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

Critical field (MV/cm)

Required number in MV/cm. Critical electric field the junction sustains at breakdown. Must be greater than 0 MV/cm.

Depletion width (um)

Required number in um. Depletion width at breakdown. Must be greater than 0 µm.

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

Estimate one-sided abrupt-junction avalanche breakdown voltage from the peak critical field and depletion width: Vb ≈ Ecrit·W/2. The factor 50 converts MV/cm·µm to volts and includes the triangular-field factor of one half. The estimate neglects curvature, edge termination, and the full ionization integral. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

Breakdown voltage (V)

Returned number in V. Avalanche breakdown voltage (magnitude). At least 0 V.

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

• BJT Base Width Modulation Calculator

  Quantify BJT base-width modulation (Early effect) from the reverse-biased collector-base junction: fractionalChange = (sqrt(Vbi+VCB)-sqrt(Vbi))·sqrt(2·εSi/(q·NA)) / Wb, with Vbi=builtInVoltageV>0 V, VCB=collectorBaseVoltageV>=0 V, NA=acceptorDopingPerCm3>0 cm^-3, Wb=baseWidthUm>0 um, εSi=11.7·ε0 F/cm, q=1.602e-19 C. Uses stable sqrt difference; checks total voltage finiteness and depletion-factor overflow. One-sided abrupt-junction approximation neglecting emitter side and non-uniform doping; valid for NA not too low and moderate VCB; result >=0, zero when VCB=0.

• One-Sided Abrupt Junction Depletion Capacitance Calculator

  Compute one-sided abrupt silicon junction depletion capacitance from area and lightly doped-side concentration. Assumes εSi = 11.7·ε0.

• APD Multiplication Factor Calculator

  Compute the avalanche photodiode multiplication factor from the Miller model M=1/[1-(V/Vb)^N]. Inputs are magnitudes: reverse-bias magnitude V≥0 V must remain below breakdown magnitude Vb>0 V (numerator V, denominator Vb; V=0 gives M=1, V→Vb- diverges). Exponent N in [1, 6] (default 2) captures the ionization coefficients. Signed voltages are not supported (use magnitudes). Result M≥1 is a dimensionless factor (per-carrier gain, not total current).