Thermal modeling of power gallium arsenide microwave integratedcircuits

Manufacturers are developing power devices for ever higher frequencies using GaAs MESFETs and heterojunction bipolar devices constructed with III-V compounds on GaAs substrates, as well as integrated power devices on monolithic microwave integrated circuits (MMICs). A problem with the technology is the low thermal conductivity of gallium arsenide, giving rise to thermal design problems that must be solved if good reliability is to be achieved. A three-dimensional numerical simulator is used to study this problem. In particular, the approximations which are possible in performing realistic assessments of the thermal resistance of typical GaAs power device structures under steady-state conditions are examined     

Multifunction MMIC history from a process technology perspective

The different types of multifunction microwave monolithic integrated circuits (MMICs) that have been developed to date are reviewed, and projections for the future direction of the technology are made. Various innovative circuit design techniques have allowed a wide range of functions to be performed using the same processes as single-function MMICs. These circuits are almost exclusively based on GaAs Schottky-barrier-gate ion-implanted MESFETs, MIM capacitors, inductors, and (sometimes) through-substrate vias on GaAs substrates. Chips performing all the microwave functions of radar transmit/receive modules, receivers, and frequency synthesizers have been developed. Process complexity is a dominant factor determining their practicality and cost, and the most successful circuits have been designed with process limitations in mind. In the future, proliferation of multifunction MMICs with even greater functional complexity is expected, but additional process complexities will be added sparingly     

GaAs MMICs offer space and cost reductions for handheld telephones

The use of GaAs monolithic microwave integrated circuits (MMICs) for the power amplifier in portable telephones is a quantum leap in terms of technology and it affords major benefits in return especially for handheld applications. Mitsubishi has led the way in the use of MMICs and of the four current suppliers of handheld analogue telephones to the NTT telecom body in Japan, Mitsubishi is the only company using GaAs MMICs for the power amplifier in its telephones, of which it is currently producing 20 000 to 30 000 per month.     

Design of on-chip 15-18 GHz ultra low noise amplifier

With rapid development communication system, high signal to noise ratio （SNR） system is required. In high frequency bandwidth, high loss, low Q inductors and high noise figure is a significant challenge with on-chip monolithic microwave integrated circuits （MMICs）. To overcome this problem, high Q, low loss transmission line characteristics was analyzed. Compared with the same inductor value of the lumped component and the transmission line, it has a higher Q value and lower loss performance in high frequency, and a 2-stage common-source low noise amplifier （LNA） was presented, which employs source inductor feedback technology and high Q low loss transmission line matching network technique with over 17.6 dB small signal gain and 1.1 dB noise figure in 15 GHz-18 GHz. The LNA was fabricated by WIN semiconductors company 0.15 μm gallium arsenide （GaAs） P high electron mobility transistor （P-HEMT） process. The total Current is 15 mA, while the DC power consumption is only 45 mW.     

Three-dimensional MMIC technology for low-cost millimeter-waveMMICs

This paper highlights the key advantages of the three-dimensional (3-D) MMIC technology in the millimeter-wave frequency band and describes recently developed compact 3-D MMICs on GaAs and Si substrates. The 3-D MMIC technology offers high integration levels, compactness, simple design procedures, and short fabrication turn-around time, resulting in millimeter-wave MMICs at greatly reduced cost. This paper also proposes a new methodology for MMIC development based on 3-D/multilayer MMIC technology that accelerates the cost reduction of millimeter-wave MMICs. The new technology achieves compact and highly integrated millimeter-wave MMICs that are extremely cost effective     

Multifunction SAG process for high-yield, low-cost GaAs microwaveintegrated circuits

A new fully planar, multifunction refractory self-aligned gate (MSAG) technology suitable for the fabrication of GaAs small-signal and power microwave monolithic integrated circuits (MMICs) is demonstrated in a manufacturing environment. Data on the distribution of DC and RF performance and yield for pilot production of discrete FETs and MMICs are presented. The heart of the MSAG process is a planar, self-aligned gate FET. It uses a refractory TiWN Schottky gate and exhibits high performance for small-signal microwave, power microwave, and digital circuit applications. Lots with good wafer yields have demonstrated average chip yields on PCM good wafers of 45%, 49%, and 36% for 2-10-GHz distributed amplifiers, 1-W C-band power amplifiers, and 4-W power amplifiers, respectively     

A new meshing criterion for the equivalent thermal analysis of GaAs PHEMT MMICs

In this paper, a new meshing criterion for the equivalent thermal analysis of GaAs PHEMT MMICs (Monolithic microwave integrated circuit) is proposed. Based on the meshing criterion, an equivalent thermal model of GaAs PHEMTs with remarkably reduced mesh complexity is established, and the simplification of both layout pattern and vias of MMICs are performed. Theoretical analysis is applied for the calibration of the equivalent thermal model. Assisted by the meshing criterion, chip-level simulators are capable to obtain the peak temperature of MMICs without using averaging approximations, and achieve considerably high simulation accuracy. As examples, two MMIC power amplifiers are designed and implemented using GaAs PHEMT process. Thermal simulation and measurement results obtained with ANSYS ICEPAK and infrared thermography, respectively, show high consistency. The proposed meshing criterion can be applied to improve the accuracy of thermal analysis of MMICs, and the obtained precise peak temperature can be used to effectively assess the power threshold of the designed amplifiers in reliability tests.     

