In-situ combined sensing of uniaxial nanomechanical and micromechanical stress with simultaneous measurement of surface temperature profiles by raman shift in nanoscale and microscale structures

US9778194B2 · kind B2 · utility

Assignee

• Purdue Research Foundation · US

Inventors

• Vikas Tomar · West Lafayette, US
• Ming Gan · Lo Wu, CN

Key dates

• Filing date: Jul 15, 2015
• Grant date: Oct 3, 2017
• Expiry date: Jul 18, 2035

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L1/24
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Embodiments of the present disclosure include separating a measured Raman shift signal into mechanical and thermal components when a uniaxial compressive load is applied in situ. In some embodiments, in situ uniaxial compressive loads are applied on examined specimens from room temperature to 150° C. In alternate embodiments, Raman shift measurements are performed as a function of strain at constant temperature and/or as a function of temperature at constant strain levels. It was realized that the Raman shift measured at a given temperature under a given level of applied stress can be expressed as a summation of stress-induced Raman shift signal and temperature-induced Raman shift signal measured separately. Such a separation of Raman shift signal is utilized by various embodiments to measure localized change in thermal conductivity and/or mechanical stress of structures (e.g., semiconductor structures) under applied stress.