Depletion region vs Film thickness

In summary, the conversation discusses the question of what happens when the predicted depletion region of a diode is larger than its actual thickness. The person mentions that some papers assume that this affects the built-in potential, but this seems questionable as textbook solutions are based on the assumption of a quasi-neutral region. The conversation ends with a request for help in understanding this concept.
  • #1
yehokhenan
7
0
Here's something I can't get my head around:

Take a diode (can be schottky, p-n etc) where the predicted depletion region is larger than the actual thickness of that layer will ever be. What happens?

I've seen papers where its assumed that this curtails the built in potential. But it sounds fishy, namely because the all the textbook solutions are based on the assumption that there's a quasi-neutral region beside the depletion region and this gives you the boundary conditions you need to solve for depletion widths. The laws that always hold true, as far as I understand, are that the built-in potential equals the difference in Fermi levels and the vacuum level is continuous...so you should always get the same built-in potential across two layers? Regardless of their thickness?
 
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  • #2
I'm not sure what to make of this. I can't find anything on this either so any help would be much appreciated!
 

FAQ: Depletion region vs Film thickness

1. What is the depletion region and how does it affect film thickness?

The depletion region is a region near the interface of a semiconductor material where the concentration of free charge carriers is significantly reduced, creating a depletion of charge carriers. This can affect the film thickness as it may result in a decrease in conductivity and an increase in resistance within the film.

2. What factors influence the size of the depletion region?

The size of the depletion region is influenced by the type and concentration of dopants in the semiconductor material, as well as the applied voltage or electric field. The type and thickness of the film can also affect the size of the depletion region.

3. How does the thickness of a film affect the size of the depletion region?

The thickness of a film can directly affect the size of the depletion region. A thicker film may have a larger depletion region due to the increased distance between the electrodes, leading to a higher potential barrier and a larger depletion of charge carriers.

4. What is the relationship between film thickness and depletion region width?

The relationship between film thickness and depletion region width is dependent on the type of semiconductor material and the applied voltage. In general, as the film thickness increases, the depletion region width also increases. However, this relationship may not hold true for all materials and conditions.

5. How does the depletion region affect the performance of semiconductor devices?

The presence of a depletion region can have both positive and negative effects on the performance of semiconductor devices. On one hand, it can improve the efficiency of certain devices by reducing leakage currents and improving charge carrier transport. On the other hand, it can also lead to unwanted voltage drops and limitations in device functionality.

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