Thin film selection for Diamond/Nickel interface

Click For Summary

Discussion Overview

The discussion revolves around selecting a suitable thin film and deposition method for a diamond and nickel alloy interface. The thin film must meet specific requirements, including strong adhesion, resistance to inter diffusion, thermal stability up to 700K, and decent thermal conductivity. Various deposition methods such as sputtering, evaporation, JDC, and CVD are considered.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that a typical film structure for solder attachment on diamond is Ti/Pt/Au, where Ti bonds with diamond, Pt prevents inter diffusion, and Au bonds well with solder.
  • Another participant mentions that chromium could be a strong candidate for bonding to nickel, but questions its inter diffusion properties with diamond.
  • There is a mention of using active brazing alloys containing titanium, which may meet the thermal requirements, though uncertainty remains about their effectiveness.
  • Concerns are raised about the adhesion properties of chromium to nickel and the lack of knowledge regarding its inter diffusion barrier properties.
  • One participant notes that nickel does not form a carbide under normal conditions, which may affect adhesion to diamond.
  • Another participant proposes graphite as a potential thin film material, though no further details are provided.

Areas of Agreement / Disagreement

Participants express various viewpoints on potential thin film materials and methods, but no consensus is reached regarding the best option. Multiple competing ideas and uncertainties remain in the discussion.

Contextual Notes

Participants highlight limitations in their knowledge regarding the inter diffusion properties of certain materials and the effectiveness of various deposition methods under specific conditions.

toasty1231
Messages
1
Reaction score
0
Hello everyone. My task is to select a thin film and deposition method that will achieve a few goals.
The thin film will be sandwitched between a diamond and nickel alloy. The thin film needs to:

  • Adhere to a diamond and nickel alloy strongly without inter diffusion.
  • Stay together up temperatures of 700K, and be decently thermally conductive.

The film can be deposited via standard methods like sputtering, Evaporation, JDC, CVD, ect...

I know that diamond and nickel have similar bond structures (sp3) and a thin film with a similar structure would help maintain a strong bond.

Any info would be greatly appreciated!
 
Engineering news on Phys.org
Typical film structure put down on diamond to enable solder attachment is Ti/Pt/Au. The Ti reactively bonds with the diamond surface, the Pt prevents inter diffusion, and the Au makes a good bond with solder.

There's some work with Cr as the first layer on diamond. It forms a carbide, so adheres to diamond. Don't know how it would stick to nickel, nor do I know about its inter diffusion barrier properties.

Most of the diamond adhesion systems I worked with were put on by sputtering. You have to have a good (low oxygen background pressure) sputtering system to successfully deposit Ti because it's very reactive and forms a super stable oxide if you have any background oxygen in the chamber.

An alternative might be active brazing alloys, which contain a little bit of Ti that combines with diamond and whatever else you're bonding to the diamond when the braze melts. I used some products from S-bond to attach copper microprocessor heat spreaders to CVD diamond plates and it worked reasonably well. I think there are active braze alloys that might make your 700°C requirement, but I'm not sure. I used the S-bond material because it was easier than waiting through the out of house sputtering service turnaround.

It probably doesn't help with adhesion that diamond and Ni have similar crystal systems. Ni doesn't form a carbide under normal conditions. Diamond abrasive makers sell Ni-coated diamond abrasives, so clearly they can stick Ni to diamond very well. They use fluidized-bed deposition, but I have no idea what the interface chemistry is.
 
hha
 

Attachments

  • 1.jpg
    1.jpg
    9.3 KB · Views: 642
I can't express any opinion! Thank you for the topic, I need the same answer!
 
Chromium is the first thing that comes to mind. It bonds strongly to to nickel and nickel is often used as a substrate for chrome surface treatments.
 
graphite?
 

Similar threads

How Can I Improve Au Anode Adhesion and Analyze Al Deposition Rates for OLEDs?
  • · Replies 11 ·
Replies
11
Views
3K