Ge microdisk with lithographically-tunable strain using CMOS-compatible process

David S. Sukhdeo, Jan Petykiewicz, Shashank Gupta, Daeik Kim, Sungdae Woo, Youngmin Kim, Jelena Vučković, Krishna C. Saraswat, Donguk Nam
2015 Optics Express  
We present germanium microdisk optical resonators under a large biaxial tensile strain using a CMOS-compatible fabrication process. Biaxial tensile strain of ~0.7% is achieved by means of a stress concentration technique that allows the strain level to be customized by carefully selecting certain lithographic dimensions. The partial strain relaxation at the edges of a patterned germanium microdisk is compensated by depositing compressively stressed silicon nitride layer. Two-dimensional Raman
more » ... dimensional Raman spectroscopy measurements along with finite-element method simulations confirm a relatively homogeneous strain distribution within the final microdisk structure. Photoluminescence results show clear optical resonances due to whispering gallery modes which are in good agreement with finite-difference time-domain optical simulations. Our bandgap-customizable microdisks present a new route towards an efficient germanium light source for on-chip optical interconnects.
doi:10.1364/oe.23.033249 pmid:26831991 fatcat:4bidvx7m2bgefjkwvffgses7bi