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

Area (cm^2)

Required number in cm^2. Junction cross-section area. Must be greater than 0 cm².

Built-in voltage (V)

Optional number in V. Built-in potential. May be 0 V only when reverse bias makes the combined junction potential positive.

Doping (cm^-3)

Required number in cm^-3. Lighter-side doping concentration. Must be greater than 0 cm^-3.

Reverse bias (V)

Optional number in V. Applied reverse bias. Must be at least 0 V, and its sum with built-in potential must be positive.

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

Compute one-sided abrupt silicon junction depletion capacitance from area and lightly doped-side concentration. Assumes εSi = 11.7·ε0. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

Capacitance (pF)

Returned number in pF. Ideal one-sided abrupt-junction depletion capacitance.

• Material composition, geometry, process history, temperature, electric field, bias, interfaces, parasitics, and fitted parameter ranges can invalidate a compact semiconductor model.
• Area must be at least 5e-324.
• Built-in voltage must be at least 0.
• Doping must be at least 5e-324.
• Reverse bias 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.

• 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.

• Depletion Capacitance Linearly Graded Junction Calculator

  Compute the depletion capacitance of a linearly graded silicon junction. Assumes silicon permittivity 11.7·ε0.

• Depletion Width Abrupt Junction Calculator

  Compute the total depletion width of an abrupt pn junction from built-in and applied reverse bias. Assumes silicon permittivity 11.7·ε0.