Volume 1: Student Life Chapter 246: If it has half this speed, plus this mass...
At around 10:30 in the evening, Chen Zhou escorted Zhang Yifan out of the room.
Zhang Yifan had to hurry back to school. According to him, their dormitory manager was extremely fierce.
If you are locked out, writing a self-criticism is the lightest punishment.
If you are not careful, you may even be criticized in a notice.
Seeing that he was speaking so seriously, Chen Zhou naturally did not dare to waste his time.
But he was very confused. Aren’t all dormitory managers kind and friendly?
If you come home late, don’t they let you in quickly, for fear of disturbing your rest?
Chen Zhou called a taxi for Zhang Yifan and watched him get in the car before returning to the room.
As soon as I got back, I saw Shen Jing yawning.
Chen Zhou couldn't help but smile. He actually got up quite early today and didn't catch up on any sleep on the high-speed train. So at this point, he was indeed feeling a little sleepy.
"Senior, go back and rest first. The experiment of Institute 43 will officially begin tomorrow."
"It's okay, I'll organize two more articles." Shen Jing said, and yawned again.
He was really a little sleepy. If calculated based on the daily activity time, he had not rested for nearly 16 hours.
"Okay, there's no rush for this. Let's deal with it tomorrow." Chen Zhou said as he went over to help Shen Jing turn off the computer and urged him to go to bed quickly.
Shen Jing glanced at Chen Zhou, packed up his things, and walked towards his room.
Before leaving, he suddenly stopped, turned around and asked Chen Zhou: "You are not staying up late to read the literature, are you?"
Chen Zhou smiled softly and said, "Not really. I'll just watch for a while and then I'll go to sleep."
Shen Jing left doubtfully, but after returning to the room he felt something was wrong. What on earth was the concept of this kid's "a while"?
After thinking for a while, Shen Jing turned on the computer again.
Work, focused work, will offset the tiredness and sleepiness!
After encouraging himself, Shen Jing started to continue.
As for Chen Zhou, after Shen Jing left, he sat back at the table and continued reading the documents.
There are two left, DC arc plasma jet CVD and microwave plasma CVD.
DC arc plasma jet CVD method, also called DAPCVD method.
This is a DC arc plasma deposition method with a hidden discharge zone.
The advantage of this method is that it has an extremely fast deposition rate.
It’s extremely fast, not just ordinary fast!
In the 1990s, a laboratory achieved a high-speed growth of 930m/h using a reactor with anode and cathode at right angles.
This is 930m/h, not 930μm/h!
Moreover, even if it is 930μm/h, it is still much higher than the 40μm/h of diamond film currently prepared by the 43rd Institute.
Not to mention 930m/h.
In comparison, one is as fast as a rocket and the other is as fast as a bicycle.
Maybe not even a bicycle.
It is also because of this high growth rate that this method once became a hot method.
The preparation process is not complicated.
The main process 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, heating the gas. 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, the reaction gases methane and hydrogen are introduced. The methane and hydrogen are ionized and reach the substrate of the water-cooled deposition table, where they nucleate and grow diamond films.
Moreover, this method of preparing diamond films is not only fast, but also of high quality and has no electromagnetic pollution.
However, due to the uneven temperature field of the jet plasma, the film thickness within the deposition range is uneven and has a trapezoidal distribution.
When the deposition rate is too fast, the surface of the film is uneven, which will greatly reduce the density of the film.
Seeing this, Chen Zhou smiled strangely: "It seems that it's not good to be too fast..."
But overall, this method still has great research potential.
Chen Zhou was taking notes on a piece of scratch paper and writing down his thoughts.
After reading the relevant literature on the DAPCVD method, Chen Zhou slid the mouse with his right hand and clicked on a new PDF file.
The last preparation method.
Microwave plasma CVD method, also known as MPCVD method.
This is the method adopted by the 43rd Institute.
This is also the purpose of Chen Zhou's search for such documents.
The DAPCVD method was reported only one year apart.
This is also the most widely used method for depositing diamond films.
This method first uses an axial antenna coupler to convert 2 to 5 W rectangular microwaves to form plasma under atmospheric pressure.
The high-pressure plasma will be ejected from the "pinhole" of the coupler onto the water-cooled sample stage, thereby forming a diamond film.
The gas source used in the DAPCVD method is the same as that used in the DAPCVD method, which is mainly argon, and the reaction gases are methane and hydrogen.
Today, this approach has taken many forms.
However, whether it is divided according to the formation of the vacuum chamber, such as quartz tube type, quartz bell type and metal cavity type with microwave window, or according to the coupling method of microwave and plasma, such as surface wave coupling type, direct coupling type and antenna coupling type.
Their deposition rates are all 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 10μm/h, heat sink-grade diamond films can be deposited at a rate of 8μm/h, and optical-grade diamond films can be deposited at a rate of 3μm/h.
When using 10kW microwave power, the 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 diamond film is also related to gas pressure.
Under high microwave power, high methane to hydrogen volume flow ratio, and 160 Torr gas pressure, polycrystalline diamond films with a density of 150 μm/h can be produced.
If the pressure is increased to 310 Torr under the same conditions, a single crystal diamond film of 165 μm/h can be produced.
"Gas pressure..."
"Microwave power..."
Chen Zhou wrote down these two words on the draft paper.
He tapped twice with the pen and drew two circles.
This is the key point.
Putting down the pen, Chen Zhou slid the mouse and continued to read the contents of the document.
The reason why MPCVD has become the most widely used method is that it can produce diamond films of better quality than DAPCVD.
It not only solves the problem of low film density, but also can produce large volume diamond film.
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 contamination and electrode corrosion.
It can be said that the conditions for preparing high-quality diamond films are met.
However, just like the device in the 43rd laboratory, the deposition rate of the MPCVD method is a major drawback.
After reading this document that details the MPCVD method, Chen Zhou couldn't help but think.
"If we can achieve half the speed of DAPCVD and the same quality as MPCVD, then this will be possible, right?"
