In addition to the tutorial model in the last section of the Introduction to the Semiconductor Module book (Tutorial Model: DC Characteristics of a MOSFET), there are many examples in the Application Libraries. Every example is accompanied by a PDF documentation with step-by-step instructions and useful comments. The examples can be accessed either online (https://www.comsol.com/models/semiconductor-module) or within the software by going to the File Menu>Application Libraries>Semiconductor Module.

For users interested in the drift-diffusion type of formulations, we recommend to start with the simple model of a p-n junction with user-defined generation for a silicon solar cell: https://www.comsol.com/model/si-solar-cell-1d-35661. This gives a quick introduction to building a semiconductor model from scratch.

Next, the 1D heterojunction model demonstrates standard techniques to achieve convergence (see comments in the accompanying PDF documentation):  https://www.comsol.com/model/heterojunction-1d-14617.

To model the oxide domain explicitly, use the Charge Conservation domain condition, as shown in this example of an EEPROM:  https://www.comsol.com/model/programming-of-a-floating-gate-eeprom-device-18075.

3D models require swept mesh:  https://www.comsol.com/model/3d-analysis-of-a-bipolar-transistor-19699.