and more "competitive", the number of transistors is increasing, the chip performance is constantly improving, and the price is naturally reduced. Now you can enjoy the rapid changes and innovations in technologies such as the Internet and smartphones, which are inseparable from human adherence to Moore's Law.

03

Moore's Law

Is it going to disappear?

Unfortunately, with the continuous introduction of new process nodes, the process technology is gradually approaching the physical limit, making Moore's Law unsustainable.

As for the reason why Moore's Law has reached its limit, the one you may hear most is the quantum tunneling effect . If transistors continue to shrink, they may even reach the size of a few atoms. At this scale, the quantum effect will be greatly enhanced. At this time, there is no need to apply current to the gate, and some electrons can flow directly from the emitter to the collector, which means that the function of the transistor is greatly weakened, which will lead to very serious consequences.

Copyright image, no permission to reprint

In order to continue to reduce the size of the gate, humans have also proposed various solutions, such as replacing the gate material with a high dielectric material to prevent electron penetration, or making the gate into a forked 3D structure similar to a fish fin, using a three-dimensional structure to replace the planar device to enhance the control ability of the gate, so as to reduce the impact of quantum tunneling on the chip.

But these methods are just "delaying tactics". If there is no breakthrough in materials science, as the number of transistors increases, production costs will continue to increase, and the performance improvement of transistors will also encounter bottlenecks. One day Moore's Law will "die" .

Some predict that the limit of Moore's Law will come around 2025, but some optimists believe that it can last longer. In recent years, with the advent of the AI ​​era, there has been more and more discussion about the death of Moore's Law. In fact, Moore himself has foreseen the day when Moore's Law will fail.

As early as 2015, Moore said in an interview that Moore's Law would not be valid forever, but if good engineering technology was applied, Moore's Law could still last for 5 to 10 years. Interestingly, Intel does not agree with the old leader's view, and they often say in public that Moore's Law is "alive and well."

Although it is an indisputable fact that the increase in the number of transistors has slowed down, major manufacturers are still working hard to keep up with Moore's Law. In the future, humans may improve the performance of transistors by optimizing hardware structure and using more efficient materials, or adopt new computing architectures, such as quantum computers and neuron computers, to meet the needs of different fields and applications.

As AI is experiencing the "Cambrian Explosion", we need more powerful, faster, and more energy-efficient chips to support more complex, smarter, and more innovative AI systems. The CEO of the company that developed the popular ChatGPT once posted on social media that a new version of Moore's Law - the global AI computing power doubles every 18 months - is coming soon. This may be the best tribute to Mr. Gordon Moore.

04

Conclusion

In this rapidly changing era, people's expectations for technology are constantly increasing. The introduction of Moore's Law has filled people with infinite imagination and expectations for future technology. From electronic computers to quantum computers, from traditional Internet to blockchain technology, computer technology is evolving at an astonishing speed, constantly changing the human world and life. Therefore, we need to constantly look for new technologies and methods to promote the advancement of computer technology.

But at the same time, we also need to be aware of the complexity and diversity of the development of computer technology and should not rely too much on the predictions and promises of Moore's Law. Only by continuous innovation and exploration can we achieve the leapfrog development of computer technology and the prosperity and progress of human society.

References:

[1] Moore, GE (1965). Cramming more components onto integrated circuits. Electronics, 38(8), 114-117.

[2] CEA-LETI. (2020). Leti's roadmap to overcome limitations of Moore's law. Retrieved from

[3] Denning, PJ (2013). Great principles of computing. Communications of the ACM, 56(9), 34-42.

[4] Wu Jun. “The Mystery of Silicon Valley”[J]. East China Science and Technology, 2016, No.359(01):79.

Review: Science Popularization China

Author: Wang Zhihao (Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences)

Producer: China Science Expo

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