1,332 research outputs found
Cryogenic Characterization of 180 nm CMOS Technology at 100 mK
Conventional CMOS technology operated at cryogenic conditions has recently
attracted interest for its uses in low-noise electronics. We present one of the
first characterizations of 180 nm CMOS technology at a temperature of 100 mK,
extracting I/V characteristics, threshold voltages, and transconductance
values, as well as observing their temperature dependence. We find that CMOS
devices remain fully operational down to these temperatures, although we
observe hysteresis effects in some devices. The measurements described in this
paper can be used to inform the future design of CMOS devices intended to be
operated in this deep cryogenic regime
On the VCO/Frequency Divider Interface in Cryogenic CMOS PLL for Quantum Computing Applications
The availability of quantum microprocessors is mandatory, to efficiently run those quantum al-gorithms promising a radical leap forward in computation capability. Silicon-based nanostruc-tured qubits appear today as a very interesting approach, because of their higher information density, longer coherence times, fast operation gates, and compatibility with the actual CMOS technology. In particular, thanks to their phase noise properties, the actual CMOS RFIC Phase-Locked Loops (PLL) and Phase-Locked Oscillators (PLO) are interesting circuits to synthe-size control signals for spintronic qubits. In a quantum microprocessor, these circuits should op-erate close to the qubits, that is, at cryogenic temperatures. The lack of commercial cryogenic Design Kits (DK) may make the interface between the Voltage Controlled Oscillator (VCO) and the Frequency Divider (FD) a serious issue. Nevertheless, currently this issue has not been sys-tematically addressed in the literature. The aim of the present paper is to investigate the VCO/FD interface when the temperature drops from room to cryogenic. To this purpose, physi-cal models of electronics passive/active devices and equivalent circuits of VCO and the FD were developed at room and cryogenic temperatures. The modeling activity has led to design guide-lines for the VCO/FD interface, useful in the absence of cryogenic DKs
CMOS Quantum Computing: Toward A Quantum Computer System-on-Chip
Quantum computing is experiencing the transition from a scientific to an
engineering field with the promise to revolutionize an extensive range of
applications demanding high-performance computing. Many implementation
approaches have been pursued for quantum computing systems, where currently the
main streams can be identified based on superconducting, photonic, trapped-ion,
and semiconductor qubits. Semiconductor-based quantum computing, specifically
using CMOS technologies, is promising as it provides potential for the
integration of qubits with their control and readout circuits on a single chip.
This paves the way for the realization of a large-scale quantum computing
system for solving practical problems. In this paper, we present an overview
and future perspective of CMOS quantum computing, exploring developed
semiconductor qubit structures, quantum gates, as well as control and readout
circuits, with a focus on the promises and challenges of CMOS implementation
Cryogenic MOS Transistor Model
This paper presents a physics-based analytical model for the MOS transistor
operating continuously from room temperature down to liquid-helium temperature
(4.2 K) from depletion to strong inversion and in the linear and saturation
regimes. The model is developed relying on the 1D Poisson equation and the
drift-diffusion transport mechanism. The validity of the Maxwell-Boltzmann
approximation is demonstrated in the limit to zero Kelvin as a result of dopant
freeze-out in cryogenic equilibrium. Explicit MOS transistor expressions are
then derived including incomplete dopant-ionization, bandgap widening, mobility
reduction, and interface charge traps. The temperature dependency of the
interface-trapping process explains the discrepancy between the measured value
of the subthreshold swing and the thermal limit at deep-cryogenic temperatures.
