Great Country Academician

Half an hour was not long. While Xu Chuan was observing the lunar rock material through a scanning electron microscope, the test on the other side of the laboratory was also successfully completed.

The detection results of lunar rocks using ultra-high-resolution field emission scanning electron microscopy have been drawn into data tables and pictures.

After connecting the color printer and image printing equipment, Wang Hang, who was responsible for conducting the experiment, quickly printed out the relevant data charts.

"Academician Xu, Institute Zhao, the analysis results of the field emission scanning electron microscope have come out."

Taking the experimental data from the other party, Xu Chuan quickly read through it.

Compared with conventional scanning electron microscopy, ultra-high-resolution field emission scanning electron microscopy takes much longer.

But it can also see a lot more.

In particular, the equipment in Xinghai Research Institute uses the latest digital image processing technology to provide the latest level of high-magnification and high-resolution scanning images. It is valuable and can also bring more observations of the material itself.

Generally speaking, the scans of the lunar rocks in the Yaochi crater are almost the same as those observed with ordinary electron microscopes.

But the details are vastly different.

For example, the SED image of an ordinary scanning electron microscope can visually display the thickness of carbon nanotubes and the interweaving state between carbon nanotubes.

But in the field emission scanning electron microscope STEM image, you can see the small particle structure hidden in the 3D structure.

These granular structures cannot be seen in traditional scanning electron microscopy experiments.

In addition, field emission scanning electron microscopes also have unique brightfield image BF, darkfield image DF, and high-angle annular darkfield image HAADF modes, etc.

These images have different imaging advantages and can be used together according to the sample conditions, and the imaging results can be verified with each other.

Xu Chuan discovered something special on the high-angle annular dark field image HAADF of the moon rock in the Yaochi crater.

"It's a bit interesting. The trajectory and intensity of the secondary electrons of these carbon nanotubes in HAADF imaging have obvious differences between light and dark compared to light and dark field imaging."

After muttering something in his mouth, his eyes fell on a drawing in his hand, with a hint of thoughtfulness in his eyes.

When placed on a 1,000,000X magnification image, there is a clear difference in the brightness of the regular and neat carbon nanotubes.

There are some obvious changes in the energy response, composition contrast, and topography contrast data of HAADF imaging.

On the side, Zhao Guanggui frowned slightly and said: "This shouldn't be the case. Theoretically, HAADF imaging and BF and DF imaging will not have such a large difference in contrast and energy response."

Although the three imaging methods are different, and the images formed will also be different, it is rare for the energy and contrast to be so different.

Xu Chuan smiled and said: "There is nothing impossible. If these carbon nanotubes are doped with the underlying substrate, resulting in a structure similar to the semiconductor gates in integrated chips, these differences can be explained. "

Hearing this, Zhao Guanggui looked over in surprise and couldn't help but ask: "Are you saying that if there are differences in potential distribution on the surface of these samples, such as semiconductor-like P-N junctions, biased integrated circuits, etc., what will happen to them?" The difference in local potential affects the trajectory and intensity of the secondary electrons."

Xu Chuan nodded and said: "Well, at present, this guess is the most likely to explain this energy and contrast gap."

"Hiss~"

Zhao Guanggui took a breath and said in surprise: "If so, this is most likely a natural carbon nanotube integrated board?"

Staring at the experimental data report document in his hand, Xu Chuan pondered and said, "I don't deny this possibility, but the possibility that it is a natural carbon nanotube integrated circuit board is still very low in my opinion."

"Um?"

Hearing this, Zhao Guanggui and the other two researchers in the laboratory all looked at him with surprise and confusion.

According to the data on HAADF imaging, this is a very obvious potential contrast difference, and generally speaking, this difference usually only appears in semiconductors.

Because semiconductors have local potential differences, in the positive potential area, the secondary electrons seem to be pulled and difficult to escape. Therefore, in these areas, the secondary electron yield is less and the image appears darker;

On the contrary, in the negative potential area, secondary electrons are easily pushed out, the yield is higher, and the image appears brighter. This is the potential contrast.

Generally speaking, the analysis of semiconductor equipment, such as chips, from other countries is done through potential contrast.

