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In this work, a new asymmetric lateral silicon germanium heterojunction bipolar transistor (SiGe HBT) is proposed. This asymmetric structure allows one to modulate the carrier densities in the collector region by the application of substrate bias, which causes significant improvements in device performance. The open base breakdown voltage can be tuned from 2.2 to 3.6 V and the transit frequency ( $ {f}_{\mathrm T} $ ) is improved up to ~90% by varying the substrate bias. The bias-dependent variation in transit time is elaborately discussed using regional analysis. This work, for the first time, demonstrates an oscillation frequency ( $ {f}_{ \text {MAX}} $ ) of 2.7 THz achievable by tuning the substrate bias in an asymmetric silicon-on-insulator (SOI) lateral SiGe HBT.

Nan Legeai remembers the first day she set foot in her new apartment: "I had found this tiny ad in the paper for a place overlooking the Seine, in the […]

This paper presents and discusses the challenges and solutions to calibrate the TCAD of high-speed DPSA-SEG Si/SiGe HBTs in 55-nm BiCMOS. The variation of the 1D doping profiles with the emitter width observed from EDX measurements has been addressed by TCAD simulation. Simplified base link formation by controlling the boron diffusion through polycrystalline / mono-crystalline interface in Sprocess simulation is a central step to capture a reasonable maximum oscillation frequency (fMAX). Finally all physical models including band-gap narrowing, saturation velocity, high-field mobility and SRH recombination, which impact the SiGe:C HBTs performance, are calibrated in Sdevice module of Synopsys(r).

Pour relever les défis de l’agriculture africaine, notamment de l’autosuffisance alimentaire, de la création d’emploi et de richesse, le modèle du contrat agricole est promu par certains États et bailleurs de fonds internationaux dans le cadre d’un discours performatif sur les vertus des partenariats entre agro-industries et producteurs. Toutefois, les contrats agricoles suscitent des interprétations contradictoires. Les uns en font un modèle qui aurait des effets d’entraînement sur l’économie rurale, tandis que les autres y voient des stratégies de prédation des ressources agricoles, qui sont néfastes pour les communautés locales. D’un côté comme de l’autre, les analyses restent centrées sur des questions éthiques et parfois idéologiques. Les conditions de fonctionnement des contrats et leurs impacts en termes de développement sont peu abordés. Notre contribution, basée sur des enquêtes sociologiques menées au Sénégal, vise à caractériser objectivement les formes d’interaction (positive ou négative) entre contrats agricoles et développement des territoires qui abritent une filière rizicole. C’est à partir de ces enjeux de croisement entre développement agricole et développement territorial que nous développons une démarche méthodologique permettant de réaliser ce type de diagnostic. À l’échelle des régions dominées par la riziculture, nous mettons en exergue des trajectoires territoriales contrastées par rapport à l’interaction entre modèle agricole et développement territorial. Ce diagnostic est interprété par la connaissance des systèmes d’acteurs, notamment à l’aide de deux indicateurs, à savoir : la centralité, qui donne une indication sur les questions de gouvernance territoriale, et la densité des liens, qui renseigne sur l’importance du contrat agricole par rapport à d’autres modes de mise en relation. Concernant l’insertion des contrats agricoles, la structure des réseaux d’acteurs permet d’identifier un mode de gouvernance centralisé autour de la banque agricole nationale et de quelques industriels. Mais on note aussi une persistance des rapports informels et des structures communautaires (familles, amis, voisins) qui fonctionnent en parallèle du contrat agricole et qui remettent en cause le discours politique par rapport au potentiel transformateur des contrats agricoles.

Magnesium alloyed with Ta and TaN is investigated as possible gate electrode on HfO2 dielectric. When Mg is deposited on Ta, we observe TaMg alloy formation and HfO2 degradation induced by Mg annealed at 440{degree sign}C. When TaN is deposited on HfO2 prior to Mg, TaN acts as chemical barrier against Mg diffusion and minimizes direct reaction of Mg with HfO2. TaN controls the Mg diffusion through complex mechanisms. Beside, sub-stoichiometric TaNx electrode without any additive is stable on HfO2 at 440{degree sign}C, with N+ 4.3eV band-edge work-function. We discuss on the relevance to use low-work-function additive in refractory metal gate on HfO2 dielectric.

SiGe HBTs exhibiting fmax of 400 GHz at room temperature have shown fmax value of 500 GHz at low temperature (30 K). It helps highlighting which are the limiting factors to reach 0.5 THz fmax target of the DotFive European project at room temperature.

Optimization of SiGe HBT performances towards very high cut-off frequencies fT and fMAX requires high collector doping level together with low collector/base junction capacitance CBC. This compromise is usually achieved by localizing a dedicated collector implant (so-called SIC implant) under the intrinsic emitter/base region of the device. In this paper, we present the influence of the integration choice of the Selectively Implanted Collector (SIC) on the performance of +400 GHz fMAX Si/SiGe:C HBTs featuring a selective epitaxy of the base [1]. We describe in the first part of this paper the different process flows investigated for the SIC integration. Second part is dedicated to the analysis of the electrical results obtained for the different SIC modules and to the understanding of these results. We conclude on the perspectives to further improve hf performances.

The regional transit time analysis technique is extended from 1-D to 3-D and used to investigate the AC performance of a SiGe HBT-on-SOI fabricated with a novel contact layout. As confirmed by TCAD simulations, the relocation of the base contacts out-of-plane with respect to the emitter and the collector results in a true 3-D current flow. Consequently, AC analysis and optimization cannot be performed with conventional 1-D regional transit time analysis.

