Transfer Length Calculator
Convert specific contact resistivity and sheet resistance into the contact transfer length. Formula: Lt [µm] = 1e4 · sqrt(ρc [Ω·cm²] / Rsh [Ω/sq]). Inputs: ρc > 0 Ω·cm², Rsh > 0 Ω/sq. Output: Lt > 0 µm. Assumes uniform sheet resistance under the contact and the transmission-line model (long contact, negligible metal resistance).
Description
Calculate transmission-line-model contact transfer length from specific contact resistivity and sheet resistance.
Convert specific contact resistivity and sheet resistance into the contact transfer length. Formula: Lt [µm] = 1e4 · sqrt(ρc [Ω·cm²] / Rsh [Ω/sq]). Inputs: ρc > 0 Ω·cm², Rsh > 0 Ω/sq. Output: Lt > 0 µm. Assumes uniform sheet resistance under the contact and the transmission-line model (long contact, negligible metal resistance).
When to use Transfer Length Calculator
- Calculate transmission-line-model contact transfer length from specific contact resistivity and sheet resistance.
- Compare fabrication or device scenarios while holding coefficients and unit conventions constant.
- Check a hand calculation before moving to a higher-fidelity process, circuit, or TCAD model.
How the calculation works
Current crowding makes contacts much longer than LT provide diminishing resistance improvement; LT is a length, not contact resistance.
LT = √(ρc/Rsh) Interpreting the result
Current crowding makes contacts much longer than LT provide diminishing resistance improvement; LT is a length, not contact resistance.
Assumptions and limitations
- Uniform sheet resistance under the contact, negligible metal resistance, and the one-dimensional transmission-line model are assumed.
- Use parameters measured for the same material, geometry, temperature, and operating regime whenever the result informs engineering work.