Engineering Si-Qubit MOSFETs: A Phase-Field Modeling Approach Integrating Quantum-Electrostatics at Cryogenic Temperatures

TL;DR

This paper develops a phase-field modeling approach to analyze Si-Qubit MOSFETs at cryogenic temperatures, integrating quantum mechanics and electrostatics to optimize device design and understand quantum dot coupling effects.

Contribution

It introduces a comprehensive phase-field modeling framework that couples quantum and electrostatic effects, validated against experimental data for Si-Qubit MOSFETs at cryogenic temperatures.

Findings

Interface traps influence quantum dot barrier heights and coupling.

Optimized gate and spacer dimensions improve control over quantum well depths.

Model accurately captures Coulomb blockade oscillations in experimental data.

Abstract

This study employs advanced phase-field modeling to investigate Si-based qubit MOSFETs, integrating electrostatics and quantum mechanical effects. We adopt a comprehensive modeling approach, utilizing full-wave treatment of the Schrodinger equation solutions, coupled with the Poisson equation at cryogenic temperatures. Our analysis explores the influence of interface traps on quantum dot (QD) barrier heights, affecting coupling due to tunneling. A wider trap distribution leads to the decoupling of quantum dots. Furthermore, the oscillations in the transmission and reflection coefficients increase as the plunger/barrier gate length increases, reducing the coupling between the QDs. By optimizing plunger and barrier gate dimensions, spacer configurations, and gap oxide lengths, we enhance control over quantum well depths and minimize unwanted wave function leakage. The modeling algorithm is also validated against the experimental data and can accurately capture the oscillations in the Id Vgs caused by the Coulomb blockade at cryogenic temperature