Publications (16)8.59 Total impact
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Article: Thermal resistance of AlGaN/GaN HEMTs on SopSiC composite substrate
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ABSTRACT: In this reported work, the thermal resistance of AlGaN/GaN HEMTs processed on SopSiC composite substrate is determined by electrical I-V pulsed measurement. SopSiC substrate is based on an innovative structure with a thin Si single crystal layer transferred on top of a thick polycrystalline SiC wafer. For the first time, it is demonstrated that the thermal resistivity of such devices reaches 18.9 K mm/W when 7.5 W/mm power is dissipated, while 23.5 K mm/W are measured on silicon in the same conditions. This result shows the capabilities of composite substrates to compete with silicon for microwave power applications.Electronics Letters 07/2010; · 0.96 Impact Factor -
Article: LP MOCVD growth of InAlN/GaN HEMT heterostructure: comparison of sapphire, bulk SiC and composite SiCopSiC substrates for HEMT device applications
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ABSTRACT: In this paper we report on low-pressure metalorganic vapour deposition of InAlN/GaN heterostructures grown on different substrates (Sapphire, bulk SiC, composite SiCopSiC) for HEMT applications, and on first device performances obtained with these heterostructures. Optimisation of the crystal growth on each kind of substrate has led to InAlN/GaN HEMT heterostructures grown on bulk SiC and on composite SiCopSiC substrates which are successfully compared, in terms of material quality, to the standard GaAlN/GaN HEMT heterostructures grown on bulk SiC substrates. First devices based on InAlN/GaN heterostructures grown on bulk SiC exhibit very good microwave performances, with output power of 10.3 W/mm at 10 GHz, similar to those obtained with GaAlN/GaN heterostructures, confirming the promising potential of InAlN material. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)physica status solidi (c) 04/2010; 7(5):1317 - 1324. -
Article: Low microwave noise of AlGaN/GaN HEMTs fabricated on SiCopSiC substrates
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ABSTRACT: Low microwave noise performance of AlGaN/GaN HEMTs fabricated on MOCVD epitaxial structures grown on composite substrates (SiCopSiC) is reported. They are made of a thin SiC single-crystal layer transferred on top of a thick polycrystalline SiC wafer. The transistor fabrication process is similar to the one developed for AlGaN/GaN devices on SiC substrate. A minimum noise figure of 0.12 dB with an associated gain of 14.8 dB at 3 GHz is found, showing the capability of gallium-nitride based devices for low noise microwave applications in the S-band.Electronics Letters 02/2010; · 0.96 Impact Factor -
Conference Proceeding: Microwave power performance on AlGaN/GaN HEMTs on composite substrate
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ABSTRACT: In this paper, microwave power performance at 10 GHz of HEMTs fabricated on MOCVD and MBE epitaxial structures grown on composite substrates is demonstrated. These substrates, based on monocrystalline-SiC layer on a polycrystalline-SiC (SiCopSiC), are engineered using the Smart Cuttrade technology. They are based on innovative engineering in which a thin SiC single crystal layer is transferred on top of a thick polycrystalline SiC wafer with a thin SiO<sub>2</sub> intermediary insulating layer. The process used for the devices fabrication on SiCopSiC is quite similar to those on SiC monocrystalline bulk developed previously. High power density was measured on both epi-materials at 10 GHz. Regarding the power results for the components based on MOCVD epi-material, the best value is an output power density of 5.06 W/mm associated to a PAE of 34.7% and a linear gain of 11.8 dB at V<sub>DS</sub> = 30 V. In the frame of the MBE epilayer, the output power density is 3.58 W/mm with a maximum PAE of 25% and a linear gain around 15 dB at V<sub>DS</sub> = 40 V.Microwave Integrated Circuits Conference, 2009. EuMIC 2009. European; 10/2009 -
Article: AlGaN/GaN HEMT High Power Densities on /poly-SiC Substrates
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ABSTRACT: In this letter, successful operation at 10 GHz of T-gate HEMTs on epitaxial structures grown by metal-organic chemical vapor deposition (MOCVD) or MBE on composite substrates is demonstrated. The used device fabrication process is very similar to the process used on monocrystalline SiC substrate. High power density was measured on both epimaterials at 10 GHz. The best value is an output power density of 5.06 W/mm associated to a power-added efficiency (PAE) of 34.7% and a linear gain of 11.8 dB at V<sub>DS</sub> = 30 V for the components based on MOCVD-grown material. The output power density is 3.58 W/mm with a maximum PAE of 25% and a linear gain around 15 dB at V<sub>DS</sub> = 40 V for the MBE-grown material.IEEE Electron Device Letters 07/2009; · 2.85 Impact Factor -
