W-Shaped Silicon Channels to Increase the Channel Perimeter and Improve the Output Current of Multi-Bridge-Channel FETs

Abstract

The development of multi-bridge-channel field-effect transistors (MBC FETs) is considered to be cutting-edge technological progress in the foundry business. However, as devices shrink, nanoscale phenomena such as the quantum confinement effect and roughness scattering become increasingly significant. These phenomena reduce the carrier density and mobility and consequently lead to a decrease in the on-state current (I_ON). Hence, increasing I_ON and the chip speed without sacrificing the chip density is crucial for advanced SoCs. In this study, to enhance I_ON, an MBC FET structure with W-shaped silicon channels is introduced for the first time. The fabrication process and electrical characteristics are simulated in TCAD simulations with a Sentaurus device. Multiple W-shaped silicon channels are created by an additional process from the starting wafer. The proposed W-shaped silicon channels have an enlarged effective perimeter compared to the flat channels of conventional MBC FETs. This design enables the generation of more electrons in the inversion layers, leading to an increase in I_ON.