this explanation makes pecvd as easily understandable as 1,2,3.

thank you very much. i am master student and only now understood the principle of this method! very simply and clear! thank you from Kazakhstan!

Nan you are such a great instructor.Thank you. watchig from Nairobi, Kenya, Africa.

Very simple and easy demonstration. Thumbs up.

Great video, thanks. Instantly subscribed! Kindest regards from Greece.

Thank you. A helpful introduation of PECVD

Thumbs up, great explanation.

excellent presentation

Thank you for lesson!.

very informative, thank you very much for the effort

Wonderful experience

This is a great, concise, understandable explanation. Wonderful!

@dukeuniversity-smif2466

4 жыл бұрын

Glad it was helpful!

If I’m not mistaken, I believe this is a similar process to synthetic diamond creation... diamond seed being the substrate and using carbon heavy gases

@BillDemos

2 жыл бұрын

Yeap! This is exactly the process. If you fill the chamber with methane (CH4, a carbon rich gas), you will get graphite deposited as it is mostly favoured to diamond sp3 bonds. However, having also hydrogen in the mix, eats away the graphitic phases and leaves only the SP3 bonds on the substrate. The mixture normally used is around 1% methane to 99% hydrogen. The same mixture analogy is also used when depositing very high quality silicon: 99% hydrogen to 1% silane (SiH4). This method is terribly slow and is more suited to making graphene, which is a single layer of diamond. To make bulk diamond, you should utilise techniques used to make bulk crystals: you melt carbon and then let it solidify. Carbon melts at 4500 degrees, so you either use the "skull" crubible technique, or materials that can withstand higher temperatures (there are some synthetic materials that have a higher melting point to carbon!). The only problem with carbon is that when it reaches its melting point it wants to sublime (directly evaporate from the solid phase), instead of going firstly into its liquid phase. To counter this, you have to keep it under pressure. Hence the "High Pressure High Temperature" name of this method. I am making a ver 3 vacuum chamber at the moment so that I show a few techniques on my channel for high quality advanced thin film deposition. Currently I only have electronic engineering videos but will soon get into material sciences.

@pawankumarverma7840

2 жыл бұрын

@@BillDemos Hii bill sir,. What is happening inside the plasma of reactive gases (CH4+H2), supplied by Rf power, inside pecvd system ???? pls. Can u explain... And how rf plasma created?? What is present inside the rf plasma, like charges, electron, methane molecules etc.

@BillDemos

2 жыл бұрын

@@pawankumarverma7840 Hi Pawan. A molecule, such as H2 for example, shares bonds between atoms. In that state, the atoms are happy as they are at their lowest energy. When you give them some energy, be it through raising temperature, or applying electricity, they become separated! So, from H2, two atoms in a molecule, you end up with all atoms separated! Not only that, but most atoms in a plasma also lose some of their electrons. So a plasma is a soup of mono-atomic species/elements and electrons. Once an atom loses its partners, it becomes very reactive, it wants to bond again with something. If it happens to reach the substrate where you are laying the diamond, it becomes part of it. You can make plasma in many ways. One way is to put electrodes in your chamber, and apply DC or AC high voltage. If the AC frequency is high, like in the range of millions of cycles per second, you call this RF plasma. The good thing with RF plasma is that it can be coupled to your system in a remote way: i.e. you don't need the electrodes within the system, but you can have them placed outside. This way, the metal that makes these electrodes does not contact and therefore does not contaminate the plasma.

Appreciate your explanation so much!!

@dukeuniversity-smif2466

3 жыл бұрын

Glad it was helpful!

Спасибо!

Excellent!

Clear and simple explanation! This was really helpful

@dukeuniversity-smif2466

3 жыл бұрын

Glad to hear!

@boonboom3528

3 жыл бұрын

I'm in awe of how smart and beautiful all women in Tech are! Not that they're mutually exclusive but I hope my daughter has an interest in STEM. I'm a construction Superintendent coming from a background in carpentry and I myself specialize in building laboratories for Biotech/LifeScience/Pharma/Medical etc and it seem that the majority of scientists/researchers are women but unfortunately, it seems that all the major execs are men. I usually have communications with the individual researchers just so I can insure individual lab space needs are met. I'm amazed at how passionate and brilliant they are and how they are changing the world around us

Very good 👍

What all substrates can be used in this process?

Great!

nice video

kindly tell us the price of this pecvd machine

Great 👍🏾

Hello, what size are the nanoparticles of molten gold emitted when evaporating due to high temperature?

@noellemassa4593

Жыл бұрын

i was going to ask the same thing!

thanks alot.... but where is the rest of series..etching techniques????

@dukeuniversity-smif2466

3 жыл бұрын

You can find the rest of this series in our Coursera course. It is free to access! www.coursera.org/learn/nanotechnology

What radio frequency is used for the plasma? It's voltage pulsed with RF right? If so, what's the freq range? Thanks

@dukeuniversity-smif2466

3 жыл бұрын

The RF generator utilizes 13.56 MHz. This is a popular frequency for laboratory RF applications and is one of the frequencies reserved in the ISM radio band (Industrial, Scientific and Medical). The ISM band is observed internationally and is regulated in the US by the FCC.

@Drew_Hurst

3 жыл бұрын

@@dukeuniversity-smif2466 Very interesting! Surprised it isn't higher. Appreciate the extra info. Thanks for Your reply

Greate info but Ms.Adithi don't make presentation like reading book

Does this make Duke important?

😊

"Clean the chamber so its ready for the next user." Ha!

Hii mam,. What is happening inside the plasma of reactive gases (CH4+H2), supplied by Rf power, inside pecvd system ???? pls. Can u explain... And how rf plasma created?? What is present inside the rf plasma, like charges, electron, methane molecules etc.