A New Strained-Silicon Channel Trench-Gate Power MOSFET: Design and Analysis

In this brief, we propose a new trench power MOSFET with strained-Si channel that provides lower on-resistance than the conventional trench MOSFET. Using a 20% Ge mole fraction in the Si_1- Ge_x body with a compositionally graded Si_{1 - x}Ge_x buffer in the drift region enables us to create strain in the channel along with graded strain in the accumulation region. As a result, the proposed structure exhibits 40% enhancement in current drivability,28% reduction in the on-resistance, and 72% improvement in peak transconductance at the cost of only 12% reduction in the breakdown voltage when compared to the conventional trench-gate MOSFET. Furthermore, the graded strained accumulation region supports the confinement of carriers near the trench sidewalls, improving the field distribution in the mesa structure useful for a better damage immunity during inductive switching.