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 Process
- 2D Diffusion & Implantation
Victory Device
- 2D Simulator
- 2D MixedMode
Total power loss comprises both a conductance power loss component and a capacitive loss component. As the cell pitch decreases, the conduction loss will decrease while the capacitive loss will increase. Therefore for small cell pitch the capacitive power loss may be the dominant component in the total power loss in the device. The need is now clear for a method that will allow analysis of the capacitive component of the power loss. One technique for doing this in a DMOS device is to analyse the gate charging time. This example illustrates a technique whereby the gate charging time for a vertical DMOS structure may be simulated, and the gate charge (Qg) required for switching the MOSFET can be determined.
The example contains the following parts:
-Process simulation to create the vertical DMOS
-The SPICE-like command syntax for simulating MixedMode circuits
-Steady state analysis that defines the DC operating point
-Time domain analysis that illustrates gate charging
The first section uses Victory Process to build a vertical DMOS power device and the CONFORMALSTR on the SAVE statement stores a structure file with conformal mesh. It is passed to Victory Device for electrical analysis using the MixedMode module. In the MixedMode simulation, a steady-state simulation followed by a transient gate charging simulation of the power circuit is performed.
The .BEGIN and .END statements indicate the beginning and end of the MixedMode syntax. The MixedMode commands are similar to those used in SmartSpice. Circuit components, topology, and analysis are defined within these statements. In general, the circuit component definition consists of three parts: the type of component, the lead or terminal node assignments, and the component value or model name.
For example, the first component definition in this simulation is an independent current source defined by IIN between the circuit nodes 0 and GG. The following value of 0 indicates that the initial current source value is 0 Amps, and PULSE defines a long current pulse of constant value for the transient gate charging analysis. The remaining circuit components are a resistor RG, another independent current source IOUT, a compact diode model DOUT and a voltage source VDD.
The AMOS statement specifies a device to be analysed by Victory Device. The A part of the AMOS command specifies that this is a TCAD device statement. The MOS portion simply defines the device name. The option INFILE= indicates which device structure file is to be used. The .NODESET statement defines the initial values for node voltages. The .DC statement indicates that a DC ramp is applied to the source IOUT . Additionally, the .OPTIONS command specifies the numerical method used in the simulation. The .TRAN statement is used to specify the initial time step and total duration of the transient analysis, which starts after all the .DC statements. In addition, the .LOG statement saves all the steady-state and transient simulation results over the bias or time interval specified. The .SAVE statement saves the final solution to the indicated file, once all the MixedMode analysis is completed. Other command line options exist. Please refer to the MixedMode section of the Victory Device or Victory Device user’s manual for a complete list.
To completely specify the simulation, the physical models used by Victory Device must be specified. The MODELS statement is used to turn on the appropriate transport models. This set includes: CVT – mobility model for MOSFETs, SRH – Shockley-Read-Hall recombination, AUGER – recombination accounting for high level injection effects, and BGN – band gap narrowing. Refer to the user’s manual for a description of these models. Finally, the IMPACT statement enables the Selberherr impact ionization model.
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