CapeSym

Table of Contents

Recording Run Values

Temperature results of every run are written to a file for later examination from the Results menu or with a spreadsheet. By default, only the minimum and maximum temperature of the device are recorded, but the temperature extremes of any components may be selected for recording, along with the values of any parameters by checking the Record check box at the bottom of the associated dialog. Recording a component will record both temperature and material. Recording a parameter will record the value of the parameter.

ALL parameter values along with temperature extremes and material names for ALL components are recorded whenever the Record everything box is checked in the Run Value Recording dialog. This dialog is accessed from the Solve menu, through the Configure Run submenu, by the Value recording... menu item. Selections to record individual parameters and components have no effect when Record everything is selected. In addition, starting with version 2.8.1 average component temperatures will be included with the minimum and maximum whenever the Include average component temperatures option is selected. This option is equivalent to having recordAverageTemps = “true” in the XML file (Simulation section, Record attribute), which will enable background runs using xSYMMIC to save average component temperatures as well.

Run values are written in comma separated values ASCII format. This format is readable by most spreadsheets such as Microsoft Excel, OpenOffice Calc, and Google Docs. After each simulation run, a line of comma separated values is appended to the current recording file. Before the first data line is written, or whenever there is a change in the number of items being recorded, a header line is written to describe the fields. The first four fields recorded are always Device, Time, Tmin and Tmax, where Device is the number and title of the device, and Tmin and Tmax are the temperature extremes of the device at the time point given by Time.

Each parameter is recorded as a single field, headed by the parameter name, with the associated parameter value on each subsequent data line. Each component recording is made up of three fields. In the heading is the name of the component followed by “Tmin” and “Tmax” (and “Tavg” if the average option is selected). In the data lines these fields contain the material of the component and the minimum and maximum(and volume-average) temperatures on the component. The following example shows the output for recording the parameter Number of Gates along with the component Sources (which is made of Ohmic material). Sources include all the source contact metal in the device.

For steady-state solutions the time field is written as Inf (Infinity). For solutions through time, the time field is the time (in seconds) for which the temperature solution was calculated. A recording is made for each time point that is saved in the solution file.

Note: Run value temperatures are always recorded in kelvin, rather than with respect to the current temperature scale. This ensures that values recorded after runs from different sessions are always consistent.

By default, the recording of run values is to a file named the same as the device template filename with a .csv extension. So, for a template called “FET.xml”, run values would be recorded to “FET.csv”. When a multi-device layout is run, a default .csv file will be written for each device in the layout. If the devices in the layout all come from a single device template, the run values for each device will be written sequentially to this device's .csv file. To avoid confusion with run values written for single device simulations, it may be desirable to designate a separate recording file for layout results. This can be done through the Run Value Recording dialog, as shown in the figure.

Recording files are normally given a .csv file extension, but this is not strictly required. The .csv extension is usually recognized by most spreadsheet software. After a new file is chosen for recording run values, all subsequent simulation runs will be recorded to this file until a template is opened or a layout is changed. The name of the recording file associated with a device will be saved to the template when the device is saved. For a layout, the recording filename will be saved into every device template file in the layout.

Note: Run values are always appended to the designated recording file, such that data is never overwritten. Selecting a previously used file for recording will result in new simulation runs being ADDED to the file rather than overwriting the existing data in it.

The content of the run values recording file can be examined through the Recorded values... command from the Results menu. This dialog opens the recording file specified in the Value Recording dialog, or if none was specified, the default recording file for the first device in the layout. See the Examining Results section for more details.