Diamond Transistors-Any Being Made? - diyAudio
Go Back   Home > Forums > General Interest > Everything Else

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 23rd February 2007, 05:03 PM   #1
Wizard of Kelts
diyAudio Moderator
 
Join Date: Sep 2001
Location: Connecticut, The Nutmeg State
Default Diamond Transistors-Any Being Made?

Read an article some time ago about the use of diamond as a substrate for transistors, and I presume chips as well.

Any models coming close to the production line?

Also, does anyone have an idea what the forward voltage would be on a diamond transistor-like 0.6 V for silicon or 0.3 V for germanium? What would the voltage for a diamond transistor or diode be?
__________________
"A friend will help you move. A really good friend will help you move a body."
-Anonymous
  Reply With Quote
Old 23rd February 2007, 08:34 PM   #2
diyAudio Member
 
I_Forgot's Avatar
 
Join Date: Jan 2005
Location: Phoenix, Az.
I think it would be silicon on diamond substrate, so the transistors wouldn't change much. The big advantage to using a diamond substrate instead of silicon is that diamond is a much better thermal conductor. The problem is that silicon and diamond don't have matching crystal lattices so such pairings tend to be weak mechanically. Stresses due to differing thermal coefficients can cause the thing to fracture at the boundary.

I_F
  Reply With Quote
Old 23rd February 2007, 10:25 PM   #3
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
You can't use diamond as the actual semiconductor- the bandgap is waaaay too large. I-F has outlined the advantages as a substrate.
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
  Reply With Quote
Old 23rd February 2007, 11:23 PM   #4
Wizard of Kelts
diyAudio Moderator
 
Join Date: Sep 2001
Location: Connecticut, The Nutmeg State
Thanks. The article only touched on diamond's possible use in transistors. The main part of the article was about diamondlike coatings, and it even gave a project where a diamondlike coating could be cooked up in your home oven. It was the NY Times from way back.

Since then I was on the lookout for diamond transistors which didn't seem to be coming anytime soon. Now I know why.
__________________
"A friend will help you move. A really good friend will help you move a body."
-Anonymous
  Reply With Quote
Old 24th February 2007, 02:35 AM   #5
JohnG is offline JohnG  United States
diyAudio Member
 
Join Date: Mar 2002
Location: Upstate NY
I would not hold your breath. Diamond is a wide-bandgap semiconductor, and in theory one can make transistors. I think that currently, only experimental Schottky diodes have been made, although maybe a p-n junction diode has been fabricated by now. A BJT would probably have a BE drop about 3-4V. However, a MOSFET would not have such a voltage drop. The advantages of diamond semiconductors would be high voltage parts with low on-state voltage drop compared to silicon, and high temperature operation. Perfect for your direct-drive ESL...

Note that a silicon transistor on a diamond substrate may have some advantages, i.e. a highly thermally conductive insulating substrate, but ultimately it's still a silicon transistor.

Note that wide-bandgap devices are coming. SiC (silicon carbide) Schottky diodes are available from Digikey, and a number of researchers have fabricated SiC BJTs, JFETs and MOSFETs. I'm not a semiconductor designer, but my understanding is that the wafer quality and size is where silicon was decades ago, and the same properties that make wide band-gap materials attractive electronically also make them the devil to process. SiC has all kinds of crazy defects, and doping is by ion implantation or epi layer growth, since diffusion apparently doesn't work very well (temps to high?).

John
  Reply With Quote
Old 27th February 2007, 02:27 AM   #6
Wizard of Kelts
diyAudio Moderator
 
Join Date: Sep 2001
Location: Connecticut, The Nutmeg State
John:

Thanks for your informative answer.

Why is the work being done with silicon carbide? Does it contain properties similar to diamond but is more workable?
__________________
"A friend will help you move. A really good friend will help you move a body."
-Anonymous
  Reply With Quote
Old 27th February 2007, 02:53 AM   #7
JohnG is offline JohnG  United States
diyAudio Member
 
Join Date: Mar 2002
Location: Upstate NY
I'm really an end-user, but I'll answer as best I can. If anyone knows more, let me know.

SiC ( silicon carbide), like diamond, has a wide bandgap, which is good for high temperature and high voltage operation. It also has high thermal conductivity, although not as good as diamond. However, silicon carbide has a lot more process development behind it than diamond, and wafer sizes are increasing with decreasing defect density, meaning more devices per wafer and higher yield, both of which are driving the cost down. Like I mentioned before, SiC Schottky diodes are available from Digikey. These are great for switching power supplies, but I'm not too sure there are major benefits for anything under 200V.

Another big potential benefit of SiC is the ability to grow a silicon dioxide insulating layer. This is a huge natural benefit that is one of the main reasons standard Si technology has progressed so far. However, because of the carbon in SiC, and many other reasons I can BS about but don't actually understand, the oxide and the interface between the oxide and the SiC has a lot of room for improvement. That's why SiC MOSFETs are not commercial yet.

Diamond may be on the way, but my guess is it will be a while before anything is commercially available, and good transistors are probably a long ways off.

While this may not be of immediate help for audio, it is pretty interesting.

John
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Diamond Amp TimS Solid State 10 4th October 2012 06:15 AM
Diamond buffers Nordic Parts 7 13th March 2007 02:13 PM
Home Made Tubes?? has anyone made one, is it possible?? John Biles Tubes / Valves 7 11th December 2005 01:29 AM
diamond tip replacement djmiddelkoop Analogue Source 2 19th October 2004 06:44 PM
Diamond buffer peranders Solid State 45 15th November 2003 11:00 PM


New To Site? Need Help?

All times are GMT. The time now is 07:06 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2