SiC operation at high temperatures

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In summary: At higher doping concentrations you typically get reduced mobilities due to ionized impurity scattering.
  • #1
ZeroFunGame
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What is fundamentally preventing SiC BJTs and JFETs devices from operating at 1000C?
SiC BJT can operate at 500C and SiC JFET has shown to operate at 800C, due in part to their lack of a dielectric. What is fundamentally preventing SiC BJTs and JFETs devices from operating at 1000C?
 
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  • #2
Links please. Thanks. :smile:
 
  • #4
The same as for other semiconductors, and the publication you linked discusses this:
The advantage of a wide energy bandgap is that the intrinsic concentration is much lower, and therefore the intrinsic temperature is much higher. The intrinsic temperature can be calculated as the temperature at which the intrinsic concentration is equal to the lowest doping concentration in the semiconductor device
This temperature is not a hard upper limit but the behavior of the transistor will change in that range.

You also have to design all mechanical parts to withstand these temperatures, but with a custom design this shouldn't be what limits the temperature.
 
  • #5
Thanks mfb! What is preventing the continual doping to increase the intrinsic temperature then? Seems like the hotter the environment, the higher the intrinsic concentration, then just increase the doping to offset reaching the intrinsic temperature?
 
  • #6
Strong doping comes with its own disadvantages but I don't remember what exactly now.
 
  • #7
I guess it would just become more and more conducting, which leads to further leakage and higher junction temperatures and power dissipation reducing device reliability. Just an initial guess.

Thinking about this some more, i suspect that the ohmic/shottky contacts between metal and SiC will degrade as well, but looking for further feedback from the community regarding good resources for this topic! Thanks!
 
  • #8
ZeroFunGame said:
I guess it would just become more and more conducting, which leads to further leakage and higher junction temperatures and power dissipation reducing device reliability. Just an initial guess.

Thinking about this some more, i suspect that the ohmic/shottky contacts between metal and SiC will degrade as well, but looking for further feedback from the community regarding good resources for this topic! Thanks!
At higher doping concentrations you typically get reduced mobilities due to ionized impurity scattering.
 
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  • #9
Vagn said:
At higher doping concentrations you typically get reduced mobilities due to ionized impurity scattering.

What's the minimum mobility needed for digital computation?
 
  • #10
Vagn said:
At higher doping concentrations you typically get reduced mobilities due to ionized impurity scattering.

Also, would there be an appropriate ratio of doping concentration vs intrinsic carrier concentration that would be appropriate for IC applications?
 

FAQ: SiC operation at high temperatures

1. What is the maximum temperature at which SiC can operate?

SiC can operate at temperatures up to 600 degrees Celsius without significant degradation, and can even withstand temperatures up to 1000 degrees Celsius for short periods of time.

2. How does SiC perform at high temperatures compared to other materials?

SiC has a higher melting point and thermal conductivity compared to traditional materials like silicon and gallium nitride, making it a more efficient and reliable option for high temperature applications.

3. What are the main challenges in operating SiC at high temperatures?

The main challenges include maintaining stable electrical properties, managing thermal expansion mismatch, and preventing surface degradation due to oxidation or other chemical reactions.

4. What are the benefits of using SiC at high temperatures?

SiC offers improved performance and reliability in high temperature environments, making it suitable for applications such as power electronics, aerospace, and automotive systems. It also has a longer lifespan and requires less maintenance compared to other materials.

5. How is the reliability of SiC at high temperatures tested?

Reliability testing for SiC at high temperatures includes thermal cycling, high temperature storage, and accelerated aging tests to evaluate its performance under extreme conditions. These tests help identify potential failure modes and ensure the material is suitable for long-term use.

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