A comparison of electrical performances of state-of-the-art SiGe heterojunction bipolar transistors at low temperature is presented. The performances increase results from the diminution of transit times thanks to the rise of non-stationary transport, the relative increase of the transconductance with the reduction of self-heating effects, and the decrease of access resistances.

The synchronization and/or time acquisition problem in the presence of interferences has been strongly studied these last two decades, mainly to mitigate the multiple access interferences from other users in DS/CDMA systems. Among the available receivers, only some scarce receivers may also be used in other contexts such as F/TDMA systems. However, these receivers assume implicitly or explicitly circular (or proper) interferences and become suboptimal for noncircular (or improper) interferences. Such interferences are characteristic in particular of radio communication networks using either rectilinear (or monodimensional) modulations such as BPSK modulation or modulation becoming quasirectilinear after a preprocessing such as MSK, GMSK, or OQAM modulations. For this reason, the purpose of this paper is to introduce and to analyze the performance of second-optimal array receivers for synchronization and/or time acquisition of BPSK, MSK, and GMSK signals corrupted by noncircular interferences. For given performances and in the presence of rectilinear signal and interferences, the proposed receiver allows a reduction of the number of sensors by a factor at least equal to two.

The fabrication of high speed npn SiGe HBTs requires the use of carbon to inhibit boron diffusion. The incorporation of carbon in SiGe films must be accurately controlled to avoid the formation of C-related defects. This paper describes a method which allows the development of SiGe:C processes for high performance HBTs based on photoluminescence analysis.

This paper reviews the concept, manufacturing process and electrical characteristics of a novel self-aligned SiGeC HBT structure suitable for thin-film SOI substrates. It then describes the integration of this device into 130nm SOI CMOS technology, and presents early results on the development of a complementary pnp HBT.

Profiles the Chateau de Bagnols, a historic house rescued and restored by Helen and Paul Hamlyn. Why the thirteenth-century fortified castle, seventeen miles northwest of Lyons in the core of Beaujolais wine country is now a country house hotel; Creation of some four hundred items for the new furnishings; Repairs of handsome machicolations original to the chateau; Built between 1217 and 1221 by powerful feudal lord, Guichard d'Oingt; Difficulties; More.

Features William Christie's production of the 17th century opera `Medee'. Black Mass as the pivotal dramatic scene in Medee; Adjectives used by critics about Christie's production; Christie's life and career; Founding of the Les Arts Florissants.

Magnesium alloyed with Ta and TaN is investigated as possible gate electrode on HfO2 dielectric. When Mg is deposited on Ta, we observe TaMg alloy formation and HfO2 degradation induced by Mg annealed at 440{degree sign}C. When TaN is deposited on HfO2 prior to Mg, TaN acts as chemical barrier against Mg diffusion and minimizes direct reaction of Mg with HfO2. TaN controls the Mg diffusion through complex mechanisms. Beside, sub-stoichiometric TaNx electrode without any additive is stable on HfO2 at 440{degree sign}C, with N+ 4.3eV band-edge work-function. We discuss on the relevance to use low-work-function additive in refractory metal gate on HfO2 dielectric.

Optimization of SiGe HBT performances towards very high cut-off frequencies fT and fMAX requires high collector doping level together with low collector/base junction capacitance CBC. This compromise is usually achieved by localizing a dedicated collector implant (so-called SIC implant) under the intrinsic emitter/base region of the device. In this paper, we present the influence of the integration choice of the Selectively Implanted Collector (SIC) on the performance of +400 GHz fMAX Si/SiGe:C HBTs featuring a selective epitaxy of the base [1]. We describe in the first part of this paper the different process flows investigated for the SIC integration. Second part is dedicated to the analysis of the electrical results obtained for the different SIC modules and to the understanding of these results. We conclude on the perspectives to further improve hf performances.

SiGe HBTs exhibiting fmax of 400 GHz at room temperature have shown fmax value of 500 GHz at low temperature (30 K). It helps highlighting which are the limiting factors to reach 0.5 THz fmax target of the DotFive European project at room temperature.

Data-like interference mitigation in wireless communications systems, and in mobile cellular networks in particular, has always been a challenging problem which is becoming even more so for 5G networks and beyond including the Internet of things (IoT), to support a massive number of low data rate devices for given spectral resources. A promising solution to this problem consists in using one dimensional signaling (i.e., real-valued modulations) jointly with widely linear (WL) processing at the receiver, which has the capability to process up to 2 N − 1 data-like interference from N antenna receivers, and to fulfill, for N = 1 , single antenna interference cancellation (SAIC) of a one-dimensional interference in particular. However, when the signal of interest (SOI) and observations are jointly non-Gaussian, which is the case for most of digital radiocommunications systems, WL receivers become sub-optimal and optimal receivers become non-linear. It is then of interest to propose new non-linear receivers to improve performance of WL receivers. In this context, the paper aims at introducing, for small-scale systems, third-order complex Volterra (CV) minimum mean square error (MMSE) receivers, for the reception of a digital linearly modulated SOI whose waveform is known, corrupted by potentially non-Gaussian and non-circular interference, omnipresent in practical situations. Properties, performance and adaptive implementation of these receivers in the presence of non-Gaussian and potentially non-circular interference up to the 6th-order are analyzed in this paper. In particular, some of these receivers are shown to enhance WL receiver performance for SAIC of one rectilinear interference such as binary phase-shift keying (BPSK) interference. Whereas some other receivers allow us to fulfill SAIC of 4th-order non-circular interference such as quadrature phase-shift keying (QPSK) interference, which is not possible using WL receivers. These new receivers open new perspectives for cancellation of non-Gaussian and potentially non-circular interference up to 6th-order in radiocommunication networks. [ABSTRACT FROM AUTHOR]