Overview and Structure Definition

optoex01.in : Overview and Structure Definition

Requires: S-Pisces
Minimum Versions: Atlas 5.22.1.R

The following set of examples demonstrates how to extract device characteristics for general photodetectors. These characteristics are of interest to those involved in the design of PN and PIN photodiodes, avalanche photodiodes, photoconductors, phototransistors, optical FETs and MSMs. These examples focus principally on optoelectronic characteristics as opposed to the purely electronic behavior of photodetectors (e.g. dark current, capacitance).

The following examples will address a PIN photodetector. The extraction techniques used on the PIN device will equally apply to other photodetector devices. The device for these examples is described in the input file "optoex01.in". This input file should be run before any of the other examples in this section as it provides the base device structure used in the other examples.

The first section of the input file specifies the mesh. In this case, the mesh is 10 microns by 10 microns. The spacings were chosen to help resolve the P+ N and N N+ junctions. The space.mult parameter is used to make the mesh coarse for fast simulation. For more accuracy, the value should be set to unity.

The second section of the input file specifies the structure of the device. The device is a square of silicon with an anode extending across the front surface (y=0.0) and a cathode across the bottom. It is uniformly doped N-type at 1.0e14, with heavily doped P+ and N+ regions at the front and back surfaces respectively.

The third section of the input file specifies which material models will be used in the simulation. Here SRH and Auger recombination mechanisms have been specified since they have important effects on the quantum efficiency of photodiodes. Concentration and field dependent mobility models are also specified.

The last section of the input file is used to obtain an initial solution. The initial solution is written to a solution file that is used in all the subsequent photodetector analysis examples. The output file can be viewed using TonyPlot. This shows the structure of the device and the device mesh.

To load and run this example, select the Load example button in DeckBuild. This will copy the input file and any support files to your current working directory. Select the run button to execute the example.