Techniques

Beside growth, nanofabrication is achieved using shared facilities such as NEEL Nanofab and Grenoble PTA (for ICP etching). Regarding characterization, the group developed electrical characterization setups specifically adapted to diamond, such as Hall effect, current-voltage and capacitance measurements. For high power electrical measurements a specific platform, CARAPACE, is being developped in collaboration with G2ELab, with a LANEF support. For other analysis the group relies mainly on NEEL technical groups, in particular the POM technical group for microRaman, CL and FTIR spectroscopies, as well as optical profilometry.

Regarding growth, three reactors have been dedicated to diamond growth in a hydrogen/methane microwave plasma cavity. With these reactors, plasma working at medium pressure drives heating of gas phase by electrons allowing high surface temperature and reactive species creation. We also add diborane gas to dope the semiconductor up to metallic transition. However, to avoid cross contamination, each reactor is dedicated to specific studies. The most recently installed (2012) is devoted to low doped and thick diamond layers for power devices (Schottky diode) and was financed by the DiamondX2 project. Recently, we also developed in situ studies with the help of a spectroscopic ellipsometer. This optical device can be easily installed on reactors to measure in real time, the thickness, the roughness and in some cases the doping level. Diamond growth studies are consequently expanding into hitherto unexplored regimes, and a new approach to control the processes is being established.

The group has also a long-standing expertise of localised growth of carbon nanotubes, studied both for their interest in bio-sensors, see scientific achievement #2, but also for high resolution AFM tips. After a careful optimisation of the patented process, yielding batches of tips with a single or double-wall nanotube on their apex, the tips were sold as a commercial product by Nanoworld company. However, after a few years of production, the market was still too small to transfer this activity to a startup or to Nanoworld. This activity has been transfered to CNRS Bordeaux. The hot filament assisted CVD apparatus dedicated to nanotube growth has also been used for diamond etching by catalytic metallic particles such as Ni or Pd. For the fabrication of samples, specific diamond technology has been developed. Regarding lithography techniques, optical and laserbeam lithography on 3x3 mm2 samples has been developed and is used routinely. For diamond etching, a process has been developped using Inductively Coupled Plasma (ICP) Reactive Ion Etching. The receipes are now routinely used on PTA’s ICP machines. A new process based on catalytic etching has also been developped, see scientific achievement #2. Finally, for gate oxide ALD deposition was explored and optimized.

To assist the design of devices, or to understand electronic properties of specific structures, we developed a new simulation activity. The two main softwares used for such studies were Nextnano+ (developped by the Walter Schottky Institute, Germany) and SILVACO. Examples of our daily use of device simulations can be found in our references on delta-doped diamond, diamond MOS, pn junction core shell GaN wire… In the case of more complex systems, or systems where the atomic scale is relevant, ab initio calculations were perfomed by our colleagues from HYBRIDE, SIN or TMC teams, which led to common publications.

Finally the last important tools for our activities are the electrical and optical characterization. The main experimental techniques were Hall effect versus temperature (from 4K to 800 K), deep level transient spectroscopy (from 77K to 873 K) and impedance spectroscopy (from 77K to 873 K and from 500 Hz to 2 MHz), as well as I(V) characteristics under a controlled atmosphere. Combined with theoretical modeling, such experiments have been used in particular to describe the scattering processes which limit the mobility in boron doped diamond, to demonstrate the wrong assignement of a BH complex to a n-type dopant, or to identify new deep traps in diamond epilayers. Apart from the optical excitation/detection system included in our DLTS system, we developed ex situ ellipsometry so as to yield thin diamond epilayer thicknesses down to the nm-level.

Cohérence quantique - CQ

Cohérence quantique - CQ

Révéler des phénomènes quantiques dans des circuits électroniques nanométriques
Hélium : du fondamental aux applications - HELFA

Hélium : du fondamental aux applications - HELFA

Hélium comme système modèle, hydrodynamique et turbulence, spatial et astrophysique, instrumentation et développement cryogénique.
Magnétisme et Supraconductivité - MagSup

Magnétisme et Supraconductivité - MagSup

Equipe Magnétisme et supraconductivité à l’Institut NEEL - Systèmes impliquant différents degrés de liberté comme la charge, le spin ou le réseau.
Optique et Matériaux - OPTIMA

Optique et Matériaux - OPTIMA

Rassembler une chaine de compétence complète qui va de la synthèse et l’élaboration de matériaux nouveaux à l’étude des propriétés optiques non linéaires et plasmoniques
Matériaux, Rayonnements, Structure - MRS

Matériaux, Rayonnements, Structure - MRS

Compréhension des propriétés physico-chimiques de matériaux complexes sur la base d’une connaissance fine de leur structure
Micro et NanoMagnétisme - MNM

Micro et NanoMagnétisme - MNM

Complementary expertise in fabrication, characterisation, and simulations for studies in nanomagnetism with applications in spin electronics and micro-systems
Nano-Electronique Quantique et Spectroscopie - QNES

Nano-Electronique Quantique et Spectroscopie - QNES

Transport électronique et spectroscopie locale de structures quantiques
Nano-Optique et Forces - NOF

Nano-Optique et Forces - NOF

Nano - optique et forces
Nanophysique et Semiconducteurs - NPSC

Nanophysique et Semiconducteurs - NPSC

Élaboration de nanostructures de semi-conducteurs III-V et II-VI et étude de leurs propriétés physiques en vue de nouvelles fonctionnalités
Nanospintronique et Transport Moléculaire - NanoSpin

Nanospintronique et Transport Moléculaire - NanoSpin

Studying magnetism at the nanoscale, where classical and quantum properties can be combined and used for molecular quantum spintronics
Semi-conducteurs à large bande interdite - SC2G

Semi-conducteurs à large bande interdite - SC2G

De la physique du diamant et autres semi-conducteurs à grand gap vers les applications en électronique et biotechnologies
Surfaces, Interfaces et Nanostructures - SIN

Surfaces, Interfaces et Nanostructures - SIN

Etudes expérimentales et théoriques de systèmes de basse dimensionnalité
Systèmes Hybrides de basse dimensionnalité - HYBRID

Systèmes Hybrides de basse dimensionnalité - HYBRID

Propriétés électroniques, optiques, vibrationnelles, mécaniques, et leur couplage à l’échelle quantique, de nouveaux systèmes hybrides (nanotubes, graphène, matériaux bi-dimensionnels, fonctionnalisés) que l’équipe développe.
Théorie de la Matière Condensée -TMC

Théorie de la Matière Condensée -TMC

Phénomènes physiques nouveaux dans les matériaux et systèmes modèles.
Thermodynamique et biophysique des petits systèmes - TPS

Thermodynamique et biophysique des petits systèmes - TPS

Instrumentation ultrasensible pour sonder les propriétés électronique et thermique : de la matière condensée à basse température aux systèmes biologiques à l’ambiante.
Théorie Quantique des Circuits - ThQC

Théorie Quantique des Circuits - ThQC

Étude théorique du transport électronique dans des dispositifs nanométriques aux propriétés quantiques remarquables.
Ultra-basses températures - UBT

Ultra-basses températures - UBT

La physique quantique à la limite des ultra-basses températures.
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