Mathematical Modelling of Low-Frequency BiCMOS Near-Infrared Detector

dc.contributor.advisorSinha, Saurabh
dc.contributor.emailjventer.pretoria@gmail.comen_ZA
dc.contributor.postgraduateVenter, Johan
dc.date.accessioned2020-03-16T07:17:37Z
dc.date.available2020-03-16T07:17:37Z
dc.date.created2020-09
dc.date.issued2020-03
dc.descriptionThesis (PhD (Electronic Engineering))--University of Pretoria, 2020.en_ZA
dc.description.abstractBipolar complementary metal-oxide semiconductor (BiCMOS) technology is the platform of choice for near-Infrared (IR) detector research because of low power consumption, increased operating speed and a high fill-factor. The drawback is poor noise performance which can be attributed to the readout circuitry of the detector. Conventional near-IR detector design is an iterative process. While recognising the value of this approach, rapid prototyping can be achieved by using mathematical modelling that would ensure design repeatability. Heterojunction bipolar transistor (HBT) and metal-oxide field-effect transistors (MOSFET) models for SiGe process technologies have been documented extensively. However, mathematical modelling of BiCMOS near-IR detectors has not been implemented in a complete working system before. This proposed model can be used to determine the output voltage as well as the noise performance of near-IR detectors. The focus of this research is to determine how process independent parameters and detector performance can be mathematically modelled. Secondly, and associated to this, is determining how the model can be extended to accommodate multiple feature sizes including short-channel MOSFETs. An implementation of this model on the three-transistor pixel structure, using reverse-biased diode-connected HBTs as pixels, was done as part of the experimental verification process of this research. The implementation was done in a 2 × 2 gated array detector configuration. The validity of the proposed modelling procedure was verified through comparison of simulations and measured results. The simulations were done in an iterative fashion to show how a deviation in one process independent parameter affects the noise performance, while the other process independent parameters are kept constant. The detector design with optimal noise performance can be achieved in this manner, thereby minimising design time and developing optimised detectors without the need for extensive prototyping. The main contribution of this research is that a designer can use this mathematical model to tune a detector to achieve desired performance. By changing the temperature, biasing voltage and biasing current and choosing the aspect ratio, noise performance changes. An iterative process in the mathematical model development can achieve optimised parameters for noise performance. Two approaches, namely DC analysis and y-parameter representation, were used to develop the mathematical model. Feedback was taken into account using the y-parameter representation. The measured results show that the output voltage behaviour follows the mathematical model developed. The output voltage behaviour also shows that the mathematical model parameters can determine noise performance. As an extension to this work, the same modelling process can be used to develop mathematical models for other detecting structures such as the four-transistor pixel structure.en_ZA
dc.description.availabilityUnrestricteden_ZA
dc.description.degreePhD (Electronic Engineering)en_ZA
dc.description.departmentElectrical, Electronic and Computer Engineeringen_ZA
dc.description.sponsorshipOptronic Sensor Systems, Defence, Peace, Safety and Security (DPSS), Council for Scientific and Industrial Research (CSIR), South Africaen_ZA
dc.description.sponsorshipArmscor, Armaments Corporation of South Africa Limited Act, Act No 51 of 2003en_ZA
dc.description.sponsorshipDepartment of International Relations, University of Pretoria, South Africaen_ZA
dc.description.sponsorshipNational Research Foundation (NRF), South Africaen_ZA
dc.identifier.citationVenter, J 2020, Mathematical Modelling of Low-Frequency BiCMOS Near-Infrared Detector, PhD (Electronic Engineering) Thesis, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/73756>en_ZA
dc.identifier.otherS2020en_ZA
dc.identifier.urihttp://hdl.handle.net/2263/73756
dc.language.isoenen_ZA
dc.publisherUniversity of Pretoria
dc.rights© 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
dc.subjectElectronic Engineeringen_ZA
dc.subjectUCTD
dc.titleMathematical Modelling of Low-Frequency BiCMOS Near-Infrared Detectoren_ZA
dc.typeThesisen_ZA

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