Advances in Gallium Arsenide Monolithic Microwave Integrated-Circuit Technology for Space Communications Systems

Future communications satellites are likely to use gallium arsenide (GaAs) monolithic microwave integrated-circuit (MMIC) technology in most, if not all, communications payload subsystems. Multiple- scanning beam antenna systems are expected to use GaAs MMIC's to increase functional capability, to reduce volume, weight, and cost, and to greatly improve system reliability. RF and IF matrix switch technology based on GaAs MMIC's is also being developed for these reasons. MMIC technology, including gigabit-rate GaAs digital integrated circuits, offers substantial advantages in power consumption and weight over silicon technologies for high-throughput, on-board baseband processor systems. In this paper, current developments in GaAs MMIC technology are described,and the status and prospects of the technology are assessed.     

GaAs MESFET ICs for gigabit logic applications

This paper gives an overview of the basic concepts used in the design and fabrication of gallium arsenide MESFET integrated circuits intended for gigabit logic applications. The present status of speed-power performances, packing densities, and integration levels is presented on the basis of some MSI and LSI MESFET IC realizations made possible by the principal GaAs logic approaches to date. Finally, the potential field of application and future trends of GaAs IC technology are assessed.     

60 GHz Single-Chip Front-End MMICs and Systems for Multi-Gb/s Wireless Communication

Single-chip 60 GHz transmitter (TX) and receiver (RX) MMICs have been designed and characterized in a 0.15mum (f_T~ 120 GHz/f _MAX> 200 GHz) GaAs mHEMT MMIC process. This paper describes the second generation of single-chip TX and RX MMICs together with work on packaging (e.g., flip-chip) and system measurements. Compared to the first generation of the designs in a commercial pHEMT technology, the MMICs presented in this paper show the same high level of integration but occupy smaller chip area and have higher gain and output power at only half the DC power consumption. The system operates with a LO signal in the range of 7-8 GHz. This LO signal is multiplied in an integrated multiply-by-eight (X8) LO multiplier chain, resulting in an IF center frequency of 2.5 GHz. Packaging and interconnects are discussed and as an alternative to wire bonding, flip-chip assembly tests are presented and discussed. System measurements are also described where bit error rate (BER) and eye diagrams are measured when the presented TX and RX MMICs transmits and receives a modulated signal. A data rate of 1.5 Gb/s with simple ASK modulation was achieved, restricted by the measurement setup rather than the TX and RX MMICs. These tests indicate that the presented MMICs are especially well suited for transmission and reception of wireless signals at data rates of several Gb/s     

2～18GHz宽带ALC放大器

介绍了自动电平控制(ALC)放大器的工作原理,研究了组成ALC系统的放大器、衰减器及检波器的特性。采用宽带理论和微波仿真软件,设计了一种2～18 GHz宽带ALC放大器,并给出了测试结果。频率为2～18 GHz,增益大于18 dB,增益平坦度小于3 dB,输入输出驻波比小于2.5,ALC动态范围大于15 dB,输出功率稳定在12.5～13.5 dBm,具有优异的宽带性能及稳定的输出。该宽带ALC放大器采用PHEMT管芯和GaAs MMIC以及微波薄膜工艺,封装在密封的金属盒体中,具有模块化、小型化的特点,应用范围广泛、前景良好。     

Lateral and vertical isolation by arsenic implantation into MOCVD-grown GaAs layers

We have demonstrated the formation of arsenic precipitates in GaAs using arsenic implantation and annealing. Electrical measurements show that very high resistivity (surface or buried) GaAs layers can be produced by this method. The arsenic-implanted materials are similar to GaAs:As buffer layers grown by low-temperature molecular beam epitaxy, which are used for eliminating backgating problems in GaAs circuits. Arsenic implantation is a nonepitaxial process which is compatible with current GaAs technology. Formation of insulating GaAs layers by this technique may improve the performance and packing density of GaAs integrated circuits, leading to advanced novel III–V compound-based technologies for high-speed and radiation-hard circuits.     