The accuracy of the developed model is validated by experimental results on a
commercially available 28-nm bulk CMOS process. The proposed model provides the
core expressions for the development of physically-accurate compact models
dedicated to low-temperature CMOS circuit simulation.Comment: Submitted to IEEE Transactions on Electron Device
Approche industrielle aux boîtes quantiques dans des dispositifs de silicium sur isolant complètement déplété pour applications en information quantique
La mise en oeuvre des qubits de spin électronique à base de boîtes quantiques réalisés
en utilisant une technologie avancée de métal-oxyde-semiconducteur complémentaire (en
anglais: CMOS ou Complementary Metal-Oxide-Semiconductor) fonctionnant à des températures
cryogĂ©niques permet d’envisager la fabrication industrielle reproductible et Ă
haut rendement de systèmes de qubits de spin à grande échelle. Le développement d’une
architecture de boîtes quantiques à base de silicium fabriquées en utilisant exclusivement
des techniques de fabrication industrielle CMOS constitue une Ă©tape majeure dans cette
direction. Dans cette thèse, le potentiel de la technologie UTBB (en anglais: Ultra-Thin
Body and Buried oxide) silicium sur isolant complétement déplété (en anglais: FD-SOI ou
Fully Depleted Silicon-On-Insulator) 28 nm de STMicroelectronics (Crolles, France) a été
étudié pour la mise en oeuvre de boîtes quantiques bien définies, capables de réaliser des
systèmes de qubit de spin. Dans ce contexte, des mesures d’effet Hall ont été réalisées sur
des microstructures FD-SOI à 4.2 K afin de déterminer la qualité du noeud technologique
pour les applications de boîtes quantiques. De plus, un flot du processus d’intégration,
optimisé pour la mise en oeuvre de dispositifs quantiques utilisant exclusivement des méthodes
de fonderie de silicium pour la production de masse est présenté, en se concentrant
sur la réduction des risques de fabrication et des délais d’exécution globaux. Enfin, deux
géométries différentes de dispositifs à boîtes quantiques FD-SOI de 28nm ont été conçues
et leurs performances ont été étudiées à 1.4 K. Dans le cadre d’une collaboration entre
Nanoacademic Technologies, Institut quantique et STMicroelectronics, un modèle QTCAD
(en anglais: Quantum Technology Computer-Aided Design) en 3D a été développé
pour la modélisation de dispositifs à boîtes quantiques FD-SOI. Ainsi, en complément de
la caractérisation expérimentale des structures de test via des mesures de transport et de
spectroscopie de blocage de Coulomb, leur performance est modélisée et analysée à l’aide
du logiciel QTCAD. Les résultats présentés ici démontrent les avantages de la technologie
FD-SOI par rapport à d’autres approches pour les applications de calcul quantique, ainsi
que les limites identifiées du noeud 28 nm dans ce contexte. Ce travail ouvre la voie à la
mise en oeuvre des nouvelles générations de dispositifs à boîtes quantiques FD-SOI basées
sur des noeuds technologiques inférieurs.Abstract: Electron spin qubits based on quantum dots implemented using advanced Complementary Metal-Oxide-Semiconductor (CMOS) technology functional at cryogenic temperatures promise to enable reproducible high-yield industrial manufacturing of large-scale spin qubit systems. A milestone in this direction is to develop a silicon-based quantum dot structure fabricated using exclusively CMOS industrial manufacturing techniques. In this thesis, the potential of the industry-standard process 28 nm Ultra-Thin Body and Buried oxide (UTBB) Fully Depleted Silicon-On-Insulator (FD-SOI) technology of STMicroelectronics (Crolles, France) was investigated for the implementation of well-defined quantum dots capable to realize spin qubit systems. In this context, Hall effect measurements were performed on FD-SOI microstructures at 4.2 K to determine the quality of the technology node for quantum dot applications. Moreover, an optimized integration process flow for the implementation of quantum devices, using exclusively mass-production silicon-foundry methods is presented, focusing on reducing manufacturing risks and overall turnaround times. Finally, two different geometries of 28 nm FD-SOI quantum dot devices were conceived, and their performance was studied at 1.4 K. In the framework of a collaboration between Nanoacademic Technologies, Institut quantique, and STMicroelectronics, a 3D Quantum Technology Computer-Aided Design (QTCAD) model was developed for FD-SOI quantum dot device modeling. Therefore, along with the experimental characterization of the test structures via transport and Coulomb blockade spectroscopy measurements, their performance is modeled and analyzed using the QTCAD software. The results reported here demonstrate the advantages of the FD-SOI technology over other approaches for quantum computing applications, as well as the identified limitations of the 28 nm node in this context. This work paves the way for the implementation of the next generations of FD-SOI quantum dot devices based on lower technology nodes
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