This paper emphasizes for the first time the link existing between some small-signal power gain c... more This paper emphasizes for the first time the link existing between some small-signal power gain circles and the output load of maximum power in GaAs HBTs. We use the locus of power gain, named Minimum Conjugate- Termination Power, which have the value MSG/2K. MSG is maximum stable gain and K the stability factor. This method has been applied to the measurements by load-pull of 30W S-Band HBT power bar. By varying the bias of the amplifier, it is possible using only S-parameters data to localize accurately and quickly the locus of the power load.
reprint/republish or redistribute this material for advertising or promotional purposes or for cr... more reprint/republish or redistribute this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
2018 22nd International Microwave and Radar Conference (MIKON), 2018
Recent results obtained using InAlGaN/GaN HEMT technology. Material advantages of this heterostru... more Recent results obtained using InAlGaN/GaN HEMT technology. Material advantages of this heterostructure are depicted and some technological aspects are described. Low lagging effects and high electric field capability is presented. Power densities up to 10W.mm−1 have been obtained at 30GHz. MMIC power amplifiers are briefly reported.
2016 11th European Microwave Integrated Circuits Conference (EuMIC), 2016
An innovative on-wafer multi-tone load-pull (MTLP) bench is presented in this paper. It has been ... more An innovative on-wafer multi-tone load-pull (MTLP) bench is presented in this paper. It has been used to assess the linearity performances of different GaN HEMT transistors from two international foundries according to both single- and multi-carrier figures of merit. Time-domain characteristics studies suggest complementary distortion analysis. The transistors are operated at C-band in deep Class-AB. That bias appropriately copes with efficiency and linearity dilemma. The bench currently supports successful telecommunication and radar qualifications.
2015 10th European Microwave Integrated Circuits Conference (EuMIC), 2015
Limit of robustness of the GH25-10 has been investigated based on loadpull characterizations incr... more Limit of robustness of the GH25-10 has been investigated based on loadpull characterizations increasing step by step the Drain voltage and short term reliability tests. Up to 8W/mm at a drain voltage of 60V have been demonstrated without failure. 1hour RF life test time had been successfully carried out under these extremely enhanced conditions with no significant degradation. It is shown that the gate current is a major indicator for GaN based device degradation. Back simulations using the GH25-10 foundry non-linear model show a good agreement with the measurements assessing its prediction capability from 30V (safe operating area) to 60V.
L'objet du travail presente dans ce memoire concerne l'amplification de puissance hyperfr... more L'objet du travail presente dans ce memoire concerne l'amplification de puissance hyperfrequence a haut rendement, en bande x, a base de transistor bipolaire a heterojonction (hbt) gainp/gaas. Ce memoire est divise en deux parties: la premiere debute par l'etude du transistor ou doigt elementaire permettant un fonctionnement optimal en bande x et aboutit a l'optimisation du transistor multi-doigts de puissance. La seconde presente differents amplificateurs monolithiques de puissance (mmic) ou une nouvelle topologie de combinaison est mise en uvre. L'interet de l'interface gainp/gaas pour l'application transistor de puissance est dans un premier temps traite. Le choix d'une epitaxie est discute a partir des principaux parametres statiques et dynamiques (effet kirk), puis une topologie de doigt d'emetteur est proposee. Il est notamment montre l'aspect 3d du couplage electro-thermique. La topologie du tbh multi-doigts est optimisee d'un point de vue thermique et electrique. Des effets distribues sont mis en evidence dans la structure, entrainant un fonctionnement non-homogene des doigts ainsi qu'un couplage electro-thermique de doigt a doigt. Des puissances de 0. 4 a 1w sont obtenues avec des rpa de 40 a 55%. Des amplificateurs tbh de puissance mmic sont exposes et conduisent a differents resultats. Une nouvelle topologie d'integration est exposee. Celle-ci permet de reduire la surface de gaas occupee et ameliore considerablement le bilan thermique de la structure. Des puissances de 1,2. 5 et 5. 3w sont obtenus en bande x (10ghz) et ku avec des rpa associes de 30 a 35%. Ces resultats se classent parmi les meilleurs obtenus a l'aide de la technologie de transistors de puissance, et demontre l'interet de l'heterojonction gainp/gaas
