Highly strained Ge micro-blocks bonded on Si platform for Mid-Infrared photonic applications

TL;DR

This paper presents a novel method to create highly strained germanium micro-blocks on silicon, enabling mid-infrared photonic applications by inducing large tunable strains through a micro-bridge process.

Contribution

The work introduces a new fabrication process for localized, highly strained Ge micro-blocks on Si, facilitating mid-infrared optoelectronic integration.

Findings

Achieved uniaxial strains up to 4.2% in Ge micro-blocks

Demonstrated strain redistribution via micro-bridge design

Enabled potential for integrated mid-infrared photonics on Si

Abstract

Adding sufficient tensile strain to Ge can turn the material to a direct bandgap group IV semiconductor emitting in the mid-infrared wavelength range. However, highly strained-Ge cannot be directly grown on Si due to its large lattice mismatch. In this work, we have developed a process based on Ge micro-bridge strain redistribution intentionally landed to the Si substrate. Traction arms can be then partially etched to keep only localized strained-Ge micro-blocks. Large tunable uniaxial stresses up to 4.2% strain were demonstrated bonded on Si. Our approach allows to envision integrated strained-Ge on Si platform for mid-infrared integrated optics.