Quantum device-simulation with the density-gradient model on unstructured grids

We describe an implementation of the density-gradient device equations which is simple and works in any dimension without imposing additional requirements on the mesh compared to classical simulations. It is therefore applicable to real-world device simulation with complex geometries. We use our implementation to determine the quantum mechanical effects for a MOS-diode, a MOSFET and a double-gated SOI MOSFET. The results are compared to those obtained by a 1D-Schrodinger-Poisson solver. We also investigate a simplified variant of the density-gradient term and show that, while it can reproduce terminal characteristics, it does not give the correct density distribution inside the device.