1997 IEEE MTT-S International Microwave Symposium Digest, 1997
A NonLinear (NL) model of HBT obtained from I(V) and S-parameters pulsed measurements is presente... more A NonLinear (NL) model of HBT obtained from I(V) and S-parameters pulsed measurements is presented. Besides thermal effects, this model includes also two transcapacitances to take into account the Non-Quasi-Static (NQS) effects. It is shown that contrary to a Quasi-Static (QS) one, this model allows to predict accurately the behavior of the device in the whole power range as well
2007 European Microwave Integrated Circuit Conference, 2007
This paper reports on the design of a cascode GaN HEMT cell dedicated to 4-18GHz flip-chip distri... more This paper reports on the design of a cascode GaN HEMT cell dedicated to 4-18GHz flip-chip distributed power amplifier. The active device is a 8x50µm AlGaN/GaN HEMT grown on SiC substrate. The GaN-based die which integrates the active cascode cell and its matching elements is flip-chipped via electrical bumps onto an AlN substrate. The matching elements of the balanced cascode cell are composed of series capacitances on the gate of both transistors with additional resistances to insure stability and bias path. The series capacitor on the gate of the 1 st transistor is added for the distributed amplifier optimisation while the series capacitor on the gate of the 2 nd transistor is dedicated to the power balance of the cascode cell.
Industrial microwave technologies presents specific modeling issues. Foundries have to provide de... more Industrial microwave technologies presents specific modeling issues. Foundries have to provide design kits containing linear and nonlinear models which are multi-purpose, scalable and as accurate as possible. This can become quite challenging for technologies presenting complex nonlinear phenomena, such as GaN-based devices. Good trade-off among accuracy, numerical efficiency and generality can be anyway achieved, as shown in the paper.
Proceedings of 1994 IEEE Microwave and Millimeter-Wave Monolithic Circuits Symposium
A family of fully monolithic VCOs utilizing GaInP/GaAs HBTs are presented for the first time. The... more A family of fully monolithic VCOs utilizing GaInP/GaAs HBTs are presented for the first time. They operate at 14 GHz and 28 GHz with tuning bandwidths ranging from 10.7% to 19.6%. Output powers vary between -9 dBm and +3 dBm with an integrated 6 dB attenuator to reduce pulling. The fabrication yield is higher than 50%. On-wafer measurements show a
ABSTRACT GaInP/GaAs HBT technology is an excellent alternative to GaAlAs/GaAs HBTs. We present ne... more ABSTRACT GaInP/GaAs HBT technology is an excellent alternative to GaAlAs/GaAs HBTs. We present new X-Band power results both on discrete devices and on MMICs obtained using this new type of HBT. 12-2Ã30-¿m2 finger discrete devices show an output power of 1W at 10 GHz with a power added efficiency of 43% under near class A bias conditions. The dependence of the power gain on the HBT topology has been simulated and that predicts precisely the device performances. First power amplifier MMICs have been produced by Thomson-CSF. Those MMIC amplifiers achieve an output power above 1 W at 10 GHz under both CW and pulsed conditions. The power gain is higher than 12dB at 10 GHz. At the same RF frequency, the power added efficiency reaches 35% and 25% under pulsed conditions (3 ¿s, 10% duty cycle) and CW respectively. These first results are promising, and improved results are expected soon by tuning the output matching network and using higher gain devices.
