Influence of gate work function variations on characteristics of fin-shaped silicon quantum dot device with multi-gate under existence of gate electrostatic coupling

• The variability of silicon-based quantum dot device has been studied for realizing large-scale quantum bit arrays. • Influences of work function variation (WFV) were examined focusing on fin-shaped silicon quantum dot device with a multi-gate configuration. • Threshold voltage ( V th ) of the gate stack is affected by work function variation from gates not targeted for the operation (surrounding gates). • Positive bias on the surrounding gate can improve the accuracy of the V th evaluation. • The energy level of the silicon channel can be discussed with high accuracy even under the existence of WFV in the multi-gate. We explored the effects of gate work function variation (WFV) through device simulation on a fin-shaped silicon quantum dot device with a multi-gate configuration for a large-scale integrated array. The threshold voltage ( V th ) of current–voltage characteristics is affected by WFV in both main and surrounding gates, indicating the existence of electrostatic coupling among these gates. The electrostatic coupling can be reduced by biasing on the surrounding gates. Furthermore, the concept of V th , following conventional transistors, works as a reference of voltage and potential in the present multi-gate device. This knowledge contributes to establishing a practical method for the statistical analysis of qubit variability.