54 research outputs found
FINITE ELEMENT AND IMAGING APPROACHES TO ANALYZE MULTISCALE ELECTROTHERMAL PHENOMENA
Electrothermal effects are crucial in the design and optimization of electronic devices. Thermoreflectance (TR) imaging enables transient thermal characterization at submicron to centimeter scales. Typically, finite element methods (FEM) are used to calculate the temperature profile in devices and ICs with complex geometry. By comparing theory and experiment, important material parameters and device characteristics are extracted. In this work we combine TR and FEM with image blurring/reconstruction techniques to improve electrothermal characterization of micron and nanoscale devices
Precise control of thermal conductivity at the nanoscale through individual phonon-scattering barriers
International audienceThe ability to precisely control the thermal conductivity (κ) of a material is fundamental in the development of on-chip heat management or energy conversion applications. Nanostructuring permits a marked reduction of κ of single-crystalline materials, as recently demonstrated for silicon nanowires. However, silicon-based nanostructured materials with extremely low κ are not limited to nanowires. By engineering a set of individual phonon-scattering nanodot barriers we have accurately tailored the thermal conductivity of a single-crystalline SiGe material in spatially defined regions as short as ∼15 nm. Single-barrier thermal resistances between 2 and 4×10−9 m2 K W−1 were attained, resulting in a room-temperature κ down to about 0.9 W m−1 K−1, in multilayered structures with as little as five barriers. Such low thermal conductivity is compatible with a totally diffuse mismatch model for the barriers, and it is well below the amorphous limit. The results are in agreement with atomistic Green’s function simulations
Output Power and Gain Monitoring in RF CMOS Class A Power Amplifiers by Thermal Imaging
© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The viability of using off-chip single-shot
imaging techniques for local thermal testing in integrated
Radio Frequency (RF) power amplifiers (PA’s) is analyzed.
With this approach, the frequency response of the output
power and power gain of a Class A RF PA is measured, also
deriving information about the intrinsic operation of its
transistors. To carry out this case study, the PA is
heterodynally driven, and its electrical behavior is down
converted into a lower frequency thermal field acquirable
with an InfraRed Lock-In Thermography (IR-LIT) system.
After discussing the theory, the feasibility of the proposed
approach is demonstrated and assessed with thermal
sensors monolithically integrated in the PA. As crucial
advantages to RF-testing, this local approach is noninvasive
and demands less complex instrumentation than
the mainstream commercially available solutions.Peer ReviewedPostprint (author's final draft
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