How to define orientation of Si in the device simulation?

I am trying to calculate capacitance of the MOS capacitor identical to one shown in this example:
In my case I have a specific orientation of Si wafer though (111). How can I specify this my simulation? If I disable all the valleys and leave only one valley, would this be identical to defining a specific crystal orientation?
If several valleys are enabled in simulation, how is it handled by software?

Hi @sokhoyan, you can create a new semiconductor material for your silicon and set the values of bandgap, effective mass, carrier mobility for your specific crystal orientation. It should be sufficient to define only one valley (the one with the smallest bandgap).

For semiconductor materials with multiple valleys, the solver always uses the valley that has the smallest bandgap.