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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

A SiGe BiCMOS LNA for mm-wave applications

Janse van Rensburg, Christo 01 February 2012 (has links)
A 5 GHz continuous unlicensed bandwidth is available at millimeter-wave (mm-wave) frequencies around 60 GHz and offers the prospect for multi gigabit wireless applications. The inherent atmospheric attenuation at 60 GHz due to oxygen absorption makes the frequency range ideal for short distance communication networks. For these mm-wave wireless networks, the low noise amplifier (LNA) is a critical subsystem determining the receiver performance i.e., the noise figure (NF) and receiver sensitivity. It however proves challenging to realise high performance mm-wave LNAs in a silicon (Si) complementary metal-oxide semiconductor (CMOS) technology. The mm-wave passive devices, specifically on-chip inductors, experience high propagation loss due to the conductivity of the Si substrate at mm-wave frequencies, degrading the performance of the LNA and subsequently the performance of the receiver architecture. The research is aimed at realising a high performance mm-wave LNA in a Si BiCMOS technology. The focal points are firstly, the fundamental understanding of the various forms of losses passive inductors experience and the techniques to address these issues, and secondly, whether the performance of mm-wave passive inductors can be improved by means of geometry optimising. An associated hypothesis is formulated, where the research outcome results in a preferred passive inductor and formulates an optimised passive inductor for mm-wave applications. The performance of the mm-wave inductor is evaluated using the quality factor (Q-factor) as a figure of merit. An increased inductor Q-factor translates to improved LNA input and output matching performance and contributes to the lowering of the LNA NF. The passive inductors are designed and simulated in a 2.5D electromagnetic (EM) simulator. The electrical characteristics of the passive structures are exported to a SPICE netlist which is included in a circuit simulator to evaluate and investigate the LNA performance. Two LNAs are designed and prototyped using the 13μ-m SiGe BiCMOS process from IBM as part of the experimental process to validate the hypothesis. One LNA implements the preferred inductor structures as a benchmark, while the second LNA, identical to the first, replaces one inductor with the optimised inductor. Experimental verification allows complete characterization of the passive inductors and the performance of the LNAs to prove the hypothesis. According to the author's knowledge, the slow-wave coplanar waveguide (S-CPW) achieves a higher Q-factor than microstrip and coplanar waveguide (CPW) transmission lines at mm-wave frequencies implemented for the 130 nm SiGe BiCMOS technology node. In literature, specific S-CPW transmission line geometry parameters have previously been investigated, but this work optimises the signal-to-ground spacing of the S-CPW transmission lines without changing the characteristic impedance of the lines. Optimising the S-CPW transmission line for 60 GHz increases the Q-factor from 38 to 50 in simulation, a 32 % improvement, and from 8 to 10 in measurements. Furthermore, replacing only one inductor in the output matching network of the LNA with the higher Q-factor inductor, improves the input and output matching performance of the LNA, resulting in a 5 dB input and output reflection coefficient improvement. Although a 5 dB improvement in matching performance is obtained, the resultant noise and gain performance show no significant improvement. The single stage LNAs achieve a simulated gain and NF of 13 dB and 5.3 dB respectively, and dissipate 6 mW from the 1.5 V supply. The LNA focused to attain high gain and a low NF, trading off linearity and as a result obtained poor 1 dB compression of -21.7 dBm. The LNA results are not state of the art but are comparable to SiGe BiCMOS LNAs presented in literature, achieving similar gain, NF and power dissipation figures. / Dissertation (MEng)--University of Pretoria, 2012. / Electrical, Electronic and Computer Engineering / unrestricted
12

Performance prediction of a future silicon-germanium heterojunction bipolar transistor technology using a heterogeneous set of simulation tools and approaches / Prédiction de la performance d'une future technologie SiGe HBT à partir de plusieurs outils de simulation et approches