Very broadband distributed amplifier to 75 GHz

Distributed amplifiers were fabricated successfully with a gain of 8 dB+or-1 dB in the frequency range 5-75 GHz measured on-wafer. The associated input and output matching is better than -10 dB. To the authors' knowledge this is a new performance record, not only for GaAs based circuits but also for InP based MMICs. The MMICs were realised in coplanar waveguide technology.<>     

Gallium arsenide joins the giants

Gallium arsenide has enjoyed a unique position in the electronics industry for more than 25 years. GaAs is emerging as the starting material for integrated circuits with one million or more transistors per chip. The technology today is firmly in the domain of high-performance, very large-scale integration (VLSI), with chip clock rates hitting 100 MHz and up, whilst maintaining a reasonable manufacturing cost. Here, the author describes how present forms of GaAs VLSI are higher-performing versions of silicon VLSI. The GaAs transistors just speed up the same old IC concepts. Still in the future are truly novel chips, incorporating devices like optical emitters or microwave amplifiers that can be built only in GaAs III-V compounds     

Total dose and transient radiation effects on GaAs MMICs

To elucidate the effects of radiation on GaAs monolithic microwave integrated circuits (MMICs), radiation-induced changes in DC parameters of test FETs and in the measured microwave performance of MMICs were compared. Changes in material parameters determined from the DC results were used to model the observed microwave performance degradation. In addition, the effect of accumulated radiation damage in MMICs was studied in terms of the amplifier response to transient radiation pulses. The effect of 1-MeV electron irradiation on microwave response and transient radiation pulse response was measured in 0.5- to 12.5-GHz distributed amplifiers (ion-implanted) and in 28-GHz power amplifiers (with epitaxially grown active layers)     

Design and performance of wideband GaAs MMIC's for high-speedoptical communication systems

Advanced design techniques for GaAs wideband direct-coupled amplifiers are described. The amplifier achieved a 20 dB gain with a 3 dB bandwidth of 13 GHz and a 5-7 dB noise figure. An equalizing amplifier module consisting of amplifier and variable attenuator monolithic microwave integrated circuits (MMICs) exhibited a high gain of 43 dB over a 10 GHz band with a controllable gain of 20-43 dB     

GaAs digital IC technology/statistical analysis of device performance

A new approach to the design and fabrication of GaAs digital integrated circuits capable of high speed and low power dissipation has been demonstrated. This technology relies on Schottky-diode FET logic (SDFL) circuits which take advantage of the high switching speed of Schottky diodes and the high transconductance of the GaAs 1-µm gate MESFET. These circuits are fabricated by localized implantations directly into the semi-insulating GaAs substrate. Excellent results in terms of speed and power dissipation have been achieved, while circuit complexity has lrapidly grown as demonstrated by the successful operation of an eight-channel multiplexer, an eight-channel demultiplexer, and a 3 × 3 parallel multiplier employing 64, 60, and 75 gates, respectively. This rapid progress requires considerable work in monitoring the process through statistical evaluation of test devices. This paper discusses the process monitoring work carried out in support of the technology, The organization of the masks used for circuit development is described, with emphasis on process monitoring test patterns. Automatic instrumentation used to gather a large amount of statistical information is described, and wafer maps illustrating statistical results are presented and discussed. Uniformity of device characteristics over the full wafer and over smaller areas (circuit size) is compared. Implications of these results are discussed in terms of circuit yield.     

Design and performance of low-current GaAs MMICs forL-band front-end applications

GaAs monolithic microwave integrated circuits (MMICs) with very low current and of very small size have been developed for L-band front-end applications. The MMICs fully employ lumped LC elements with uniplanar configurations. There are two kinds of MMICs: a low-noise amplifier and a mixer. The low-noise amplifier has a noise figure of 2.5 dB and a gain of 11.5 dB. The mixer has a conversion gain of 12.5 dB small local oscillator (LO) power of -3 dBm. Total current dissipation of the two MMICs is less than 8 mA with 3-V drain bias voltages     

Intermixing optical and microwave signals in GaAs microstripcircuits for phase-locking applications

The microwave modulation of the interference generated by optical beams that are reflected from the top and bottom surfaces of GaAs substrate adjacent to a microstrip line is studied. The detected modulation is used to directly characterize the electrooptic effect. This optical-microwave intermixing technique is applied to phase-lock a free-running microwave oscillator with picosecond laser pulses. One potential application of this technique is for the optical on-wafer characterization of MMICs (monolithic microwave integrated circuits)     

Active inductors for GaAs and bipolar technologies

Integrated high performance gallium arsenide and silicon active inductor configurations for microwave frequencies are examined in this article. The existing topologies are considered and a new aspect of comparing the performance of different topologies based on a more complete analysis is utilised. Drawbacks of GaAs technology in this particular case are recognised, while benefits attained by using bipolar technology are presented. A theoretical basis for designing bipolar inductors is examined. On the basis of these studies a new method for raising the Q-factor of an active inductor is found and applied to two novel GaAs Q-enhanced active inductors. New applications for active high-Q resonators are found and their realisation aspects are considered. Integrated test circuits have been designed, and the simulated and experimental results are presented.