New solver option
In the initial versions of the software, the Gummel’s method was used in the solver, in which the voltage and charge were solved sequentially (one was used as a input to the other) until the two were consistent. In DEVICE 1.5, the Newton solver has been introduced, which solves for the charge and voltage simultaneously. The Newton solver is more sensitive to the initial conditions (it may not converge), but will converge much faster for a wider variety of problems if it’s given a good initial guess.
Advanced contact models
Several modifications have been made to the contact models for DEVICE:
- Lumped element loads (R and C) can now be added on device terminals.
- Custom specification of DC sweep bias voltages is available.
- Non-ohmic contacts will use a Schottky barrier model accounting for barrier lowering due to the applied electric field.
Adaptive transient simulation
Transient simulations now employ adaptive time-stepping to optimally vary the simulation interval while maintaining accuracy. Coupled with the full Newton solver, a wider variety of transient simulations can now be performed efficiently with DEVICE. To view the new settings associated with the transient simulation, consult the "Transient" tab in the Device region properties. Here, the user may specify time step constraints, down-sampling, and shuttering for optical generation objects.
In the Device region properties, users now how the option to retain a reduced set of spatial data. Under the "Results" tab, a list of all available results can be viewed, and may be toggled on or off to reduce memory requirements. By default all results are included.