Rosenbaum, Tommy 11 January 2017 (has links)
Les procédés bipolaires semi-conducteurs complémentaires à oxyde de métal (BiCMOS) peuvent être considérés comme étant la solution la plus généralepour les produits RF car ils combinent la fabrication sophistiquée du CMOSavec la vitesse et les capacités de conduction des transistors bipolaires silicium germanium(SiGe) à hétérojonction (HBT). Les HBTs, réciproquement, sontles principaux concurrents pour combler partiellement l'écart de térahertzqui décrit la plage dans laquelle les fréquences générées par les transistors etles lasers ne se chevauchent pas (environ 0.3 THz à 30 THz). A_n d'évaluerles capacités de ces dispositifs futurs, une méthodologie de prévision fiable estsouhaitable. L'utilisation d'un ensemble hétérogène d'outils et de méthodes desimulations permet d'atteindre successivement cet objectif et est avantageusepour la résolution des problèmes. Plusieurs domaines scientifiques sont combinés, tel que la technologie de conception assistée par ordinateur (TCAO),la modélisation compacte et l'extraction des paramètres.Afin de créer une base pour l'environnement de simulation et d'améliorerla confirmabilité pour les lecteurs, les modèles de matériaux utilisés pour lesapproches hydrodynamiques et de diffusion par conduction sont introduits dèsle début de la thèse. Les modèles physiques sont principalement fondés surdes données de la littérature basées sur simulations Monte Carlo (MC) ou dessimulations déterministes de l'équation de transport de Boltzmann (BTE).Néanmoins, le module de TCAO doit être aussi étalonné sur les données demesure pour une prévision fiable des performances des HBTs. L'approchecorrespondante d'étalonnage est basée sur les mesures d'une technologie depointe de HBT SiGe pour laquelle un ensemble de paramètres spécifiques àla technologie du modèle compact HICUM/L2 est extrait pour les versionsdu transistor à haute vitesse, moyenne et haute tension. En s'aidant de cesrésultats, les caractéristiques du transistor unidimensionnel qui sont généréesservent de référence pour le profil de dopage et l'étalonnage du modèle. Enélaborant des comparaisons entre les données de références basées sur les mesureset les simulations, la thèse fait progresser l'état actuel des prévisionsbasées sur la technologie CAO et démontre la faisabilité de l'approche.Enfin, une technologie future de 28nm performante est prédite en appliquantla méthodologie hétérogène. Sur la base des résultats de TCAO, leslimites de la technologie sont soulignées. / Bipolar complementary metal-oxide-semiconductor (BiCMOS) processescan be considered as the most general solution for RF products, as theycombine the mature manufacturing tools of CMOS with the speed and drivecapabilities of silicon-germanium (SiGe) heterojunction bipolar transistors(HBTs). HBTs in turn are major contenders for partially filling the terahertzgap, which describes the range in which the frequencies generated bytransistors and lasers do not overlap (approximately 0.3THz to 30 THz). Toevaluate the capabilities of such future devices, a reliable prediction methodologyis desirable. Using a heterogeneous set of simulation tools and approachesallows to achieve this goal successively and is beneficial for troubleshooting.Various scientific fields are combined, such as technology computer-aided design(TCAD), compact modeling and parameter extraction.To create a foundation for the simulation environment and to ensure reproducibility,the used material models of the hydrodynamic and drift-diffusionapproaches are introduced in the beginning of this thesis. The physical modelsare mainly based on literature data of Monte Carlo (MC) or deterministicsimulations of the Boltzmann transport equation (BTE). However, the TCADdeck must be calibrated on measurement data too for a reliable performanceprediction of HBTs. The corresponding calibration approach is based onmeasurements of an advanced SiGe HBT technology for which a technology specific parameter set of the HICUM/L2 compact model is extracted for thehigh-speed, medium-voltage and high-voltage transistor versions. With thehelp of the results, one-dimensional transistor characteristics are generatedthat serve as reference for the doping profile and model calibration. By performingelaborate comparisons between measurement-based reference dataand simulations, the thesis advances the state-of-the-art of TCAD-based predictionsand proofs the feasibility of the approach.Finally, the performance of a future technology in 28nm is predicted byapplying the heterogeneous methodology. On the basis of the TCAD results,bottlenecks of the technology are identified. / Bipolare komplementäre Metall-Oxid-Halbleiter (BiCMOS) Prozesse bietenhervorragende Rahmenbedingungen um Hochfrequenzanwendungen zurealisieren, da sie die fortschrittliche Fertigungstechnik von CMOS mit derGeschwindigkeit und Treiberleistung von Silizium-Germanium (SiGe) Heterostruktur-Bipolartransistoren (HBTs) verknüpfen. Zudem sind HBTs bedeutendeWettbewerber für die teilweise Überbrückung der Terahertz-Lücke, derFrequenzbereich zwischen Transistoren (< 0.3 THz) und Lasern (> 30 THz).Um die Leistungsfähigkeit solcher zukünftigen Bauelemente zu bewerten, isteine zuverlässige Methodologie zur Vorhersage notwendig. Die Verwendungeiner heterogenen Zusammenstellung von Simulationstools und Lösungsansätzenerlaubt es dieses Ziel schrittweise zu erreichen und erleichtert die Fehler-_ndung. Verschiedene wissenschaftliche Bereiche werden kombiniert, wie zumBeispiel der rechnergestützte Entwurf für Technologie (TCAD), die Kompaktmodellierungund Parameterextraktion.Die verwendeten Modelle des hydrodynamischen Simulationsansatzes werdenzu Beginn der Arbeit vorgestellt, um die Simulationseinstellung zu erläuternund somit die Nachvollziehbarkeit für den Leser zu verbessern. Die physikalischenModelle basieren hauptsächlich auf Literaturdaten von Monte Carlo(MC) oder deterministischen Simulationen der Boltzmann-Transportgleichung(BTE). Für eine zuverlässige Vorhersage der Eigenschaften von HBTs muss dieTCAD Kon_guration jedoch zusätzlich auf der Grundlage von Messdaten kalibriertwerden. Der zugehörige Ansatz zur Kalibrierung beruht auf Messungeneiner fortschrittlichen SiGe HBT Technologie, für welche ein technologiespezifischer HICUM/L2 Parametersatz für die high-speed, medium-voltage undhigh-voltage Transistoren extrahiert wird. Mit diesen Ergebnissen werden eindimensionaleTransistorcharakteristiken generiert, die als Referenzdaten fürdie Kalibrierung von Dotierungspro_len und physikalischer Modelle genutztwerden. Der ausführliche Vergleich dieser Referenz- und Messdaten mit Simulationengeht über den Stand der Technik TCAD-basierender Vorhersagenhinaus und weist die Machbarkeit des heterogenen Ansatzes nach.Schlieÿlich wird die Leistungsfähigkeit einer zukünftigen Technologie in28nm unter Anwendung der heterogenen Methodik vorhergesagt. Anhand derTCAD Ergebnisse wird auf Engpässe der Technologie hingewiesen.

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