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
- 2D Optical
This example demonstrates an Avalanche PhotoDiode (APD) where absorption and multiplication regions are separated. It also demonstrates the use of the Geiger mode to study its behavior as a single photon counter at biases beyond breakdown.
The APD should maximize photon absorption. However the multiplication region should be thin in order to minimize secondary ionizations. These two conflicting requirements are achieved in Separate Absorption Multiplication (SAM) reach Through APD.
Advanced III-V heterostructures can be used to detect different wavelengths of light such as infra-red and ultraviolet. These heterostructures are often combined with silicon layers which are used for carrier multiplication. A typical example is shown here.
Since the device is 1D we used the ômesh autoö feature of Victory Device to create the structure. When using auto-meshing, you must only specify the mesh in the X direction using X.MESH statements. The mesh spacing in the Y direction is specified in the REGION statements. The REGION statement is used as well to specify the material types of individual “regions “, their composition, doping, strain and certain other characteristics describing how the region is to be modelled.
The photogeneration rate is calculated using the beam statement. The beam was back illuminated for better gain in the linear region, a wavelength of 1um and a beam intensity of 0.1Watts/cm2 was used.
IV characteristics (dark as well under illumination) are simulated by ramping the anode voltage up to around -22V where the diode starts to breakdown and then beyond to -30V where the Geiger mode comes into play.
For the Geiger mode simulation, a probe statement was added so that the electron avalanche probabilities at the designated point versus bias could be seen on the log file.
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