Conference Proceeding: Reliability aspects of GaN-HEMTs on composite substrates
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ABSTRACT: This paper shows electrical characterizations and reliability analysis performed on AlGaN/GaN HEMTs processed on epitaxial layers grown on composite substrates. The results are very promising for the fabrication of low cost high power microwave transistors for wireless communication systems. The composite substrates constitute a valuable alternative to the silicon since better thermal properties are expected.Advanced Semiconductor Devices and Microsystems, 2008. ASDAM 2008. International Conference on; 11/2008 -
Article: Comparative study on stress in AlGaN/GaN HEMT structures grown on 6H-SiC, Si and on composite substrates of the 6H-SiC/poly-SiC and Si/poly-SiC
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ABSTRACT: The stresses in GaN-based HEMT structures grown on both single crystal 6H SiC(0001) and Si(111) have been compared to these in the HEMT structures grown on new composite substrates engendered as a thin monocrystalline film attached to polycrystalline 3C-SiC substrate. By using HRXRD technique and wafer curvature method we show that stress of monocrystalline layer in composite substrates of the type mono-Si/poly-SiC is lower than 100 MPa and residual stress of epitaxial GaN buffer grown on the composite substrate does not exceed 0.31 GPa, but in the cases of single crystal SiC or Si substrates the GaN buffer stress is compressive in the range of -0.5 ÷ -0.75 GPa. The total stress of the HEMT structure calculated from strains is consistent with the averaged stress of the multilayers stack measured by wafer curvature method. The averaged stress of HEMT structure grown on single crystals is higher than those in structures grown on composites substrates.Journal of Physics Conference Series 03/2008; 100(4):042035. -
Article: First microwave power performance of AlGaN/GaN HEMTs on SopSiC composite substrate
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ABSTRACT: The first results obtained from AlGaN/GaN HEMT devices on MBE epitaxial structures grown on 'composite' substrates are presented. These substrates are based on innovative structures in which a thin Si single crystal layer is transferred on top of a thick polycrystalline SiC wafer. The fabrication of the transistors is based on a process flow close to those used on epitaxy on Si bulk substrates. The results show the capabilities of such composite devices, providing HEMT devices for microwave power applications.Electronics Letters 02/2008; · 0.96 Impact Factor -
Conference Proceeding: Characterisation of AlGaN/GaN HEMT epitaxy and devices on composite substrates
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ABSTRACT: This paper shows results obtained on AlGaN/GaN FJEMTs processed on epitaxy grown on composite substrates. The results are very promising for the fabrication of low cost high power microwave transistors for wireless communication systems. The composite substrates constitute a valuable alternative to the silicon since better thermal properties are expected.Electron Devices Meeting, 2007. IEDM 2007. IEEE International; 01/2008 -
Conference Proceeding: AlGaN/GaN HEMTs on epitaxies grown on composite substrate
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ABSTRACT: In this paper, arc presented the first results obtained from AlGaN/GaN HEMTs devices processed on both MBE and MOCVD epitaxial structures grown on "composite" substrates. These substrates are based on innovative structures in which a thin Si or SiC single crystal layer is transferred on top of a thick polycrystalline SiC wafer with a thin SiO<sub>2</sub> intermediary insulating layer. The fabrication of the transistors is based on the process flow developed by "TIGER" for HEMT epitaxy on SiC bulk substrates. The obtained results show the capabilities of such composite devices, providing HEMT device electrical and small signal microwave performance similar to those obtained currently on bulk single crystal SiC substrates. The composite substrate approach appears as very promising for applications requiring low cost microwave power devices, such as mobile communications.Microwave Integrated Circuit Conference, 2007. EuMIC 2007. European; 11/2007 -
Conference Proceeding: A GaAsSb/InP HBT circuit technology
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ABSTRACT: A InP/GaAsSb/InP double-heterojunction bipolar transistor (DHBT) structure has been defined, realized by MBE epitaxy, and optimized, thanks to simulation based on in-depth physical characterizations. A circuit-oriented technology has been developed, which has been validated by the design and fabrication of a full-rate (40 GHz clock) 40 Gbit/s D-FF.Gallium Arsenide and Other Semiconductor Application Symposium, 2005. EGAAS 2005. European; 11/2005 -