Proceedings of ISSE'95 - International Symposium on Signals, Systems and Electronics, 1995
ABSTRACT First, a review of the laboratories, which have studied the GaInP/GaAs HBT for electroni... more ABSTRACT First, a review of the laboratories, which have studied the GaInP/GaAs HBT for electronic applications, is given. Then the peculiarities of this device are addressed compared to the more conventional GaAlAs/GaAs HBTs. Finally, a presentation of some recent Thomson-CSF X-band power results are presented and compared to the literature
This paper presents the results obtained on X-Band GaN MMICs developed in the frame of the Korrig... more This paper presents the results obtained on X-Band GaN MMICs developed in the frame of the Korrigan project launched by the European Defense Agency. A new step was achieved, 58W of output power with 38% PAE in X-Band were obtained using an 18mm² 2-stages amplifier. To our knowledge, these results present a new state-of-the-art of X-Band MMIC power amplifiers.
International Journal of Microwave and Wireless Technologies, 2013
This paper presents a design method of internally-matched packaged GaN high electron mobility tra... more This paper presents a design method of internally-matched packaged GaN high electron mobility transistors (HEMTs) for achieving not only high-efficiency and high-power performances but also a wide bandwidth and insensitivity to harmonic terminations in the S-band. The package and its internal matching networks are synthesized to confine the second harmonic impedances seen by the GaN die to high-efficiency regions whatever the harmonic impedances presented outside the package. This paper reports the design of a packaged GaN HEMT achieving 78% of power-added-efficiency (PAE) and 25 W of output power at 2.5 GHz. A packaged GaN power bar is also reported with the addition of fundamental matching networks inside the package. In 50 Ω environment, the packaged GaN power bar provided more than 56% of PAE from 2.5 to 3.1 GHz and was desensitized to harmonic load variations with less than two points of PAE variation when a load-pull is performed at second harmonic frequencies outside the pack...
We focus this paper on the improvement of the thermal management of power transistor based on the... more We focus this paper on the improvement of the thermal management of power transistor based on the InGaP / GaAs HBT technology and specially for pulsed mode application Applied to very HBT high power transistor, from 10W to 3W, respectively for L to Ku bands radar applications, a specific study has been done to suggest new opportunities if we take into account the transient or dynamic behavior of the transistor in pulse operating mode. From very short pulse (1 µs) to very long pulse (≈ ≈ ≈ ≈ 1 ms), a analysis has been performed with as a consequence a strong improvement of thermal impedance (Zth) through specific designs of the thermal shunt (material-shape) present at the front side. We chose to develop the concept of "thermal sponge" on power HBT transistor acting as a very efficient thermal capacitance to suppress thermal variation inside the pulse and improving as a consequence the CW thermal resistance. Two approaches have been compared : the first one with the support of very thick metal growth directly on the thin gold thermal shunt, the second one with a very small part of diamond substrate directly on top the same thermal shunt. As a conclusion, for long pulse application greater than 200 µs up to 1 ms, the diamond approach gives superior result with 30% of improvement on the temperature rising.
2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)
ABSTRACT HBT power technology offers an excellent compromise for high power and high efficiency a... more ABSTRACT HBT power technology offers an excellent compromise for high power and high efficiency amplifiers up to the Ku band. In this paper, we present the performances of GaInP/GaAs power chips. Two different approaches to thermal management were proposed for very high power levels. Pulsed power measurements of power chips integrating thick gold or diamond as heat spreaders are reported. An output power of 31 W with 49.5% of PAE was obtained at 2.9 GHz on 3.3mm2 of GaAs area. This corresponds to a power density of 9.4W/mm2. These power chips constitute very attractive chips for compact high power, high efficiency amplifiers for radar and communication systems.
GaN based technologies are promising in terms of electrical performances for power and high frequ... more GaN based technologies are promising in terms of electrical performances for power and high frequencies applications and their reliability assessment remains a burning issue. Thus, a good understanding of their degradation mechanisms is required to warranty their reliability. In this paper, an electrical parasitic effect has been observed on the gate-source diode forward characteristics of a set of devices under HTRB stress carried out at 175°C up to 4000 h. This parasitic effect has been attributed to lateral surface conduction and correlated with EL signature under diode forward biasing conditions but not under transistor pinch-off biasing conditions. Then, physical analyses have pointed out the formation and growing over time of pits and cracks at the gate edge on the drain side.