(This is a structural diagram of a chip electron microscope, you can clearly see the differences inside)

Looking at the experimental report in his hand, Xu Chuan thought for a moment and explained: "Although judging from the scanned image, when the bias voltage is applied, the substrate has semiconductor properties to a certain extent."

"But there is still a big gap between it and carbon-based integrated tubes. From a material science point of view, I personally prefer that it is affected by external forces and is doped with some other materials, resulting in a difference in resistance. ”

"Looking at the third picture, you can clearly see that the carbon nanotubes in the third column have different molecular brightnesses."

After a slight pause, he continued: "But this direction can be studied to see what elements it is doped with. It would be good to learn from it."

Zhao Guanggui's eyes moved, staring at the experimental data in his hand and said: "Are you talking about the doping research of carbon semiconductors?"

Xu Chuan nodded, with a smile on his face: "Well, although the properties of carbon and silicon are similar, there are still big differences."

"Carbon is a conductor, and silicon itself is a semiconductor, so it is also a very difficult task to perfectly dope it and turn it into a stable carbon semiconductor."

"But now, the moon has pointed us in a direction."

"Although the carbon nanotubes in this material are not integrated carbon transistors, they are doped with other elements."

"Detect what the elements involved in these carbon nanotubes are, and then replicate them with high-purity carbon materials to see how the performance in all aspects is."

"Maybe it can also help us solve another problem of carbon-based chips."

Zhao Guanggui nodded and said: "I will arrange someone to do experiments in this area!"

It is not a rare thing to obtain research ideas and inspiration from natural materials or creatures in nature.

For example, geckos and mechanical claws, shark skin and ship coatings, swimsuits, maple seeds and drones, etc.

The moon rock in front of them can also give them some very good inspiration.

First of all, the neatly and tightly arranged carbon nanotubes are the most important discovery.

It is of great value for them to study how carbon-based chips can efficiently integrate carbon transistors.

Secondly, it is the microstructure discovered by field emission scanning electron microscope.

These carbon nanotubes in the moon rock have obvious doping phenomenon. It may be caused by changes in external temperature, pressure and other conditions.

This is also important for them to study how carbon nanotubes can make semiconductor switches with excellent performance.

In fact, the difficulty of carbon-based chips is not just the arrangement of carbon-based pipes.

Although it is the most difficult part, it does not mean that there are no other difficulties.

For example, carbon is a conductor and has conductivity. Both pure carbon and impure carbon can conduct electricity.

And controlling the defect-free structure of nanocarbon materials, transforming them into semiconductors, and controlling the purity of semiconductors have also become extremely difficult.

To be precise, carbon is more difficult to apply in semiconductors than silicon, and has more disadvantages.

In fact, it has to be said that silicon material is the best or most suitable material that humans can find in the field of chips.

The overall performance and adaptability of carbon, with current technology, is far inferior to that of silicon materials in terms of chips.

The talents cultivated by top semiconductor companies such as Intel, Applied Materials, Lamb Institute, and Dongjing Electronics are not stupid.

It is no exaggeration to say that most of the time, whether it is academia or major research institutes, whether it is an idea that comes out of the brain or an idea that comes out of a flash of inspiration, these companies have actually conducted preliminary research 20 or 30 years ago.

Then they will decisively give up because of this idea, or an irreparable defect of this material, or too high research difficulty.

For something like a chip, no matter how good other performances are, if one key indicator is not good, it will be directly killed.

For example, germanium is an example.

Germanium crystals have self-strain, are prone to thermal drift and cold drift, and make the chip less stable.

This point is enough to make germanium be directly abandoned by the industry on a large scale after the emergence of silicon.

The development of silicon-based chips to this stage is the optimal solution compromised by countless attempts and researches in the industry for decades.

At least it is the optimal solution in the current stage of technological development.

In this regard, the overall performance and evaluation of carbon cannot catch up with silicon.

Of course, this does not mean that carbon has no future.

On the contrary, the prospects of carbon-based chips are far greater than those of silicon-based chips.