Article: AlGaN-GaN HEMTs on Si with power density performance of 1.9 W/mm at 10 GHz
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ABSTRACT: AlGaN-GaN high electron mobility transistors (HEMTs) on silicon substrate are fabricated. The device with a gate length of 0.3-μm and a total gate periphery of 300 μm, exhibits a maximum drain current density of 925 mA/mm at V<sub>GS</sub>=0 V and V<sub>DS</sub>=5 V with an extrinsic transconductance (g<sub>m</sub>) of about 250 mS/mm. At 10 GHz, an output power density of 1.9 W/mm associated to a power-added efficiency of 18% and a linear gain of 16 dB are achieved at a drain bias of 30 V. To our knowledge, these power results represent the highest output power density ever reported at this frequency on GaN HEMT grown on silicon substrates.IEEE Electron Device Letters 08/2004; · 2.85 Impact Factor -
Conference Proceeding: InP/InGaAs-based metamorphic HBT material grown in multi-wafer production MBE system
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ABSTRACT: The InP-based materials system with InGaAs is recognized as having one of the best potential for high speed HBTs. InP/InGaAs SHBTs have demonstrated good cut-off frequencies but suffer from low breakdown voltage because of the narrow InGaAs collector energy gap. The use of InP collector in DHBTs enhances breakdown voltage by reducing impact ionisation in the collector layer. The high cost of InP substrate and the lack of 6 inch diameter limit the large volume production of InP-based devices (especially for 6 inch fab users). Using GaAs substrates with a metamorphic buffer layer allows one to reduce the cost of the epi-wafer. Moreover, DHBT structures were grown on 4-inch GaAs substrates in a production environment on a multi-wafer MBE machine. The active layers are grown on 1 mm-thick InAlAs graded buffer that matches the lattice parameter constant to InP. Optimisation of the buffer was performed to reduce both the dislocation density and the RMS surface roughness. The device structure includes a 80 nm-thick Be-doped base layer with sheet resistance of 860 ohm/sq. Preliminary results on large area device shows common-emitter current gain β = 100-110 and high breakdown voltage BVceo > 9 V. These results are approaching those published on InP substrates attesting for the high quality of the metamorphic buffer layer.Indium Phosphide and Related Materials Conference, 2002. IPRM. 14th; 02/2002 -
Conference Proceeding: InP/GaAsSb and (Al,Ga)InAs/GaAsSb DHBT material grown in a 4 inches multiwafer MBE machine
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ABSTRACT: We report results on InP/GaAsSb and (Ga,Al)InAs/GaAsSb DHBT large area devices grown by MBE in a production environment and on a 4 inch multiwafer machine. All sources are solid including that of phosphorus and antimony, except the carbon gaseous source which is CBr<sub>4</sub>. Preliminary DC characteristics obtained with a base thickness of 50 nm doped at 3.5×10<sup>19</sup> atom.cm<sup>-3</sup> giving a base resistance of 800 Ω/sq, shows a current gain 134 measured at 1 kA/cm<sup>2</sup>, which is to our knowledge the record to date in this system. It is also shown that the p-type doping concentration of the GaAsSb base can easily be reached at the level as high as 2×10<sup>20</sup> atom.cm<sup>-3</sup> while mobility remains at 27 cm<sup>2</sup> v<sup>-1</sup> sec<sup>-1</sup>. These results show that the antimony-based compounds can easily be transferred into production.Indium Phosphide and Related Materials Conference, 2002. IPRM. 14th; 02/2002 -
Article: Microwave power capabilities of AlGaN/GaN HEMTs on composite substrates
Proceedings of ESA/MOD Workshop on GaN Microwave Component Technologies. -
Article: RF Noise and Power Performances of AlGaN/GaN on Si(111) Substrates making of low cost modules.
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ABSTRACT: High performances was achieved on AlGaN/GaN HEMTs based on Si(111). Devices with 0.17-µm and 0.3-µm gate lengths are fabricated on two different layer growth at TIGER laboratory. RF noise and power performances are carried out on these transistors. The 0.17 x 100 µm2 devices exhibit a unity current gain cutoff frequency (ft) of 46 GHz, and a maximum frequency (fmax) of 92 GHz at VDS = 10 V. Also, a minimum noise figure (NFmin) of 1.1 dB and an available associated gain (Gass) of 12 dB are obtained at VDS = 10 V and f = 10 GHz. The 0.3 300 µm2 devices demonstrate a drain-to-source current density Ids = 925 mA/mm at VGS = 0 V and a maximum extrinsic transconductance (Gm) of 250 mS/mm. Furthermore, a high output power density of 1.9 W/mm associated to a PAE of 18% and a linear gain of 16 dB are measured at f = 10 GHz and VDS = 30 V. These performances are the best ever reported for AlGaN/GaN HEMTs based on silicon substrates at this frequency.
