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

I1 (mA)

Required number in mA. First forward current. Must be greater than 0 mA.

I2 (mA)

Required number in mA. Second forward current. Must be greater than 0 mA and distinct from I1.

V1 (V)

Required number in V. First forward voltage. Finite voltage in volts.

V2 (V)

Required number in V. Second forward voltage. Finite voltage in volts; (V2-V1) must have same sign as ln(I2/I1) for positive n.

Temperature (K)

Optional number in K. Device temperature. Must be greater than 0 K.

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

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. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

Ideality factor

Returned number. Extracted ideality factor. Greater than 0; physical range typically 1 to 2.

• Material composition, geometry, process history, temperature, electric field, bias, interfaces, parasitics, and fitted parameter ranges can invalidate a compact semiconductor model.
• I1 must be at least 5e-324.
• I2 must be at least 5e-324.
• Temperature must be at least 5e-324.
• 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.

• Diffusion Capacitance Calculator

  Compute the diffusion capacitance of a forward-biased diode from stored-charge lifetime and current. Formula: Cdiff [nF] = 1e9 · (τ [ns]·1e-9 · I [mA]·1e-3) / (n · Vt [V]), where Vt = k·T/q (k=1.380649e-23 J/K, q=1.602176634e-19 C). Equivalent: Cdiff [F] = τ·I/(n·Vt). Inputs: I ≥ 0 mA, τ > 0 ns, n ≥ 1 (default 1), T > 0 K (default 300 K). Output: Cdiff ≥ 0 nF. Assumes low-level injection, negligible depletion capacitance, and quasi-neutral stored charge τ·I.

• Semiconductor Effective Density Conduction Band Calculator

  Compute the conduction-band effective density of states from a density-of-states effective mass and temperature. Formula: Nc(T) = 2.51e19·(m*_dos/m0)^{3/2}·(T/300)^{3/2} [cm⁻³], where 2.51e19 cm⁻³ is the 300 K value for m*=m0, m*_dos>0 is the DOS effective mass ratio, T>0 K is lattice temperature (default 300 K). Inputs: m*_dos>0 (default 1), T>0 K (default 300 K). Output: Nc>0 cm⁻³. Assumes parabolic band, Boltzmann statistics, and isotropic effective mass.

• Diode Saturation Current Calculator

  Extract the positive Shockley saturation-current parameter from one forward-bias point using Is = I/[exp(V/(n·Vt))−1]. The logarithmic evaluation remains stable at high forward voltage. This parameter is not necessarily equal to a diode's measured reverse-leakage current.