Every software package contains a full set of examples suitable for that version and are installed with the software. If you see examples here that are not in your installation you should consider updating to a later version of the software. These examples can be used by beginners and advanced users for product evaluation, teaching purposes, and self-training.

Required Modules

Victory Device:

• 2D Simulator

The example shows :
How to create a simple SONOS structure.

How to activate and specify the parameters for the SONOS model.

How to charge a SONOS structure.

How to obtain I-V curves at different charge states.

The first part of the deck sets up an N-channel MOSFET structure with a Silicon Nitride region in the gate insulator stack.

The MATERIAL statements change the gate insulators to be wide bandgap semiconductors in order to solve the drift-diffusion equation. The parameters such as mobility and densities of states are also set there.

The NITRIDECHARGE statement sets up the trap type and density in the Nitride layer as well as electron and hole capture cross-sections, and the re-emission time constant.

The PROBE statement, with the parameter SONOS.CHARGE causes the charged Nitride trap density (in this case integrated over the whole region) to be written to a log file.

On the MODELS statement the SONOS.EL flag enables tunnelling of electrons through the oxide layers, from the channel to the Nitride and from the Nitride to the Gate. QTNL.DERIVS helps with convergence of the non-local tunnelling model that is used.

A steady state bias is then applied to the drain, although this is not necessary to charge the Nitride layer. The Nitride is then charged by ramping up the gate bias in a transient simulation, continuing up to 10 s. The parameter SONOS.CURRS on the LOG statement causes the tunnel current both into and out from the Nitride layer to be saved in the Log File. A structure file is saved for selection of simulation times.

In the next section, the simulator is run without the SONOS model or the NITRIDECHARGE statement. The saved files from the transient run are read in. They contain the charge in the Nitride later, which is fixed for the simulation. The I-V characteristics are obtained, which show the progressive shift in threshold voltage.

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