This paper emphasizes for the first time the link existing between some small-signal power gain c... more This paper emphasizes for the first time the link existing between some small-signal power gain circles and the output load of maximum power in GaAs HBTs. We use the locus of power gain, named Minimum Conjugate- Termination Power, which have the value MSG/2K. MSG is maximum stable gain and K the stability factor. This method has been applied to the measurements by load-pull of 30W S-Band HBT power bar. By varying the bias of the amplifier, it is possible using only S-parameters data to localize accurately and quickly the locus of the power load.
reprint/republish or redistribute this material for advertising or promotional purposes or for cr... more reprint/republish or redistribute this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
2018 22nd International Microwave and Radar Conference (MIKON), 2018
Recent results obtained using InAlGaN/GaN HEMT technology. Material advantages of this heterostru... more Recent results obtained using InAlGaN/GaN HEMT technology. Material advantages of this heterostructure are depicted and some technological aspects are described. Low lagging effects and high electric field capability is presented. Power densities up to 10W.mm−1 have been obtained at 30GHz. MMIC power amplifiers are briefly reported.
2016 11th European Microwave Integrated Circuits Conference (EuMIC), 2016
An innovative on-wafer multi-tone load-pull (MTLP) bench is presented in this paper. It has been ... more An innovative on-wafer multi-tone load-pull (MTLP) bench is presented in this paper. It has been used to assess the linearity performances of different GaN HEMT transistors from two international foundries according to both single- and multi-carrier figures of merit. Time-domain characteristics studies suggest complementary distortion analysis. The transistors are operated at C-band in deep Class-AB. That bias appropriately copes with efficiency and linearity dilemma. The bench currently supports successful telecommunication and radar qualifications.
2015 10th European Microwave Integrated Circuits Conference (EuMIC), 2015
Limit of robustness of the GH25-10 has been investigated based on loadpull characterizations incr... more Limit of robustness of the GH25-10 has been investigated based on loadpull characterizations increasing step by step the Drain voltage and short term reliability tests. Up to 8W/mm at a drain voltage of 60V have been demonstrated without failure. 1hour RF life test time had been successfully carried out under these extremely enhanced conditions with no significant degradation. It is shown that the gate current is a major indicator for GaN based device degradation. Back simulations using the GH25-10 foundry non-linear model show a good agreement with the measurements assessing its prediction capability from 30V (safe operating area) to 60V.
L'objet du travail presente dans ce memoire concerne l'amplification de puissance hyperfr... more L'objet du travail presente dans ce memoire concerne l'amplification de puissance hyperfrequence a haut rendement, en bande x, a base de transistor bipolaire a heterojonction (hbt) gainp/gaas. Ce memoire est divise en deux parties: la premiere debute par l'etude du transistor ou doigt elementaire permettant un fonctionnement optimal en bande x et aboutit a l'optimisation du transistor multi-doigts de puissance. La seconde presente differents amplificateurs monolithiques de puissance (mmic) ou une nouvelle topologie de combinaison est mise en uvre. L'interet de l'interface gainp/gaas pour l'application transistor de puissance est dans un premier temps traite. Le choix d'une epitaxie est discute a partir des principaux parametres statiques et dynamiques (effet kirk), puis une topologie de doigt d'emetteur est proposee. Il est notamment montre l'aspect 3d du couplage electro-thermique. La topologie du tbh multi-doigts est optimisee d'un point de vue thermique et electrique. Des effets distribues sont mis en evidence dans la structure, entrainant un fonctionnement non-homogene des doigts ainsi qu'un couplage electro-thermique de doigt a doigt. Des puissances de 0. 4 a 1w sont obtenues avec des rpa de 40 a 55%. Des amplificateurs tbh de puissance mmic sont exposes et conduisent a differents resultats. Une nouvelle topologie d'integration est exposee. Celle-ci permet de reduire la surface de gaas occupee et ameliore considerablement le bilan thermique de la structure. Des puissances de 1,2. 5 et 5. 3w sont obtenus en bande x (10ghz) et ku avec des rpa associes de 30 a 35%. Ces resultats se classent parmi les meilleurs obtenus a l'aide de la technologie de transistors de puissance, et demontre l'interet de l'heterojonction gainp/gaas
