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This work investigates the heat transfer between scanning thermal microscopy (SThM) probes and samples. It presents a detailed study of the heat transfer mechanisms that operate between the probe and the sample. Two SThM resistive probes of different sizes were used in active mode. Depending on the experimental conditions, the heat transferred to the sample through water meniscus, solid-solid contact...
Thermal testing of devices built on advanced compound semiconductors (GaN, SiC) is a challenge, traditional techniques provide poor results. These devices manifest temperature dependent and time variant operation, supposedly caused by capture of charge carriers on traps in the material and their later emission. The paper presents that valid test methods can be found using a systematic scan on powering...
The standard LED characterization methods do not consider changes in relative humidity of the test environment. This paper describes the effects of a high relative humidity drop on the measured light output of undomed test LED samples. The related investigation is carried out in controlled ambient conditions. Spectra of the test LED samples and of a reference light source were captured in discrete...
The thermal management of 3D chip stacks is a limiting factor in dense system integration, due to the increased volumetric power density caused by multilayer thermal interfaces. Hence, novel cooling solutions will be a key driver in realisation of these 3D integrated chip stacks. In this work the performance of a dual-side water cooling system is analysed. A numerical method utilizing porous media...
A precise monitoring on the junction temperature of the light-emitting diode (LED) packages during a lifetime tests is very helpful to make a diagnosis of their quality change and to analyse the optical degradation. We proposed a new model for internal quantum efficiency (IQE) of the LED packages as a function of the junction temperature and developed an in-situ IQE measurement system for an investigation...
A novel model order reduction method for the construction of parametric dynamic compact thermal models of nonlinear heat diffusion problems is proposed. The method extends a previous method, recently proposed by the Authors, for the construction of parametric dynamic compact thermal models of linear heat diffusion problems. The method has been validated through the analysis of a simple die in which...
Heat flux management have never been efficiently realized by the use of components that can guide, amplify or modulate radiative thermal transfer. In order to pave the way to thermal logical circuits and heat management, we study the dynamical behaviour of such theoretically conceptualized components. Using recent proposals of thermal diodes and transistors, we aim to numerically simulate their thermal...
It is shown how the objective function optimization approach fails in the construction of boundary condition independent compact thermal models of complex Systems On Silicon in which more than two powers are allowed to arbitrarily change. For such applications a novel matrix reduction approach is shown to lead to the efficient construction of accurate boundary condition independent compact thermal...
A novel matrix reduction method for the efficient and automatic construction of boundary condition independent dynamic compact thermal models having a chosen accuracy, is proposed. The method is implemented in a code which allows constructing boundary condition independent dynamic compact thermal models of any multi-die package modeled within a 3-D commercial mesher. The proposed approach has many...
The purpose of this Cooling device is to provide an energy efficient solution to cater for the ever increasing cooling requirements for IT and HVAC systems in the Data Centre and Telecoms sectors. The objective of this document is to discuss an energy rating standard for Printed Circuit Board component's which will lead to the Electronics Industry introducing an integral self cooling method of rejecting...
Within this paper, we present a guideline for the mechanical acceleration of reliability experiments for end-of-lifetime prognostics of metal based die attach materials. First, we used an advanced hybrid nano-effect sintered silver layer as interface between die and substrate which has very good electrical and thermal conductivities. Two pairs ofexperiment/simulation are scheduled. An isothermal mechanical...
In the frame of thermal management of electronic devices, finding efficient cooling solutions of the next generation equipment is a hot topic. If a new or improved solution is presented it always requires efficient characterization methods to prove the benefits compared to its predecessor. In case of microscale heatsink structures which are integral parts of modern chip or package level cooling concepts,...
This paper discusses the problem of nonlinear effects occurring in thermal modelling of electronic systems. In particular, the influence of heat transfer coefficient temperature dependence is studied based on a practical example of free convection cooled power device. The nonlinearity is identified by comparing the recorded heating and cooling curves. Additionally, the analyses are supported also...
The lifetime of aluminum electrolytic capacitors is mainly determined by their operating temperature. To simulate this temperature a finite element model of a radial type capacitor, which is mounting boundary condition (MBC) independent, is developed. Thermal parameters of the anisotropic winding are calculated by means of a lumped thermal network of the capacitor under natural convection. Finally...
An approach to thermal simulation of semiconductor ICs has been developed using a multi-block reduced-order model (ROM). The ROM projects the heat equation onto a functional space to represent the thermal solution using only a few degrees of freedom (DOF). The approach does not require any assumption on the physical geometry, dimensions, BCs or heat flow pathways. The developed approach is applied...
This paper presents a 3D integrated ultra-fast CMOS image sensor (CIS) with on-chip A/D conversions and digital storage. After an analysis of the burst IS structure and power consumption, it appears that the power density is very high (> 0.1 W/mm2) during the burst video acquisition. Therefore, to evaluate the risk of overheating, a study of the thermal dissipation in the 3D stack is described...
By using molecular dynamics technique, we have computed the effective cross-plane thermal conductivity of a single cascade of a quantum cascade laser diode. Additionally, the local phonon density of states was also computed. The Tersoff potential was used with coefficients found from the literature for inter-atomic forces, and the Green-Kubo relation was used to compute the conductivity from the integral...
3D stacking of microprocessors is an idea that promises to continue the accomplishment of high performance processors while allowing the increment of transistors density inside a given area. However, 3D stacking inevitably increases the power density and, therefore, thermal issues related to this idea must be overcome first in order to make use of all the advantages of 3D processors. In literature,...
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