Industrial GaInP/GaAs Power HBT MMIC Process

UMS has developed an industrial power HBT process especially dedicated to power MMICs in the 10GHz frequency range. The process has been qualified and meets the very demanding specifications required for X-Band high power amplifiers. Aside from the obvious RF performances, this includes the demonstration of the necessary stability and reproducibility of the process, associated with state-of-art reliability. It is important to note that the later has been achieved without affecting the high frequency capability of the devices, and demonstrated directly on high power transistors. Thanks to its intrinsic qualities this process can naturally also be used for other applications, like low phase noise voltage controlled oscillators, and power amplifiers at lower frequencies (for mobile phones for instance)

High power HBT technologies : present and trends

The HBT technology is now mature and offers a great variety of RF products for telecom applications, specially power amplifiers for which a high level of linearity is requested. The reliability has been the limiting factor in the supplying of high power amplifiers and nowadays only medium HPA are available in catalogue. Also, regarding the huge quantities of papers published in the mid 90s relating the interest of this technology for high PAE / Power, very few of the competitors have been successful. In Europe, open foundry services are available through UMS for high power applications ranging up to Ku band. New advances in term of thermal management / electrical behaviour and topology have been pushed ahead tending towards the limit of high power density. An improved version is underway to set up a doubling of the output power by cell (2.5W in X- Band). To address the market of the base stations, very high power transistors have been designed. Also, the Collector-Up DHBT offer potential improvement in term o high power at high frequency (1W at 40 GHz)

KA band satellite equipment using european GaAs technology

The present paper describes a set of GaAs MMIC developed by Alenia Aerospazio (ALS) in cooperation with United Monolithic Semiconductors (UMS) using a standard 0.25 PHEMT process. Low noise amplifiers, mixers and control functions have been implemented with excellent results, useful for all future implementations

Thermal management of power HBT inpulsed operating mode

We focus this paperon the improvement of the thermal management of power transistor based on the InGaP/GaAsHBT technology and specially for pulsed mode application Applied to very HB Thigh power transistor, from 10 W 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 transientor dynamic behavior of the transistor in pulse operating mode. From very short pulse (1µs)to very long pulse (≈1ms)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 avery 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 200µ sup to 1ms, the diamond approach gives superior result with 30%of improvement on the temperature rising

Linearisierter Verstaerker fuer Satellitenanwendungen (LVS). Arbeitspaket 4000: Validierung von MMIC Hybridschaltungen Abschlussbericht

The WP 4000 was performed in cooperation with Bosch Telecom, DaimlerChrysler Aerospace in Ulm (DASA) and in Ottobrunn (DSS) and United Monolithic Semiconductors (UMS). The aim of the program was the space evaluation of the PH25 process for production of MMIC hybrid circuits as well as the development of preamplifier linearizer circuits in C and Ku band. The PH25 process was evaluated by UMS in the frame of the program with technical support by ESA. For this purpose, UMS manufactured test structures and performed life tests with a duration of up to 4000 h with different bias and temperature conditions. During the tests, on one hand, the wear-out mechanism could be identified. On the other hand it came out that the components achieve the life time required for space applications. DASA designed the circuits for the linearizer-preamplifier device, which were manufactured at UMS, with the goal to integrate the device into the traveling wave tube. The task of DSS in this program was the manufacture of diode linearizers, which were integrated into the amplifier modules. Bosch Telecom pursued the concept of integrating the preamplifier-linearizer circuit into the power supply of the traveling wave tube. Bosch also designed circuits which were manufactured at UMS. (orig.)Available from TIB Hannover: F00B624 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany); DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Bonn (Germany)DEGerman

Effects of RF life-test on LF electrical parameters of GaAs power MESFETs

on-implanted power MESFETs have been submitted to RF life-test under gain compression. Devices went through RF life-test with no significant dynamic performance drift but with DC parameter evolution. A complete electrical characterisation performed by low frequency gate and drain noise analysis combined with drain current transient spectroscopy revealed that no degradation has occurred in the channel. An increase by two orders of magnitude of the LF gate noise level points out a degradation located in the vicinity of the gate

Measurements and control of current/ voltage waveforms of microwave transistors using an harmonic load-pull system for the optimum design of high efficiency power amplifiers

International audienceOne of the most important requirements that RF and microwave power amplifiers designed for radiocommunication systems must meet is an optimum power added efficiency (PAE) or an optimal combination of PAE and linearity. A harmonic active load-pull system which allows the control of the first three harmonic frequencies of the signal coming out of the transistor under test is a very useful tool to aid in designing optimized power amplifiers. In this paper, we present an active load-pull system coupled to a vectorial “nonlinear network” analyzer. For the first time, optimized current/voltage waveforms for maximum PAE of microwave field effect transistors (FET's) have been measured. They confirm the theory on high efficiency microwave power amplifiers. The proposed load-pull setup is based on the use of three separated active loops to synthesize load impedances at harmonics. The measurement of absolute complex power waves is performed with a broadband data acquisition unit. A specific phase calibration of the set-up allows the determination of the phase relationships between harmonic components. Therefore, voltage and current waveforms can be extracted. The measurement results of a 600 gate periphery GaAs FET (Thomson Foundry) exhibiting a PAE of 84% at 1.8 GHz are given. Such results were obtained by optimizing the load impedances at the first three harmonic components of the signal coming out of the transistor. Optimum conditions correspond to a class F operation mode of the FET (i.e., square wave output voltage and pulse shaped output current). A comparison between measured and simulated current/voltage waveforms is also presente