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

Subthreshold ideality factor

Optional number. Subthreshold swing ideality factor between 1 and 2.

Temperature (K)

Optional number in K. Absolute device temperature.

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

Compute the weak-inversion MOSFET transconductance efficiency gm/ID = 1/(n kT/q) from ideality factor and absolute temperature. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

GM/ID efficiency (V^-1)

Returned number in V^-1. Transconductance efficiency gm/ID per volt of ID.

• Material composition, geometry, process history, temperature, electric field, bias, interfaces, parasitics, and fitted parameter ranges can invalidate a compact semiconductor model.
• Subthreshold ideality factor must be at least 1.
• Subthreshold ideality factor must be no greater than 2.
• Temperature 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.

• Subthreshold Swing Calculator

  Compute MOSFET subthreshold swing from absolute temperature and the depletion-to-oxide capacitance ratio using S = ln(10) kT/q (1 + Cdep/Cox).

• BJT Common-Base Current Gain Calculator

  Compute the BJT common-base current gain alpha as the product of emitter efficiency and base transport factor.

• Diode Ideality Factor Calculator

  Extract the diode ideality factor n from two forward-bias points on the exponential Shockley relation. Formula: n = (V2 - V1) / (Vt·ln(I2/I1)), where thermal voltage Vt = k·T/q (k=1.380649e-23 J/K, q=1.602176634e-19 C). Inputs: I1>0 mA, I2>0 mA and I1≠I2, V1 and V2 finite V, T>0 K (default 300 K). Output: n>0 (physical diode typically 1 ≤ n ≤ 2; n=1 ideal diffusion, n≈2 recombination/generation; n outside 1-2 indicates series resistance, high injection, or measurement error). Assumes forward exponential region, negligible series resistance, and constant temperature.