Xueba starts with change

Chapter 246 If you have half the speed, plus this quality...

At around 10:30 in the evening, Chen Zhou sent Zhang Yifan out of the room.

Zhang Yifan had to hurry back to school. According to him, their auntie, the housekeeper, was not too aggressive.

If you are locked out, writing a review is light.

Maybe they will be notified and criticized.

Seeing what he said was so serious, Chen Zhou naturally didn't dare to waste his time.

It's just that he is very strange. Aren't the housekeepers and aunts all amiable?
If you come back late, don't they always let you in quickly, for fear of delaying your rest?
Called a taxi for Zhang Yifan, watched him get in the car, and Chen Zhou went back to the room again.

As soon as he went back, he saw Shen Jing yawning.

Chen Zhou couldn't help laughing, he got up quite early today, and he didn't catch up on sleep on the high-speed rail, so he was really sleepy at this point.

"Senior, let's go back and rest first, the experiment at Institute 43 will officially start tomorrow."

"It's okay, I'll organize two more articles." After Shen Jing finished speaking, he yawned again.

He was really a little sleepy. If calculated according to the activity time of the day, he had not rested for nearly 16 consecutive hours.

"Okay, this matter is not in a hurry, we'll do it tomorrow." Chen Zhou said and went to help Shen Jing turn off the computer, urging him to go to sleep quickly.

Shen Jing glanced at Chen Zhou, packed up his things, and walked towards his room.

When he was about to go out, he stopped suddenly, turned to Chen Zhou and asked, "You won't stay up late to read documents, will you?"

Chen Zhou smiled softly: "No, I'll fall asleep after watching it for a while."

Shen Jing left suspiciously, but when he returned to the room, he felt something was wrong. What kind of concept does this kid have for a while?

After thinking for a while, Shen Jing turned on the computer again.

Work, work with focus, will counteract that tired sleepiness!

After cheering himself up, Shen Jing continued.

On Chen Zhou's side, after Shen Jing left, he sat back at the table and continued to read the documents.

There are two left, DC arc plasma jet CVD method and microwave plasma CVD method.

DC arc plasma jet CVD method, also called DAPCVD method.

This is a direct current arc plasma deposition method hidden in the discharge area.

The advantage of this method is that it has an extremely fast deposition rate.

It is extremely fast, not ordinary fast!
In the 90s, some laboratories achieved a high-speed growth of 930m/h by using a reactor with anode and cathode at right angles.

This is 930m/h, not 930μm/h!

Moreover, even if it is 930 μm/h, it is much higher than the 43 μm/h of the diamond film prepared in 40 now.

Not to mention 930m/h.

In contrast, one has the speed of a rocket and the other has the speed of a bicycle.

Maybe not even a bicycle.

It is also because of this high-speed growth rate that this method once became a hotspot method.

The preparation process is not complicated either.

The main thing is to apply a DC voltage between the rod-shaped cathode and the ring-shaped anode. When the gas passes through, an arc is triggered, the gas is heated, and the high-temperature expanded gas is ejected from the anode nozzle at high speed to form a plasma jet.

The gas used to start the arc is usually argon. After the plasma jet is formed, methane and hydrogen are introduced into the reaction gas. The methane and hydrogen are ionized and reach the substrate of the water-cooled deposition table to nucleate and grow diamond films on the substrate. .

Moreover, the preparation of diamond thin films by this method can not help but be fast, high-quality, and free from electromagnetic pollution.

However, due to the inhomogeneous temperature field due to the velocity and temperature field of the injected plasma, the film thickness in the deposition range is uneven, and the distribution will be trapezoidal.

When the deposition rate is too fast, the surface of the film will be uneven, which will greatly reduce the density of the film.

Seeing this, Chen Zhou smiled strangely: "It seems that too fast is not good..."

But overall, this method still has great research potential.

Chen Zhou took notes on the draft paper and put his thoughts aside.

After reading the relevant literature on the DAPCVD method, Chen Zhou swiped the mouse with his right hand and clicked to open a new PDF file.

The last preparation method.

Microwave plasma CVD method, that is, MPCVD method.

is the method adopted by 43.

It is also the purpose of Chen Zhou to search such documents.

It is only one year apart from the time when the DAPCVD method was reported.

This is also the most widely used method for depositing diamond films.

This method first uses an axial antenna coupler to convert 2-5W rectangular microwaves to form plasma under atmospheric pressure.

The high-pressure plasma will be sprayed from the "pinhole" of the coupler to the water-cooled sample stage, and then the diamond film will be formed.

The gas source used in the DAPCVD method is the same, mainly argon, and the reaction gases are methane and hydrogen.

Today, this approach has taken many forms.

However, whether it is the quartz tube type, quartz bell jar type and metal cavity type with microwave window according to the formation of the vacuum chamber, or the surface wave coupling type, direct coupling type and antenna type according to the coupling method of microwave and plasma Coupled.

Their deposition rate is related to microwave power.

For example, using the MPCVD method with a microwave power of 5kW, tool-grade diamond films can be deposited at a rate of 10 μm/h, heat sink-grade diamond films can be deposited at a rate of 8 μm/h, and optical-grade diamond films can be deposited at a rate of 3 μm/h.

When using 10kW microwave power, his deposition rate can reach 25μm/h.

That is to say, by increasing the microwave power, the deposition rate of the diamond film can be increased.

In addition, the deposition rate of the diamond film is also related to the gas pressure.

Under high microwave power, high volume flow ratio of methane and hydrogen, and 160 Torr gas pressure, a polycrystalline diamond film of 150 μm/h can be prepared.

If the pressure is increased to 310 Torr under the same conditions, a single crystal diamond film of 165 μm/h can be prepared.

"gas pressure……"

"Microwave power..."

Chen Zhou wrote down these two words on the draft paper.

I tapped twice with the pen, and drew two circles casually.

This is the point.

Putting down the pen, Chen Zhou slid the mouse and continued to read the content of the document.

The reason why the MPCVD method will become the most widespread method is that the quality of the diamond film prepared by this method is better than that of the DAPCVD method.

The problem of low density of the film is well solved, and at the same time, a large-volume diamond film can be produced.

In addition, this method can also deposit diamond films on curved or complex surfaces.

Moreover, the MPCVD method has no internal electrodes, which can avoid electrode discharge pollution and electrode corrosion.

It can be said that the conditions for preparing high-quality diamond films are met.

However, like the 43 lab setups, the deposition rate of the MPCVD method is flawed.

After reading this document introducing the MPCVD method in detail, Chen Zhou couldn't help thinking.

"If it has half the speed of DAPCVD method, plus the preparation quality of MPCVD method, wouldn't it be possible?"

　Dear book friends, I only got home at 10:30 tonight, and I am working overtime. Please forgive me, there will be another update later, you can read it tomorrow, good night.

　　
　
(End of this chapter)