Enhanced light emission from a strained germanium micro-bridge structures in telecommunication wavelength

Abstract

Si photonics based opctical interconnection are actively researched by many groups due to a possibility of great enhancement of chip-to-chip data transmission. Especially, germanium (Ge) which can be easily grown on a Si substrate is a good candidate for on-chip optical source materials because the indirect bandgap of germanium can be converted into bandgap directly by controlling the strain. In this paper, we designed and fabricated micro-bridge which control local strain for enhancing the light emission efficiency. The strain of micro-bridge was measured from the Raman spectroscopy. Also, we confirmed that the strain change in the micro-bridge followed the strain change obtained from numerical calculations well. We also analyzed the luminescence properties of Ge based micro-bridge by using photoluminescence measurement. The emission wavelength was changed depending on the strain, and the emission intensity was also increased with the increase of strain in the bridge.Our study is expected to be a milestone of Ge based optical sources fabrication.