tidy3d.FossumCarrierLifetime

tidy3d.FossumCarrierLifetime#

class FossumCarrierLifetime[source]#

Bases: Tidy3dBaseModel

Doping- and temperature-dependent SRH carrier lifetime.

Parameters:

  • tau_300 (PositiveFloat) – [units = sec]. Carrier lifetime at 300K

  • alpha_T (float) – Exponent for thermal dependence

  • N0 (PositiveFloat) – [units = 1/cm^3]. Reference concentration

  • A (float) – Constant A

  • B (float) – Constant B

  • C (float) – Constant C

  • alpha (float) – Exponent constant

Notes

This model expresses the Shockley-Read-Hall carrier lifetime as a function of absolute temperature \(T\) and total ionized dopant concentration \(N = N_D + N_A\):

\[\tau(N, T) = \frac{\tau_{300}\,(T/300)^{\alpha_T}}{A + B\,(N/N_0) + C\,(N/N_0)^{\alpha}}\]

The model is physically meaningful only with \(A = 1\); a warning is emitted if any other value is provided. The \(B\,(N/N_0)\) term is the linear doping form introduced by Fossum [1], which alone gives \(\tau \propto 1/(1 + N/N_0)\). The \(C\,(N/N_0)^{\alpha}\) term adds a higher-order doping contribution; typical exponents are \(\alpha = 1\) (Fossum-shaped) or \(\alpha = 2\), which reproduces the Auger-like high-doping behaviour obtained by collapsing the SRH + Auger parallel combination of Roulston et al. [2] into a single denominator. The \((T/300)^{\alpha_T}\) factor is the empirical temperature scaling of Klaassen [3].

Example

>>> import tidy3d as td
>>> default_Si = td.FossumCarrierLifetime(
...   tau_300=3.3e-6,
...   alpha_T=-0.5,
...   N0=7.1e15,
...   A=1,
...   B=0,
...   C=1,
...   alpha=1
... )

References

Attributes

tau_300

alpha_T

N0

A

B

C

alpha

tau_300#
alpha_T#
N0#
A#
B#
C#
alpha#