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
- 3D Diffusion & Implantation
Victory Mesh
- 3D Meshing
Victory Device
- 3D Simulator
- 3D REM
This example demonstrates Inter Device Leakage from XRay Total Dose Exposure.
For older technologies, one of the main effects of Total Dose Irradiation was the accumulation of positive charge in the gate oxide, resulting in threshold voltage shifts that either reduced current drive or increased off state leakage, depending on whether the device was a p- or n-MOS device respectively. For more aggressive technologies, the gate oxides are so thin, that the major effect of Total Dose Irradiation is the trapping of positive charge in the trench isolation oxides, creating a parasitic current leakage path between trench isolated devices. The leakage path could be between the Source/Drain contacts of two separate nMOS devices, or could be between the Source/Drain contact of an nMOS device and the n-Well isolation of a p-MOS device. In this example, we demonstrate the creation of a current leakage path between two nMOS devices. Leakage between an nMOS and pMOS n-Well is essentially the same phenomenon.
Victory Process is used to create the two nMOS devices, separated and electrically isolated by a trench and p-well with associated trench implants.
There are several basic input file set up requirements for simulating total dose effects in Victory Device:
The effected insulators must be simulated as wide bandgap semiconductors
Any doping in the insulator therefore needs to be removed
Insulator trap densities, characteristics and locations need to be defined
The radiation source and dose rate needs to be defined
The parameter “radiation ” needs to be invoked on the solve statement
To convert an insulator to a wide bandgap semiconductor, the material statement is used. For example: Material material=oxide semiconductor
To remove any existing doping from the insulator, which would cause erroneous conduction, the “doping replace ” syntax is used. For example: doping material=oxide replace uniform net concentration=-1
Two types of insulator traps can be defined, bulk insulator traps, using the oxidecharging statement and interface insulator traps, using the intoxidecharging statement in a direct analogy to defect and intdefect statements. Two model implementations are also available, the “Jmodel ” and the “Vmodel “. The user is directed to the manual to gain a full understanding of the meaning of all the parameters in these statements and the model implementation, as a full description is too lengthy for this brief example description.
The radiation source and dose rate are defined in the radiation statement. Here a 10keV XRay source and a dose rate of 1 Rad per second is defined, using the radiation statement: radiation doserate=1 XRay
The convenience of defining a dose rate of 1 Rad per second is that the total dose will be the same as the elapsed transient time in the solve statement, if the parameter “radiation ” was invoked in the transient from the start.
The simulation shows how the leakage between the two trench isolated nMOS devices, increases after a total dose of 3 MRads.
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