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Hybrid electric and thermal modelling of semiconductor devices using the transmission line matrix (TLM) methods

Increasing the level of semiconductor devices' quality, reliability, and associated system safety is important as a fundamental contributor to overall technical advancement in the electronics sector. However, the growing requirements of optimizing device design for the broadest application areas need an enhanced level of understanding of thermal behaviour, and self-heating in particular, of semiconductor devices under harsh thermal operation conditions. The aim of the research presented in this thesis is to develop and verify a numerical tool to assist in the understanding and the prediction of phenomena that contribute to the ageing and stressing of semiconductor devices. An aged semiconductor device can substantially adversely affect a system's electromagnetic compatibility (EMC) performance and reduce the desired functionality. The chosen method is a co-simulation approach for a linked electrical and thermal model, using the Transmission Line Matrix (TLM) method. This selection is based on having a single method that can simulate both domains, that is intuitive and flexible. The method is enhanced by including electromigration and thermomigration mechanisms as an influential element in the calculation of material properties inside the hybrid solver. The proposed model was subjected to a customized Thermal Cycling Test (TCT) in order to observe device behaviour and comprehend the degradation phenomenon that Abstract appears after accelerated ageing test in RF LDMOS device. The research is a generic step forward, showing that a single TLM 'engine' can be used to model the linked factors in ageing and its effects, namely electrical, and thermal behaviour, that also allows for probabilistic events such as electro/thermo-migration. Further, the method developed in this thesis is applied to two problem areas: • Silicon nanowires, where the thermal radiation effects are addressed by adding an additional shunt conductance to a one-dimensional TLM node structure. The results demonstrate good agreement with previously published results and provide an appropriate tool to solve the internal heating problems and, hence, the degradation caused by thermal factors for future semiconductor devices. • Silicon Carbide Metal-Semiconductor Field Effect Transistor (MESFET) and RF Laterally Diffused Metal Oxide Semiconductor (LDMOS) devices, which are approached as 2D structures, where the probability of occurring electromigration and thermomigration phenomenon in MESFET devices is investigated and the MTTF is shown when the model is subjected to thermal stress. The TCT is applied as a thermal acceleration factor in a MOS device, where the impact on the device IV (current-voltage) characteristic is studied. The results demonstrated good agreement with previous published results.
Date January 2014
CreatorsAldabbagh, Ahmed
PublisherDe Montfort University
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation

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