Chapter 152 Topological Semimetal
Chen Yuanguang did not correct what the other party said about the photosensitivity of the silicon wafer. The photolithography machine first acted on the photoresist, and then printed the pattern on the silicon wafer through the etching process.
After all, the other party is just the person in charge. What he needs to do is to explain clearly why topological semi-metal can become a path.
“Topological semimetals describe a class of substances. Just as iron compounds include a variety of compounds containing iron elements, different topological semimetals, like different iron compounds, will exhibit different properties.
What we need to find is a topological semimetal that exhibits light sensitivity.
Scientists have always placed high hopes on topological semimetals, believing that this material will replace silicon wafers and become the basis of future chip technology because topological semimetals can exhibit a very special property: a broad spectrum effect.
The zero-band gap structure existing in the semi-metal can absorb excitation photons of various energies. It is sensitive to the polarization of the laser. The source of its linear polarization resolution comes from the anisotropy of the crystal lattice, which leads to topological semi-metals. Many metallic materials have significant photoelectric response mechanisms that are sensitive to linear polarization, resulting in photocurrent responses with significant anisotropy.
For example, the chirality of the Weyl cone makes it easy for electrons in semimetals to interact with the spin angular momentum of photons during the transition process, forming a unique selection rule and producing circularly polarized light. Current, such as the photocurrent response of some semimetals, is enhanced by the huge Berry curvature near the Weyl point of the Weyl semimetal. "
Lin Jia looked confused when she heard this. What is this? She did her homework yesterday after listening to Chen Yuanguang's lecture on topological semimetals, but she found that the homework she did seemed to be of no use at all.
Although Zhao Pu has a PhD in engineering, there is a gap between PhDs. The gap between his PhD and Chen Yuanguang's is much wider than the gap between Erben and Qingbei.
Not to mention topological semimetals, which have never been understood at all. This is a field that combines materials science, optics and condensed matter physics, and is considered a very cutting-edge field.
Zhao Pu felt dizzy when he heard it. He couldn't even understand the principle. He felt like he was listening to a book from heaven.
“Dr. Chen, I don’t understand what you are talking about at all.
But I guess you mean that topological semimetals are photosensitive because of their characteristics, so the photolithography machine can Is this what it means to act on it?" Zhao Pu said with a bitter smile.
Chen Yuanguang nodded: "Yes, I have discovered a material that is more sensitive to light than the topological semimetals previously discovered, and at the same time, it is more stable in terms of light sensitivity. .
This is a very difficult property to find because it is a semi-metal in an intermediate state between a metal and an insulator, which means it is unstable and unstable. If you use its light-sensitive properties to draw pictures, it will be difficult to achieve the pattern you expect. Stability appears above.
If we use a metaphor to describe it, you can understand it as rice paper, and any ink will render a large area on it, while the silicon wafer is A4 paper, and the ink will be very stable when printed on it.
Yes, it’s rice paper! "
Chen Yuanguang felt that he finally found a suitable metaphor so that the two people in front of him could understand what he wanted to express.
" Rice paper is thin and A4 paper is thick, so on rice paper Writing is unstable, but the pictures and text written on A4 paper are very stable.
And now I have found a new material that has the thinness of rice paper and the stability of A4 paper.
This also explains the question you just raised, that is, this material can be industrialized on a large scale.
Of course it also has some problems, but I have thought of solutions to these problems.
The biggest problem is that we need to transform the light source and the light source of the lithography machine. Previously, the light source of the lithography machine acted on the photoresist, and we need polarized light.
The other thing is that we need to carry out large-scale preparation of the topological semi-metal process. ”
Chen Yuanguang's answer solves two problems. One is that topological semimetal will show photosensitivity to polarized light, so it can be used with photolithography machines.
But the light source needs to be modified.
The second one is that this is industrial production technology.
“In addition, if we only solve the production end, we also need the design end and chip design, because we can make the chip larger and use the transistors used in the 7nm process to make a larger silicon wafer using 28nm. on.
Because I don’t know much about chip design, I think this still requires a redesign of the chip.