1997 IEEE MTT-S International Microwave Symposium Digest, 1997
A NonLinear (NL) model of HBT obtained from I(V) and S-parameters pulsed measurements is presente... more A NonLinear (NL) model of HBT obtained from I(V) and S-parameters pulsed measurements is presented. Besides thermal effects, this model includes also two transcapacitances to take into account the Non-Quasi-Static (NQS) effects. It is shown that contrary to a Quasi-Static (QS) one, this model allows to predict accurately the behavior of the device in the whole power range as well
2007 European Microwave Integrated Circuit Conference, 2007
This paper reports on the design of a cascode GaN HEMT cell dedicated to 4-18GHz flip-chip distri... more This paper reports on the design of a cascode GaN HEMT cell dedicated to 4-18GHz flip-chip distributed power amplifier. The active device is a 8x50µm AlGaN/GaN HEMT grown on SiC substrate. The GaN-based die which integrates the active cascode cell and its matching elements is flip-chipped via electrical bumps onto an AlN substrate. The matching elements of the balanced cascode cell are composed of series capacitances on the gate of both transistors with additional resistances to insure stability and bias path. The series capacitor on the gate of the 1 st transistor is added for the distributed amplifier optimisation while the series capacitor on the gate of the 2 nd transistor is dedicated to the power balance of the cascode cell.
Industrial microwave technologies presents specific modeling issues. Foundries have to provide de... more Industrial microwave technologies presents specific modeling issues. Foundries have to provide design kits containing linear and nonlinear models which are multi-purpose, scalable and as accurate as possible. This can become quite challenging for technologies presenting complex nonlinear phenomena, such as GaN-based devices. Good trade-off among accuracy, numerical efficiency and generality can be anyway achieved, as shown in the paper.
Proceedings of 1994 IEEE Microwave and Millimeter-Wave Monolithic Circuits Symposium
A family of fully monolithic VCOs utilizing GaInP/GaAs HBTs are presented for the first time. The... more A family of fully monolithic VCOs utilizing GaInP/GaAs HBTs are presented for the first time. They operate at 14 GHz and 28 GHz with tuning bandwidths ranging from 10.7% to 19.6%. Output powers vary between -9 dBm and +3 dBm with an integrated 6 dB attenuator to reduce pulling. The fabrication yield is higher than 50%. On-wafer measurements show a
ABSTRACT GaInP/GaAs HBT technology is an excellent alternative to GaAlAs/GaAs HBTs. We present ne... more ABSTRACT GaInP/GaAs HBT technology is an excellent alternative to GaAlAs/GaAs HBTs. We present new X-Band power results both on discrete devices and on MMICs obtained using this new type of HBT. 12-2Ã30-¿m2 finger discrete devices show an output power of 1W at 10 GHz with a power added efficiency of 43% under near class A bias conditions. The dependence of the power gain on the HBT topology has been simulated and that predicts precisely the device performances. First power amplifier MMICs have been produced by Thomson-CSF. Those MMIC amplifiers achieve an output power above 1 W at 10 GHz under both CW and pulsed conditions. The power gain is higher than 12dB at 10 GHz. At the same RF frequency, the power added efficiency reaches 35% and 25% under pulsed conditions (3 ¿s, 10% duty cycle) and CW respectively. These first results are promising, and improved results are expected soon by tuning the output matching network and using higher gain devices.
