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Faucher M.,CNRS Institute of Electronics, Microelectronics and Nanotechnology | Cordier Y.,CNRS Heteroepitaxy Applied Research Center | Werquin M.,MC2 Technologies | Buchaillot L.,CNRS Institute of Electronics, Microelectronics and Nanotechnology | And 2 more authors.
Journal of Microelectromechanical Systems | Year: 2012

We investigate the response of a GaN microelectromechanical resonator where the strain detection is performed by a resonant high-electron mobility transistor (R-HEMT). The R-HEMT gate located above the 2-DEG (two-dimensional electron gas) appears to enable a strong control of the electromechanical response with a gate voltage dependence close to a transconductance pattern. A quantitative approach based on the mobility of the carriers induced in the device by the piezoelectric response of the GaN buffer is proposed. These results show for the first time the electromechanical transconductance dependence versus external biasing and confirm that active piezoelectric transduction is governed by the AlGaN/GaN 2-DEG transport properties. © 2012 IEEE. Source


Ben Amar A.,CNRS Institute of Electronics, Microelectronics and Nanotechnology | Faucher M.,CNRS Institute of Electronics, Microelectronics and Nanotechnology | Grimbert B.,CNRS Institute of Electronics, Microelectronics and Nanotechnology | Cordier Y.,CNRS Heteroepitaxy Applied Research Center | And 8 more authors.
Applied Physics Express | Year: 2012

The piezoelectric actuation of a micro-electro-mechanical system (MEMS) resonator based on an AlGaN/GaN heterostructure is studied under various bias conditions. Using an actuator electrode that is also a transistor gate, we correlate the mechanical behaviour to the two-dimensional electron gas (2DEG) presence. The measured amplitude of the actuated resonator is maximum at moderate negative biases and drops near the pinch-off voltage in concordance with the 2DEG becoming depleted. Below the pinch-off voltage, residual actuation is still present, which is attributed to a more complex electric field pattern supported by quantitative modelling. The results confirm that epitaxial AlGaN barriers are fully adapted to the piezoelectric actuation of MEMS. © 2012 The Japan Society of Applied Physics. Source


Xu X.,Aix - Marseille University | Xu X.,University Pierre and Marie Curie | Aqua J.-N.,Aix - Marseille University | Aqua J.-N.,University Pierre and Marie Curie | And 2 more authors.
Journal of Physics Condensed Matter | Year: 2012

We study the combination of the AsaroTillerGrinfeld morphological instability of a strained film and the organizing effect of an underlying patterned substrate. We use a continuum description of surface diffusion accounting for elasticity, surface energy and wetting interactions. We solve both the mechanical equilibrium and the growth dynamics during annealing at linear order in the film modulation amplitude. We characterize the kinetic phase diagram as a function of time, the film thickness and the ratio between the substrate and the instability wavelengths. We find that the film surface can skip from a configuration in phase with the substrate to either an out-of-phase or a non-ordered configuration, depending on the pattern wavelength and annealing time. © 2012 IOP Publishing Ltd. Source


Ben Amar A.,CNRS Institute of Electronics, Microelectronics and Nanotechnology | Faucher M.,CNRS Institute of Electronics, Microelectronics and Nanotechnology | Brandli V.,CNRS Institute of Electronics, Microelectronics and Nanotechnology | Cordier Y.,CNRS Heteroepitaxy Applied Research Center | Theron D.,CNRS Institute of Electronics, Microelectronics and Nanotechnology
Physica Status Solidi (A) Applications and Materials Science | Year: 2014

This paper presents a Young's modulus extraction method for thin film group III-nitrides materials such as GaN, AlN, and its ternary AlGaN. The AlGaN/GaN heterostructures are grown by molecular beam epitaxy on Si (111) substrate and designed for MEMS applications. Various cantilevers with a width of 10μm and lengths going from 100 to 310μm were fabricated. The Young's moduli are determined using the resonance frequencies measured by laser Doppler vibrometry (LDV). Finite element modeling (FEM) is used to consider the under-etching of the cantilevers at the anchor. In this study, we find that the Young moduli of GaN and AlN layers are respectively 261±60GPa and 339±78GPa that compares well with the results found in the literature for bulk materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Dasilva Y.A.R.,CNRS Center for Research on Ions, Materials and Photonics | Ruterana P.,CNRS Center for Research on Ions, Materials and Photonics | Lahourcade L.,INAC SP2M PSC | Monroy E.,INAC SP2M PSC | Nataf G.,CNRS Heteroepitaxy Applied Research Center
Materials Science Forum | Year: 2010

In the fabrication GaN-based devices, several growth orientations are currently under investigation in order to exploit material properties which are inaccessible using layers grown along the c-axis. However, such procedures rely on foreign substrates with large misfits. Therefore, complex crystallographic defects form in the epitaxial layers and have been the subject of extensive studies. They include threading dislocations and stacking faults, which can be within basal or prismatic planes. Out of the c-axis, depending on the growth orientation, the glide planes of perfect dislocations may be no longer available, complicating the relaxation processes. © (2010) Trans Tech Publications. © (2010) Trans Tech Publications. Source

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