Integrated Circuits Based on 300 GHz fT Metamorphic HEMT Technology for Millimeter-Wave and Mixed-Signal Applications

Advanced circuits based on metamorphic HEMT (MHEMT)technologies on 4 ”GaAs substrates for both millimeter-wave,and mixed- signal applications are presented.Extrinsic cut-off frequencies of ft =293 GHz and fmax =337 GHz were achieved for a 70 nm gate length metamorphic HEMT echnology.The MMIC process obtains high yield on transistor and circuit level.Single-stage low-noise amplifiers demonstrate a small signal gain of 13 dB and a noise figure of 2.8 dB at 94 GHz.An amplifier MMIC developed for D-Band operation features a gain of 15 dB at 160 GHz.The achieved results are comparable to state- of-the-art InP-based HEMT technologies.In order to realize 80 Gbit/s digital circuits,a process with 100 nm gate length enhancement type HEMTs with a transit frequency of 200 GHz is used.Three metalization layers are available for interconnects.The parasitic capacitance of the interconnects is kept low by using BCB and plated air bridge technology.Based on this process,static and dynamic frequency dividers achieve a maximu toggle frequency of 70 GHz and 108 GHz,respectively

Broadband low-noise GaN HEMT TWAs using an active distributed drain bias circuit

Modern communication and radar systems show an increasing demand for robust ultra-broadband amplifiers for low-noise applications. A set of three different 0.5 GHz to 20 GHz MMIC LNAs using a GaN HEMT technology with a gate length of 0.25 μm was designed and fabricated, each with a noise figure between 3 dB and 7 dB over frequency. Two designs with four and five FET cells feature approx. 10 dB and 11 dB broadband gain, while a third MMIC with a chain connection of both figures more than 20 dB of gain. A distributed active drain bias circuit substitutes large area or off-chip inductor structures and enables a full-MMIC chain connection of both TWA stages

Phenotypic characterization of skeletal abnormalities of Osteopotentia mutant mice by micro-CT: a descriptive approach with emphasis on reconstruction techniques

PurposeThe novel protein osteopotentia (Opt) has recently been described as an essential regulator of postnatal osteoblast maturation and might possibly be responsible for some of the rarer types of osteogenesis imperfecta. Our aim was the evaluation of micro CT for the qualitative morphological assessment of skeletal abnormalities of Osteopotentia-mutant mice in comparison to radiography and histology.Materials and methodsFour homozygous mice with insertional mutations in the Opt gene and three wild-type controls were examined ex vivo using radiography and micro-CT. Two of the homozygous animals were evaluated histologically (trichrome reagent). For the micro-CT evaluation three-dimensional (3D) surface reconstructions and two-dimensional (2D) multiplanar reformations (MPRs) were applied.ResultsThe Opt-homozygous mice exhibited severe growth. The radiographic examinations showed osteopenia and fractures with hypertrophic callus formation and pseudarthroses of the forelimbs and ribs. Micro-CT confirmed these findings and was able to demonstrate additional fractures especially at smaller bones such as the metacarpals and phalanges. Additional characterization and superior delineation of cortices and fracture fragments was achieved by 2D MPRs. Histological correlation verified several of these imaging findings.ConclusionMicro-CT is able to screen Opt-mutant mice for osseous pathologies and furthermore characterize these anomalies. The modality seems superior to conventional radiography, but is not able to demonstrate cellular pathology. However, histology is destructive and more time- and material-consuming than micro-CT. Additional information may be gathered by 2D MPRs

A 183 GHz metamorphic HEMT low-noise amplifier with 3.5 dB noise figure

This paper presents a 183 GHz low-noise amplifier (LNA), designed primarly for water vapor detection in atmosphere. The LNA requirements were defined by MetOp Second Generation (MetOp-SG) Microwave Sounder, Microwave Imager and Ice Cloud Imager instruments. MetOp-SG is the European contribution to operational meteorological observations from polar orbit. This LNA advances the current state-of-the-art for the InGaAs metamorphic high electron mobility transistor (mHEMT) technology. The five-stage common-source MMIC amplifier utilizes transistors with a gate length of 50 nm. On-wafer measurements show a noise figure of 3.5 dB at the operative frequency, about 1 dB lower than previously reported mHEMT LNAs, and a gain of 24±2 dB over the bandwidth 160-200 GHz. The input and output matching are -11 dB and -10 dB, respectively. Moreover, the DC power dissipation at the optimal bias for noise is as low as 24 mW

Low noise amplifiers for MetOp-SG

We present low-noise amplifiers (LNA) that have been developed in the framework of two pre-qualification ESA projects for frequencies between 54 and 229 GHz for the METOP-SG satellite program. The main goal of these satellites is water vapor detection in atmospheric science and weather forecasting which advances the current state of the art for the metamorphic high electron mobility transistor (mHEMT) technology. The MMIC amplifiers are based on the In0.52Al0.48As/In0.8Ga0.2As/In0.53Ga0.47As heterostructure and utilize transistors with a gate length of 50 nm. On-wafer measurements will be presented for all frequency bands as well as results of packaged LNAs

Digital dynamic frequency dividers for broad band application up to 60 GHz

A broadband dynamic frequency divider based on pseudomorphic Al0.2Ga0.8As/In0.25Ga0.75As MODFETs and passive loads is presented. Stable operation from 28 GHz up to 51 GHz with a power consumption of 440 mW could be shown. SPICE network simulation predicts operation in the 35 GHz - 60 GHz range for a divider circuit using an advanced E/D AlGaAs/InGaAs MODFET process

Flip-Chip Integration of Power HEMTs: A Step Towards a GaN MMIC Technology

In this paper, flip-chip integration is demon-stratedas a method for faster progress towards a GaN MMIC technology by separating the development of active devices and passive matching circuits. This approach offers distinct advantages in the verification of passive components realized on a 2” SiC substrate. A proven 0 .3 µm GaAs PHEMT technology was used for the transistors that allowed to reproducibly verify both, the flip-chip transitions and the behaviour of the coplanar SiC structures. As an example, three X-band amplifiers in flip-chip technology are presented that demonstrate the feasibility of the technology

Frontiers of III-V Compounds and Devices 0,1

The paper presents an overview on the European status of electronic devices for micro- and mmwave applications based on III/V compound semiconductors. Both low noise and power devices for applications from a few GHz up to several hundred GHz are considered in terms of specific material and processing technologies and of typical device results. This includes a survey on the actual status of GaAs based HEMT and HBT devices, metamorphic HEMT devices. Furthermore recent results on high speed InP based HEMTs and HBTs are summarized. Regarding power applications the potentials of mature GaAs HBT technologies, power HEMTs and novel GaN technologies are discussed and compared to each other