Proceedings of ISSE'95 - International Symposium on Signals, Systems and Electronics, 1995
ABSTRACT First, a review of the laboratories, which have studied the GaInP/GaAs HBT for electroni... more ABSTRACT First, a review of the laboratories, which have studied the GaInP/GaAs HBT for electronic applications, is given. Then the peculiarities of this device are addressed compared to the more conventional GaAlAs/GaAs HBTs. Finally, a presentation of some recent Thomson-CSF X-band power results are presented and compared to the literature
This paper presents the results obtained on X-Band GaN MMICs developed in the frame of the Korrig... more This paper presents the results obtained on X-Band GaN MMICs developed in the frame of the Korrigan project launched by the European Defense Agency. A new step was achieved, 58W of output power with 38% PAE in X-Band were obtained using an 18mm² 2-stages amplifier. To our knowledge, these results present a new state-of-the-art of X-Band MMIC power amplifiers.
International Journal of Microwave and Wireless Technologies, 2013
This paper presents a design method of internally-matched packaged GaN high electron mobility tra... more This paper presents a design method of internally-matched packaged GaN high electron mobility transistors (HEMTs) for achieving not only high-efficiency and high-power performances but also a wide bandwidth and insensitivity to harmonic terminations in the S-band. The package and its internal matching networks are synthesized to confine the second harmonic impedances seen by the GaN die to high-efficiency regions whatever the harmonic impedances presented outside the package. This paper reports the design of a packaged GaN HEMT achieving 78% of power-added-efficiency (PAE) and 25 W of output power at 2.5 GHz. A packaged GaN power bar is also reported with the addition of fundamental matching networks inside the package. In 50 Ω environment, the packaged GaN power bar provided more than 56% of PAE from 2.5 to 3.1 GHz and was desensitized to harmonic load variations with less than two points of PAE variation when a load-pull is performed at second harmonic frequencies outside the pack...
We focus this paper on the improvement of the thermal management of power transistor based on the... more We focus this paper on the improvement of the thermal management of power transistor based on the InGaP / GaAs HBT technology and specially for pulsed mode application Applied to very HBT high power transistor, from 10W to 3W, respectively for L to Ku bands radar applications, a specific study has been done to suggest new opportunities if we take into account the transient or dynamic behavior of the transistor in pulse operating mode. From very short pulse (1 µs) to very long pulse (≈ ≈ ≈ ≈ 1 ms), a analysis has been performed with as a consequence a strong improvement of thermal impedance (Zth) through specific designs of the thermal shunt (material-shape) present at the front side. We chose to develop the concept of "thermal sponge" on power HBT transistor acting as a very efficient thermal capacitance to suppress thermal variation inside the pulse and improving as a consequence the CW thermal resistance. Two approaches have been compared : the first one with the support of very thick metal growth directly on the thin gold thermal shunt, the second one with a very small part of diamond substrate directly on top the same thermal shunt. As a conclusion, for long pulse application greater than 200 µs up to 1 ms, the diamond approach gives superior result with 30% of improvement on the temperature rising.
2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535)
ABSTRACT HBT power technology offers an excellent compromise for high power and high efficiency a... more ABSTRACT HBT power technology offers an excellent compromise for high power and high efficiency amplifiers up to the Ku band. In this paper, we present the performances of GaInP/GaAs power chips. Two different approaches to thermal management were proposed for very high power levels. Pulsed power measurements of power chips integrating thick gold or diamond as heat spreaders are reported. An output power of 31 W with 49.5% of PAE was obtained at 2.9 GHz on 3.3mm2 of GaAs area. This corresponds to a power density of 9.4W/mm2. These power chips constitute very attractive chips for compact high power, high efficiency amplifiers for radar and communication systems.
GaN based technologies are promising in terms of electrical performances for power and high frequ... more GaN based technologies are promising in terms of electrical performances for power and high frequencies applications and their reliability assessment remains a burning issue. Thus, a good understanding of their degradation mechanisms is required to warranty their reliability. In this paper, an electrical parasitic effect has been observed on the gate-source diode forward characteristics of a set of devices under HTRB stress carried out at 175°C up to 4000 h. This parasitic effect has been attributed to lateral surface conduction and correlated with EL signature under diode forward biasing conditions but not under transistor pinch-off biasing conditions. Then, physical analyses have pointed out the formation and growing over time of pits and cracks at the gate edge on the drain side.
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