Bulk n-type Silicon

mcdeviceex01.in : Bulk n-type Silicon

Requires: MC Device
Minimum Versions: Atlas 5.22.1.R

This example demonstrates the simulation of electron transport in bulk n-type silicon with a single value of the doping and the electric field.

This example shows how to set bulk material properties, the number of iterations, the MC time step, and the number of carriers (i.e., electrons). This example also shows how to obtain estimates of the bulk mobility. This example introduces the bulk mode of MCDEVICE and basic concepts of modeling charge transport in bulk semiconductors.

The bulk material properties are set on the BULK statement. The FIELD parameter and the DOPING parameter are the most commonly used. In this case, a low field with no doping is chosen to model the behavior of mobile electrons in intrinsic silicon in the linear region of the velocity-field characteristic.

The number of iterations and duration of the time step are set on the ALGO statement. The ITER parameter implies that mobility estimates in the mcdeviceex1_diff.log file are averaged over of TIME = ( ITER - TRANS ) * DT = (10000-0)*(1e-15 s) = 10e-12 s = 10 ps. To improve the estimates, increase TRANS , which is the number of transient iterations performed before TIME=0 when MCDEVICE begins to collect data for the averages. The number of computational carriers used in the Monte Carlo model is determined by the N parameter on the PARTICLE statement. For bulk simulations, N represents the ensemble size used to collect data. The magnitude of the noise of the averages will be reduced both by increasing the size of the ensemble and by increasing the time during which data is collected, namely ( ITER - TRANS ) * DT ).

The mobility estimates along with other time-averaged quantities are written into the mcdeviceex01_diff.log file. You can plot these with TonyPlot. The best estimate for the mobililty is obtained when drift-derived and diffusion-derived estimates converge.

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.