Si capacitive modulator integration in a 300mm silicon photonics platform with strained-SiGe to enhance the electro-optic effect.

摘要

Silicon photonic modulators are a key component for electro-optic transmitters within data centers. Electro-refractive modulators relying on free carrier plasma dispersion in a Mach-Zehnder interferometer (MZI) have become the most popular solution. Among the different electrical configurations, PN silicon modulators show a high bandwidth but at the price of a low efficiency. Accumulation-based capacitive modulators are an alternative, allowing to reduce the modulator power consumption. Additionally, strained SiGe exhibits a stronger plasma dispersion effect than silicon for holes. In this work we study thebehavior of capacitive modulators with a thin layer of strained SiGe. The modulator fabrication process is based on the standard process flow with only few add-ons. In the first demonstration we show that the thin SiGe layer improved the modulatorefficiency by 25%. In addition, furtherimprovement is possible by optimization ofthe SiGe deposition conditionto maximize the SiGe layerstress.