Boundary Conditions#
A boundary condition pairs a condition (the physical constraint, e.g. an
applied voltage) with a placement (where on the geometry it is applied) via a
HeatChargeBoundarySpec. Collect these in
HeatChargeSimulation.boundary_spec.
Note
A charge simulation requires at least two VoltageBC boundaries. When a
SteadyCapacitanceMonitor is present, one of the voltage sources must sweep
an array of voltages (len(voltage) > 1) so the capacitance can be
computed from the DC sweep.
Specifications#
Heat BC specification. |
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Heat-Charge boundary conditions specification. |
Types#
The condition applied at the boundary. VoltageBC and CurrentBC draw
their excitation from the SPICE source classes documented on the
SPICE 🔌 page.
Constant electric potential (voltage) \(= \text{V}\) boundary condition. |
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Current boundary conditions. |
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Insulation boundary condition. |
Note
Schottky contacts are opt-in on VoltageBC via
model="schottky_mott". The Schottky-Mott barrier
\(\phi_{Bn} = W - \chi\), \(\phi_{Bp} = E_g - \phi_{Bn}\) is
built from per-medium material properties: work_function on the
adjacent ChargeConductorMedium, and electron_affinity,
richardson_electron, richardson_hole on the adjacent
SemiconductorMedium. The default model="ohmic" is
the standard ohmic contact. Schottky contacts are supported only by
the accelerated charge solver (use_accelerated_solver=True) and
compose with DC sweeps, small-signal AC analyses, and Fermi-Dirac
carrier statistics (fermi_dirac=True).
Placement#
Where a condition is applied: on an interface between structures or mediums, on a structure’s outer boundary, or on the simulation domain boundary.
Placement of boundary conditions between two structures. |
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Placement of boundary conditions on the structure's boundary. |
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Placement of boundary conditions between two mediums. |
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Placement of boundary conditions on the simulation box boundary covered by the structure. |
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Placement of boundary conditions on the simulation box boundary. |