Temperature coefficient of resistance - size effects vs bulk

Click For Summary

Discussion Overview

The discussion centers on the effects of resistor size on the temperature coefficient of resistivity (alpha), particularly in the context of resistors that shrink to the nanoscale. Participants explore whether alpha, typically considered a material constant for bulk resistors, changes with dimensions such as cross-sectional area.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant seeks references on how resistor size affects alpha, questioning if it changes as dimensions approach tens of nanometers.
  • Some participants assert that alpha is a material constant that remains independent of dimensions.
  • Another participant references literature suggesting a different conclusion, indicating that alpha may depend on physical dimensions.
  • A participant notes that an article discusses resistivity in thin films and mentions surface roughness, interpreting this as a "virtual thickness" parameter rather than a change in bulk resistivity.
  • One participant speculates that differences in surface and grain effects on electron scattering could influence alpha based on size parameters like surface:volume ratio.
  • Another participant offers to share access to the referenced article, indicating a willingness to facilitate further discussion.

Areas of Agreement / Disagreement

Participants express differing views on whether alpha is affected by the dimensions of the resistor, with some asserting it is constant while others suggest potential dependence on size. The discussion remains unresolved.

Contextual Notes

Participants reference literature and theories, such as the Fuchs-Sondheimer theory, but there are limitations in accessing some sources and a lack of consensus on the interpretation of findings related to alpha and size effects.

Hyo X
Messages
101
Reaction score
11
I am looking for a reference to discuss the effects of resistor size on alpha, the temperature coefficient of resistivity.
If we use the linear R=R0*(1+alpha*(T-T0))
alpha is a material constant, presumably for bulk-type resistors. Will alpha change as size (cross sectional area) of the resistor shrinks to tens of nanometers in one dimension? any reference on this? thanks
 
Engineering news on Phys.org
Alpha is a material constant that is independent of the dimensions.
 
Baluncore said:
Alpha is a material constant that is independent of the dimensions.

I concluded something different, based on literature.

http://iopscience.iop.org/1347-4065/9/11/1326there is also the fuchs-sondheimer theory but i don't think it dicusses alpha
 
I cannot access that article because it is behind a pay-wall.

The abstract refers to resistivity as being determined by surface roughness in thin films. I would interpret that as a “virtual thickness” parameter, not as a change in the bulk material resistivity.

Although the abstract mentions the temp-co was also studied, it reveals no temp-co effect due to thickness. That might suggest that there was no significant effect on alpha observed.
 
I can't attest to the quality of the article but it has the suggestion that alpha may have some dependence on the physical dimensions of the sample.

I think a difference in the effect of surfaces and grains on the scattering of electrons and scattering or localization of phonons could conceivably contribute to changes in alpha as a function of surface:volume ratio or some other size parameter.

for completeness, from the article
Here h is the amplitude of oscilations describing the surface roughness and lambda is the mean-free-path of electrons.
Alpha-thickness.png

definition%20of%20h.png

if you are really interested in the article let me know and i can send you a dropbox link or something
 

Similar threads

Replies
5
Views
2K
Replies
5
Views
4K
Replies
6
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 34 ·
2
Replies
34
Views
6K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 4 ·
Replies
4
Views
5K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
1
Views
5K