Use this semiconductor calculation for first-order device, material, fabrication, interconnect, packaging, or reliability estimates when every coefficient and unit convention is known.

Channel length (nm)

Required number in nm. Effective electrical channel length.

Characteristic length (nm)

Required number in nm. Characteristic decay length of the barrier lowering.

Prethreshold current (nA)

Required number in nA. Prethreshold current driving the punch-through path.

The cited overview of MOSFET supplies background for the terminology and domain context used by this tool.^[1]

Estimate subthreshold punch-through current from the prethreshold current and channel length decay. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

Punch-through current (nA)

Returned number in nA. Punch-through leakage current.

• Material composition, geometry, process history, temperature, electric field, bias, interfaces, parasitics, and fitted parameter ranges can invalidate a compact semiconductor model.
• Channel length must be at least 5e-324.
• Characteristic length must be at least 5e-324.
• Prethreshold current must be at least 0.
• Use finite inputs in the displayed units, preserve source measurements and assumptions, and independently verify consequential decisions.

Compare the estimate with measured process data, current device documentation, and a higher-fidelity circuit, field, thermal, quantum, or TCAD model when the decision requires it.

• Band-to-Band Tunneling Calculator

  Estimate band-to-band tunneling current from the junction field through a field-driven exponential: I[nA]=coeff·E·exp(-E0/E) with E=electricFieldMVPerCm>0 MV/cm, E0=characteristicFieldMVPerCm>0 MV/cm, coeff=tunnelingCoefficient>=0 nA/(MV/cm). Defaults E0=40 MV/cm, coeff=1 nA/(MV/cm). Simplified Kane-like model; neglects barrier shape, temperature, and trap-assisted contributions; valid only for E comparable to E0 and for the fitted material.

• BJT Punch-Through Voltage Calculator

  Compute the total collector-base junction potential required for the depletion region to span a uniformly doped neutral base: Vtotal=q·NB·WB²/(2·εSi). This is not the externally applied reverse bias; subtract the junction built-in potential to estimate that bias.

• Threshold Voltage Roll-Off Calculator

  Estimate the negative threshold-voltage shift caused by short-channel roll-off relative to the minimum channel length.