Optical temperature measurements on thin freestanding silicon membranes

Abstract

We report on a contactless, all-optical method to derive thermal properties of 340 nm thin, 640×640 μm(2) wide, freestanding silicon membranes. Exploiting the temperature dependent optical transmissivity of 4×10(-3)/K between 300 and 470 K, we are able to measure the temperature of the membrane with millikelvin thermal, micrometer lateral, and nanosecond temporal resolution. Experiments such as the decay of a transient thermal grating with spacings between 5 and 30 μm, measured in first order of diffraction, as well as heat diffusion in a statically heated membrane are reported in this letter. For the latter case an example of a nanostructured membrane by means of focused ion beam milling is given.

A novel contactless technique for thermal field mapping and thermal conductivity determination: Two-Laser Raman Thermometry

“…Several electrical and optical techniques have been developed to measure the thermal conductivity of a large variety of materials and structures. [1][2][3][4][5][6][7][8][9][10][11][12][13] Optical methods have recently attracted considerable attention since most of them are contactless and, thus, require few sample preparation. Such techniques can be divided into two main categories: i) steady-state techniques, [3][4][5][6][7][8] and ii) transient techniques.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] Optical methods have recently attracted considerable attention since most of them are contactless and, thus, require few sample preparation. Such techniques can be divided into two main categories: i) steady-state techniques, [3][4][5][6][7][8] and ii) transient techniques. [9][10][11][12][13] An advantage of transient techniques is that they do not require the knowledge of the absorbed power in the sample since they are only sensitive to the thermal diffusivity, α = κ/ρC p (where ρ is the density and C p the specific heat), which is usually proportional to a characteristic decay time of the system.…”

Spatially Resolved Measurement of the Stress Tensor in Thin Membranes Using Bending Waves

“…As an example, we will discuss diffusion in inhomogeneous systems. On the one hand, methods to measure the concentration [23] or the temperature [24] in particle or heatdiffusion systems as a function of space and time are known. On the other hand, inhomogeneous diffusion is a topic of continuing theoretical interest, which has been discussed for several decades [25][26][27][28][29][30][31].…”

A resonant method for determining the residual stress and elastic modulus of a thin film

“…[1][2][3][4] There is often a mismatch in the lattice or thermal expansion coefficient between the deposited thin films and the substrate, which leads to residual stress after deposition and cooling of the films. 5 The residual stress can affect the effective stiffness of the film, and hence the accurate characterisation of the film's mechanical properties, as well as the performance and reliability of filmbased devices.…”