Especially this involves completely new processes. "
After hearing this, Zhao Pu knew that with Chen Yuanguang's character, since he said this, it means that he is absolutely sure of success.
"I will help you contact Yanjing. , and then prepare experts to make demonstrations. After completing the demonstration, if feasible, we will make selections among these domestic enterprises and research institutions.
We regard this as our top priority in recent years. ”
For China, the chip issue is of vital importance, and this can be felt whether it is the large integrated circuit industry fund or the support given to semiconductor manufacturers such as Huawei, SMIC, and Hua Hong.
Syngenta's fundraising scale of RMB 70 billion cannot be listed in an IPO. Syngenta relies on central enterprises and Huahong raises RMB 20 billion. After the fundraising is completed, the money can be put in the bank to earn interest.
Chip companies are now their own sons, and everything from policies to financial support illustrates this point.
For example, the photolithography factory plan was hyped by self-media bloggers but nothing was done. Why? Because this technical route has not been proven to be feasible.
In other words, by following the route of the lithography machine and crossing the river by feeling the stones, you can know what difficulties you will encounter and how to overcome them. The input-output ratio is relatively clear.
As for the photolithography factory, how to calculate the input-output ratio? This is a big project. After the money is invested and the results are not achieved, who is responsible, who signs the words, who approves the money, no one dares to make a decision.
After the introduction of room-temperature superconductivity, it was still a project that Shuimu University took advantage of and took advantage of cutting-edge technology.
It is said that the original success rate may have been only 50%. With the emergence of room temperature superconductors, the success rate has increased to 70%. It is also related to encouraging innovation.
It took a lot of effort from Shuimu University.
Zhao Pu has this acumen. He can keenly realize that Chen Yuanguang's plan is based on the transformation of the existing foundation, which means that it only takes a small cost to verify whether it is feasible.
Compared with photolithography factories, it is much less difficult to modify the light source. Even the plan of the photolithography factory will be allowed, not to mention the photolithography machine transformation plan of Chen Yuanguang, who has room temperature superconducting technology.
"Mr. Li, is this through magnetic doping strategy or compatible sputtering support?" Lai Jiachen is a professor at Shenhai Jiaotong University who is engaged in topological semimetal research, and is a young person in this field.
He graduated with a Ph.D. from the University of Minnesota. He originally thought this was just a routine business trip, but what he saw reshaped his outlook.
Hua’s technology is actually so advanced?
In his laboratory in Mianyang, he saw a topological semimetal with both photosensitivity and stability. What’s more, this thing is in the form of a film.
"Sorry, I don't know either. I'm just a clerical staff member. I'm here to help you with your work and life in Mianyang. Although I also graduated with a master's degree in materials science, that stuff is too high-end and I can't know about it." The man he called Mr. Li said calmly.
He was responsible for receiving the three professors, and he was already familiar with this rhetoric. When these people came and saw this material, they all looked shocked. They had to find out which group made it and what technology was used. How is it done to maintain a balance between stability and photosensitivity?
Every time he heard this question, he wanted to roll his eyes. If he could figure it out, he would have chosen to study for a Ph.D. instead of going to Shu Province as a transfer student after graduating with a master's degree.
Combining these two properties into a thin film, Lai Jiachen easily thought that this thing could be used in chip manufacturing. Everyone has always had high hopes for topological semimetals because of their potential in chips.
Lai Jiachen graduated from the University of Minnesota. The university has a group that is doing very well in the field of topological semimetals. He did his PhD and postdoctoral work in that group.
Because some of his junior students from the Ph.D. period are still studying there for post-doctoral studies, and some are still in Minnesota. He also has many acquaintances in that group. He knows that they have recently made good results in topological semimetals and made A topological semi-metallic thin film with ultra-low energy consumption.
The paper was published in the journal Nature Communications, but the topological semimetal he saw in the Mianyang laboratory was ten years ahead of what they had built. Ten years was a conservative estimate.
All the way home from this trip, Lai Jiachen was still thinking about how this thing was made, what the process was, and which group in China was so awesome.
Lai Jiachen has always believed that the reason why he was able to teach at SJTU and rank among the top 1,000 young people in China was because the country lacked talents in the promising emerging field of topological semimetals.
