FD-SOI SET

In this section, we demonstrate how QTCAD can be used to model a realistic single-electron transistor (SET) based on a fully-depleted silicon-on-insulator (FD-SOI) platform. This practical application contains five Python scripts: three numbered scripts to be run in sequence, plus two auxiliary scripts containing functions and constants that are imported throughout the workflow. In the first part of this section, we use QTCAD Builder to construct a mesh for the FD-SOI device. In the second part, we solve the linear Poisson equation throughout the entire device to obtain the electrostatic potential profile for a given set of gate voltages. In the third part, we compute the chemical potential of the quantum dot region as a function of the SET gate voltage, thereby identifying the Coulomb peaks and estimating the SET charging energy.

• 1. Mesh generation using QTCAD Builder
• 2. Creating the FD-SOI device
• 3. Simulating electrostatics using the linear Poisson solver
• 4. Computing the chemical potential of an SET device
• 5. Simulating the Coulomb peak positions of an SET

Note

This practical application (in particular Simulating the Coulomb peak positions of an SET) relies on converging Schrödinger–Poisson calculations with a relatively large number of electrons (around 12) with high level of precision (tol=1e-5). As a result, these simulations are more computationally demanding than those in other tutorials and practical examples. For reference, running Simulating the Coulomb peak positions of an SET on workstation described as “System 2” in Hardware requirements takes approximately 1.5 hours.