Strained germanium thin film membrane on silicon substrate for optoelectronics

• Published in: Optics express Vol. 19; no. 27; pp. 25866 - 25872
• Main Authors: Nam, Donguk, Sukhdeo, Devanand, Roy, Arunanshu, Balram, Krishna, Cheng, Szu-Lin, Huang, Kevin Chih-Yao, Yuan, Ze, Brongersma, Mark, Nishi, Yoshio, Miller, David, Saraswat, Krishna
• Format: Journal Article
• Language: English
• Published: United States 19-12-2011
• Subjects: Electronics - instrumentation; Equipment Design; Germanium - chemistry; Germanium - radiation effects; Light; Membranes, Artificial; Optical Devices; Photometry - methods; Semiconductors; Silicon - chemistry
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/oe.19.025866

This work presents a novel method to introduce a sustainable biaxial tensile strain larger than 1% in a thin Ge membrane using a stressor layer integrated on a Si substrate. Raman spectroscopy confirms 1.13% strain and photoluminescence shows a direct band gap reduction of 100meV with enhanced light emission efficiency. Simulation results predict that a combination of 1.1% strain and heavy n(+) doping reduces the required injected carrier density for population inversion by over a factor of 60. We also present the first highly strained Ge photodetector, showing an excellent responsivity well beyond 1.6um.