Metal Semiconductor contact (Part 2)

In summary, the quick changes in voltage and high frequency signals in Figures b) and c) cause a redistribution of charge and a change in the depletion region in the bulk semiconductor and the potential of the metal.
  • #1
Robotduck
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TL;DR Summary
Metal Semiconductor contact
MOS (p type)

1) Figure a) and b) are the cases of strong inversion. Figure b)-For high frequency signals, electrons at the semiconductor oxide interface do not get enough time to change ( I follow that ), but how come the charge in the bulk close to the depletion region changes with these high frequency signals and causes the change in the depletion region in the bulk ( which is bothering me )?
2)In Figure c) if we change the voltage ( ranging from accumulation to strong inversion )quickly, then the system does not have enough time for strong inversion but again - how come the charge in the bulk is responding with this change ?
3) How come the charge in the Metal is responding to these changes in figure b) and c) ? This also has the electrons as a majority carriers ?

Thank you in advance for taking time to answer these questions !
 

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  • #2
1) In Figure b), the high frequency signals cause the electrons at the semiconductor oxide interface to move quickly between the oxide and the bulk semiconductor. This movement of electrons causes a redistribution of charge in the bulk, leading to a change in the depletion region. 2) In Figure c), when the voltage changes quickly from accumulation to strong inversion, the electrons in the bulk are not able to move quickly enough to reach the inversion layer. The charge that is already present in the bulk does not have time to be redistributed, and so the depletion region in the bulk remains unchanged. 3) The metal is responding to these changes because it is in contact with the semiconductor, and the electrons in the metal can be attracted to the semiconductor when the voltage changes. This causes a redistribution of charge in the metal, leading to a change in the potential of the metal.
 

Related to Metal Semiconductor contact (Part 2)

1. What is the Schottky barrier height in metal semiconductor contacts?

The Schottky barrier height is the energy difference between the Fermi level of the metal and the conduction band minimum of the semiconductor. It is typically in the range of 0.2-1.2 eV for most metal-semiconductor combinations.

2. How does the Schottky barrier height affect the performance of metal semiconductor contacts?

The Schottky barrier height has a significant impact on the electrical properties of metal semiconductor contacts. It determines the barrier height for charge carriers to move from the metal into the semiconductor, affecting the contact resistance and current flow.

3. What is the difference between Ohmic and Schottky contacts?

Ohmic contacts have a negligible barrier height, allowing for easy flow of charge carriers between the metal and semiconductor. On the other hand, Schottky contacts have a significant barrier height, leading to non-ideal behavior and higher contact resistance.

4. How does the choice of metal affect the properties of metal semiconductor contacts?

The choice of metal can significantly impact the properties of metal semiconductor contacts. Different metals have different work functions and affinity for the semiconductor, leading to varying barrier heights and contact resistances. The choice of metal can also affect the stability and reliability of the contact.

5. What factors influence the formation of metal semiconductor contacts?

The formation of metal semiconductor contacts is influenced by various factors, including the choice of metal and semiconductor, surface preparation, and processing conditions. The crystal orientation and doping level of the semiconductor also play a role in the formation of the contact. Additionally, the presence of impurities or contaminants can affect the properties of the contact.

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