Tensile Strained Germanium Microstructures: A Comprehensive Analysis of Thermo‐Opto‐Mechanical Properties

• Published in: Physica status solidi. A, Applications and materials science Vol. 218; no. 21
• Main Authors: Manganelli, Costanza Lucia, Virgilio, Michele, Montanari, Michele, Zaitsev, Ignatii, Andriolli, Nicola, Faralli, Stefano, Tirelli, Stefano, Dagnano, Fabio, Klesse, Wolfgang Matthias, Spirito, Davide
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.11.2021
• Subjects: Finite element method; Germanium; Mechanical properties; Microstructure; Optical properties; Photoluminescence; Raman; Raman spectroscopy; semiconductor; Silicon nitride; Spectrum analysis; strain; Strain analysis; Temperature effects
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.202100293

The influence of the thermomechanical effects on the optical properties of germanium microstructures is investigated. Finite element method (FEM) calculations allow a complete spatial assessment of mechanical deformations induced by a silicon nitride (SiN) stressor layer deposited on Ge micropillars. Simulated strain maps are confirmed by experimental maps obtained by Raman spectroscopy. The theoretical investigation on strain‐dependent band structure, including the presence of a strain gradient along the longitudinal direction, is exploited to fully capture photoluminescence spectroscopy experiments. Finally, the joint effect of temperature and strain on the fundamental bandgap is also quantified. This article investigates the influence of the thermomechanical effects on the optical properties of germanium microstructures. Combining Raman spectroscopy, finite element method, and theoretical calculations, photoluminescence spectroscopy experiments are fully captured, quantifying the joint effect of temperature and strain on the fundamental gap. Highlighting critical aspects for strain‐based optoelectronic devices, this analysis can be applied to their design and characterization.