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

TL;DR

This paper introduces a novel strained-silicon trench-gate power MOSFET with improved current drive, reduced on-resistance, and enhanced transconductance, achieved through a graded SiGe buffer and strain engineering, offering better performance and damage immunity.

Contribution

It presents a new trench MOSFET design with strained Si channel and graded SiGe buffer, achieving significant performance improvements over conventional devices.

Findings

40% increase in current drivability

28% reduction in on-resistance

72% improvement in peak transconductance

Abstract

In this paper, 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 Si1-xGex body with a compositionally graded Si1-xGex 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.