Higher integration, faster computing speed, not affected by quantum effects, low energy consumption, low heat dissipation, high electron mobility, more suitable for high-frequency and overclocking operation than silicon-based chips, etc.

These are the advantages of carbon-based chips.

But it is difficult to manufacture.

Compared with silicon-based chips, the manufacturing difficulty of carbon-based chips is not one or two times greater at the current level of technology.

Whether it is the neat and stable arrangement of carbon nanotubes, the control of the purity of carbon semiconductors, or the purification of carbon nanotubes, they are all great problems.

So in contrast, silicon-based chips with lower technical requirements were undoubtedly the mainstream choice for research and development at that time.

Of course, path dependence is also a very important reason on the other hand.

In the past few decades, semiconductor technology, especially integrated circuit manufacturing technology, has been based on silicon-based products.

During this period, the whole world has invested and is still investing countless manpower and funds in technological advancement.

At this time, no one would be willing to change tracks unless there is a dozens of times advantage.

Although carbon-based chips are indeed better, to be honest, they do not have an advantage of dozens of times that of silicon-based chips.

So in the past, carbon was an abandoned material in the chip field.

It's just that this abandonment is different from other materials, such as germanium crystals.

Germanium crystals are abandoned because they have defects and their performance is not as good as silicon.

Carbon transistors were abandoned because the research and development technology was too difficult.

In the laboratory, after discussing the test data of the field emission scanning electron microscope, Xu Chuan returned to his office first with the test data of the field emission scanning electron microscope.

"Siyi, is Academician Chang Huaxiang now at the Institute or at the Xiashu Base?"

When passing by the assistant room, he asked the assistant Shen Siyi who was sorting out the documents in his hand.

"Academician Chang is now in charge of the lunar surface project at the Xiashu Aerospace Base. Do you need me to contact him?" Shen Siyi replied quickly.

"No, I'll just call him."

Waving his hand, Xu Chuan walked into the office, picked up the dedicated phone from the desk, and dialed the Xiashu Aerospace Base.

After contacting Academician Chang Huaxiang, he smiled and said, "Academician Chang, it's me. I have something to tell you."

On the other side of the phone, Chang Huaxiang nodded and said, "You tell me, I'll remember it."

"The Materials Research Institute has made significant discoveries while collecting lunar rocks for research on a mountain called 'Yaochi Crater'."

"Now I need to arrange personnel at the Xiashu Aerospace Base and the Lunar Outpost Research Station to conduct a most detailed investigation of this crater. I will have someone send you the relevant requirements later."

Speaking of this, he immediately added, "Oh, by the way, the priority of the project related to this investigation is S-class."

Hearing this, the expression on the face of Academician Chang Huaxiang on the other side of the phone changed, and he quickly replied, "Okay, I will have someone do the relevant work immediately after receiving the information."

In the research of Xinghai Research Institute, the level planning of the project is unified, roughly divided into six categories: S, A, B, C, D, and F.

Among them, F is the lowest level, which is a project derived from the ordinary research project of Class D, and the resources that can be mobilized are limited to the project itself.

If there are additional resources, they need to be reported to the D-type project first, and then the person in charge of the D-type project will apply for it.

And the S-level is the highest level.

For projects of this level, when there is a demand for resources, all departments of the entire institute need to complete resource integration and manpower arrangements as quickly as possible, and even suspend some of the original research and draw out human and material resources to cooperate with related work.

Chang Huaxiang can imagine how important the discovery on the moon is, as Xu Chuan can evaluate it as an S-level priority.

Although he doesn't know whether the other three major institutes have S-level projects, there are only two S-level projects in the Institute of Aerospace.

That's right, the Institute of Aerospace + Xiashu Aerospace Base can now be said to be the core and backbone of China's aerospace power, but there are only two S-level projects in hand.

They are the construction of the lunar outpost scientific research station base and the construction of the lunar orbital mass projector.

The lunar biosphere project, the manned Mars landing project, and even the previous second-generation space shuttle development, have not entered the S-level project, but are only evaluated as A-level. You can imagine the importance of this discovery.

It is no exaggeration to say that every S-level project in the Xinghai Research Institute can affect the development of the entire country and even the world.