Strain-engineering in Germanium membranes towards light sources on Silicon

Bi-axially strained Germanium (Ge) is an ideal material for Silicon (Si) compatible light sources, offering exciting applications in optical interconnect technology. By employing a novel suspended architecture with an optimum design on the curvature, we applied a biaxial tensile strain as large as 0.85% to the central region of the membrane.

Introduction

Bi-axially suspended germanium membranes exhibit extremely high strain values reducing the direct bandgap and thus enhancing light emission [1], [2]. Previous works have demonstrated high biaxial strain up to 1.9% [1] and 2.4 times PL enhancements [2] by using Ge-On-Insulator (GeOI) wafers. Despite the successful demonstrations by GeOI wafers [1], [2]. the cost might be increased. We have utilized Ge on bulk Si wafers to manufacture suspended membranes.