Metal-Semiconductor Schottky Barrier

SamanthaSamantha Member Posts: 2

Hello,

I am simulating an Al-Ge-Cu asymmetric MSM photodetector which has two Schottky junctions. My questions are:

  1. In Lumerical CHARGE solver, how barrier height is determined at the metal-semiconductor Schottky junctions ?
  2. Does the solver takes into account the Fermi level pinning effect? For example, I found in papers that Ge-metal Schottky junctions are severely affected by Fermi level pinning effect and Schottky barrier height in metal/Ge contacts shows weak dependence on the metal work function [A]. Does the solver physics takes care of this?
  3. If answer to Qs 2 is 'no', how I may incorporate the Fermi level pinning effect in my model?
  4. Lastly, in the CHARGE solver, the default work function of Ge is 4.5 eV. Can you provide any reference/explanation of how this number is used? If I use moderate doping level of ~10^16 cm-3, can 4.5eV of workfunction be used for Ge in my model?

Thank you.


[A] APPLIED PHYSICS LETTERS 89, 252110 (2006)

Answers

  • kghaffarikghaffari Posts: 80Ansys Employee

    Hi,

    Thanks for reaching out. For Schottky junctions the barrier height is determined by the difference in metal and semiconductor work function. As far as I know pinning effect is not considered for Schottky junctions in CHARGE. You might be able to mimic the intended behavior by manually changing the carrier density at the interface. If you could you please describe the effect you hope to see (e.g. for band structure) I can further comment. For germanium I see this work reports the same value for work function. When applying doping you don’t have to update the value for work function.

    Best regards

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