Cointegration of Gate-All-Around MOSFETs and Local Silicon-on-Insulator Optical Waveguides on Bulk Silicon

In this work we present a bulk silicon technology platform able to cointegrate gate-all-around (GAA) MOSFETs and local SOI waveguides with pentagonal cross section. Wire diagonals of 100-800 nm are obtained using a lithographic resolution of 0.8 mum. Well-functioning triangular multigate MOSFETs are reported, and tested up to 150 degC. A significant increase is observed in the low-field mobility mu₀ for small devices (W_effles500 nm), which is attributed to local volume inversion in the corners. Preliminary characterization of the optical waveguides is carried out, showing optical losses of a few dB/cm. The processing is entirely CMOS compatible, does not require access to advanced lithography equipment, and is based on a silicon bulk substrate. Thus, this technology might serve as the basis for a low-cost, high-performance optical signaling platform

I. Introduction

In this paper we present a novel versatile process in which gate-all-around (GAA) and trigate MOSFETs of various sub-m cross sections (defined by a quasi-lithographic-free method) can be fabricated along with silicon optical waveguides using standard CMOS processing steps.