Now I realize something is wrong. China is so good at topological semimetals. A postdoc with his level cannot get an associate professor position at Shenhai Jiaotong University when he comes back. I will give him a promotion or leave. young teachers.
"Professor Lai, if you are willing to participate in this project, please sign these documents. We will coordinate with Shenhai Jiaotong University to allow you to participate in the project.
If you are not willing, you can just You need to sign a confidentiality agreement, and then you can go back. Tell me your time and I will help you book your flight." The staff member named Li said politely.
Lai Jiachen asked curiously: "Do I just need to sign a confidentiality agreement?
According to this time, you are so mysterious that you can't even reveal who made it, and you don't know the process or parameters. You have to test it yourself. If it weren’t for the Arabic numerals on it, I would have thought that the country had dug up an alien spacecraft. This was materials picked up from the alien spacecraft.”
The staff member surnamed Li still remained polite. Smile: "Professor Lai, we have no hope of keeping it secret.
You should know that this will be applied to chips. Mr. Zhao explained to you when I came here that this is a big project that requires the cooperation of tens of thousands of upstream and downstream engineers, including chip design, laser production, optical lenses, etc. Needless to say, it requires the coordination of dozens of suppliers, and it is impossible to keep it confidential.
Of course, this does not mean that signing a confidentiality agreement is just a formality. Once we find that you have leaked secrets, we will have a basis for subsequent accountability. "
Lai Jiachen continued to ask: "You really don't mean to force me? "
The staff member named Li smiled bitterly: "Professor Lai, of course not. If there was any intention of forcing it, I wouldn't be talking to you.
This project involves a long time and requires a lot of coordination. What we need is not just one or two people, but hundreds of people. We don’t want to force it. ”
Lai Jiachen asked again: "Is it true that you just said to retain the establishment?"
Staff surnamed Li: "Of course it is true. This is a project led by the national level. After the follow-up project is over, you still have to return to your original job." Unit, you won’t agree even if you want to be here.”
He thought to himself, unless you can become the project leader, but this is obviously impossible.
The organization does not mean to force the transfer. It is just a discussion. A group of people are needed to participate in the mass production of topological semi-metal. Because this is completely a cutting-edge emerging field, no one knows it, and it means starting from scratch.
Lai Jiachen thought to himself that this is actually a jump from academia to industry.
He is still very interested in being able to retain the establishment, which means there is no risk. Anyway, if the project fails, it will just be returned to the university.
Furthermore, this kind of opportunity is too rare. When Fairchild started in Silicon Valley, they were also a group of researchers who jumped from academia to industry, and finally made epoch-making achievements. Intel, AMD, and Texas Instruments were all born in That wave of PC.
Lai Jiachen believes that this new material has great potential, and experience is very important. Being an associate professor at Jiaotong University means only a few million in research funds a year, and you have to compete with others to use instruments.
Work here, with multi-billion projects, equipment at your disposal, and the direction is cutting-edge, ten years ahead of Americen. Once the industrialization is successful, you can jump to the industry and earn an annual salary of millions. Take whatever you want.
The material was tested by himself. As an expert in the field, he is very aware of the potential of this thing in the chip field.
Lai Jiachen thought for a long time and couldn't think of a reason for rejection. The only reason was his wife. It was impossible for his wife to come to Mianyang when she worked in Shenhai.
This is a problem, but the other party also said before that he can go back for one month of vacation a year, and his wife can also come over. It is very convenient to have direct access to the airport.
Thinking of this, Lai Jiachen immediately agreed: "I choose to stay, when will we start working?"
The staff member named Li was not surprised at all that Lai Jiachen stayed. These professors Seeing this material is no different from seeing a beautiful woman. I can't resist the temptation at all.
“We will start working after we settle down. I will assign tasks to you then and wait for arrangements.”
Lai Jiachen continued: "Now we can say who developed this material, right? I have too many questions and want to chat with him."
"It's the one you guessed, Professor Lai. I’m telling you in advance that you can see him even if you stay here for a few days without breaking the rules.”
. . Failed every day, will update tomorrow
(End of this chapter)