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

SmartSpice

Here we use an internal SmartSpice algorithm to calculate the total track charge created by the strike which is then converted into current time pairs internally at a specified device node and time.

The obvious advantage of using Spice to calculate the SEU track charge versus time, instead of using TCAD, is simulation speed. The downside is that the calculation is a worst-case calculation, since it is assumed that all the generated charge is collected by the device node, which is not usually the case. Indeed, the actual fraction of charge collected depends on strike angle and strike location and whether any carrier multiplication occurs from high electric fields and internal gain etc.

The SEU event is struck at the nMOS drain node. The example specifies a Linear Energy Transfer value of unity, which is set using the .PARAM DLET=1 statement. The total charge in the charge track is calculated by integrating over the SEU track length, which is set by the .PARAM F_LENGTH=0.5u statement. Other timing parameters are also set on .PARAM statement lines.

For simulation method comparisons, the SRAM operation point is set to its low power configuration with an applied supply voltage of 0.85 volts, which represents the state of highest sensitivity to being upset by a single event.

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