How do you calculate contact resistance?
Contact Resistance
- Contact Resistance.
- The contact resistance is usually not well defined.
- R T = 2 R C + R sheet L W , ( Rsemi = R sheet L W )
- Contact Resistivity.
- Current Crowding.
- L T = ρ C R sheet.
- A typical arrangement for a TLM test pattern is shown below.
What is contact resistance of metal?
Contact resistance is a measure of the ease with which current can flow across a metal- semiconductor interface. In an ohmic interface, the total current density J entering the interface is a function of the difference in the equilibrium Fermi levels on the two sides.
What is ohmic contact resistance?
The Ohmic contact is a low resistance junction (non-rectifying) provides current conduction from metal to semiconductor and vice versa. Theoretically speaking the current should increase/ decrease linearly with the applied voltage.
What are ohmic contacts used for?
Low resistance ohmic contacts are used to allow charge to flow easily in both directions between the two conductors, without blocking due to rectification or excess power dissipation due to voltage thresholds. By contrast, a junction or contact that does not demonstrate a linear I-V curve is called non-ohmic.
What is 4 wire resistance measurement?
One solution is called the Kelvin, or 4-wire, resistance measurement method. It involves the use of an ammeter and voltmeter, determining specimen resistance by Ohm’s Law calculation. A current is passed through the unknown resistance and measured.
Is low contact resistance good?
We generally recommend trying to get less than 5,000 ohms for contact resistance—though we often recommend trying to get less than 1,800 ohms if possible.
What is the difference between Schottky contact and ohmic contact?
Schottky Contacts make good diodes, and can even be used to make a kind of transistor, but for getting signals into and out of a semiconductor device, we generally want a contact that is Ohmic. Ohmic contacts conduct the same for both polarities.
What is the difference between ohmic contact and rectifying contact?
A contact between metal and silicon can be rectifying or ohmic. The most commonly used rectifying contact is the Schottky barrier diode (SBD). A contact is said to be ohmic, i.e., non-rectifying, if it exhibits negligible resistance to current in both voltage polarities.
What are the possible types of metal contacts?
Basically, there are two types of MS contacts that are widely used in semiconductor devices:
- Rectifying Schottky Diodes.
- Non-rectifying Ohmic contact.
What is Schottky and ohmic contact?
Schottky Contacts make good diodes, and can even be used to make a kind of transistor, but for getting signals into and out of a semiconductor device, we generally want a contact that is Ohmic. Ohmic contacts conduct the same for both polarities. (They obey Ohm’s Law).
Why do we use 4 terminal resistors?
Why 4 terminal resistors are used? Explanation: Four terminals in resistance are used for overcoming parasitic resistances.