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We have developed 0.1- $\mu \text{m}$ gate-length InAlN/GaN high electron-mobility transistors (HEMTs) for millimeter-wave (MMW) power applications, particularly at 71–76 and 81–86 GHz bands. The impacts of depth and width of the gate recess groove on electrical performance have been analyzed and compared. Competing passivation technologies, atomic layer deposition (ALD) aluminum oxide (Al2O3) and plasma-enhanced chemical vapor deposition (PECVD) SiN, have also been assessed in terms of dc, pulsed- $IV$ , and high-frequency characteristics. It has been found that while PECVD SiN-passivated HEMTs and the monolithic microwave integrated circuits slightly underperform their ALD Al2O3-passivated counterparts, their MMW power performance can be further boosted with the gate recess due to the improved aspect ratio and scaling characteristics. When biased at a drain voltage of 10 V, a first-pass two-stage power amplifier design based on recessed PECVD SiN-passivated 0.1- $\mu \text{m}$ depletion-mode devices has demonstrated an output power of 1.63 W with a 15% power-added efficiency at 86 GHz.

High-performance 0.1- $\mu \text{m}$ InAlN/GaN high electron-mobility transistors (HEMTs) have been successfully developed for power amplifiers operating at E-band (targeting 71–76 and 81–86-GHz bands). High maximum drain current of 1.75 A/mm and maximum extrinsic transconductance of 0.8 S/mm have been achieved for depletion-mode devices. Enhancement-mode HEMTs have also shown maximum drain current of 1.5 A/mm and maximum extrinsic transconductance of 1 S/mm. The selection of atomic layer deposition aluminum oxide (Al2O3) for device passivation enables a two-terminal breakdown voltage of $\sim 25$ V, excellent subthreshold characteristics as well as the pulsed- IV featuring little current collapse for both types of HEMTs. When biased at a drain voltage of 10 V, a first-pass two-stage power amplifier design based on 0.1- $\mu \text{m}$ depletion-mode devices has demonstrated an output power of 1.43 W with 12.7% power-added efficiency at 86 GHz, a level of performance that has been attained previously only by state-of-the-art counterparts based on AlGaN/GaN HEMTs at a much higher drain bias and compression level.

Whereas gate-length reduction has served as the major driving force to enhance the performance of GaAs- and InP-based high-electron mobility transistors (HEMTs) over the past three decades, the limitation of this approach begins to emerge. In this paper, we present a systematic evaluation of the impact of greatly reduced source-drain spacing on the performance of 50-nm asymmetrically recessed metamorphic HEMTs (MHEMTs). Extremely high extrinsic transconductance has been achieved over a wide drain bias range starting from as low as 0.1 V by reducing source-drain spacing to 0.5 μm with a self-aligned (SAL) ohmic process. The measured maximum extrinsic transconductance of 3 S/mm is a new record for all HEMT devices on a GaAs substrate and is equal to the best results reported for InP-based HEMTs. With the use of an asymmetric recess, SAL MHEMTs also demonstrate remarkable improvement in other major figures of merit, including off-state breakdown, on-state breakdown, subthreshold characteristics, ION/IOFF ratio, and the voltage gain over the other SAL HEMTs reported so far. However, they still, in a few respects, under perform the conventional devices typically with 2-μm source-drain spacing. In particular, the on-state breakdown of the SAL devices has been capped at approximately 2 V, even with a very wide asymmetric recess. It appears that the uniqueness of the SAL technology would best fit applications that require low voltage and/or low DC power consumption, which can be fully tapped only when the parasitic capacitance is also properly controlled with, e.g., a high stem gate process.

We report the design, fabrication and characterization of metamorphic high electron-mobility transistors (MHEMTs) with self-aligned ohmic electrodes. In this work, asymmetrically recessed 50-nm Γ-gates have been successfully used as the shadow mask for ohmic metal deposition. Extremely high extrinsic transconductance over a wide drain bias from 0.1 to 1.25 V can be made possible by fabricating devices with small gate-source spacing, small source-drain spacing, and the non-alloyed ohmic. Measured maximum extrinsic transconductance of 3 S/mm is a new record for all HEMT devices on GaAs and equals the best results from InP -based HEMTs. The same devices also show a voltage gain of 22, maximum stable gain of 10.8 dB at 110 GHz, and breakdown voltage of 4.3 V, which all are the highest among any self-aligned HEMTs based on InGaAs channel. The outstanding performance is the result of the seamless integration of the asymmetric gate recess and Γ-gate-based self-aligned ohmic process.

We have fabricated and characterized ultrashort gate-length metamorphic high-electron mobility transistors (HEMTs) optimized for high gain performance for millimeter- and submillimeter-wave applications. In this paper, we have systematically evaluated the impact of gate length in the range of 25-50 nm on the device performance by exploring epitaxial layer designs, gate-to-channel distances, and recess widths. The study shows the 25-nm devices underperform their 50-nm counterparts in most of the key figures of merit including output conductance, voltage gain, off-state breakdown, on-state breakdown, and, most importantly, the maximum stable gain. This observation is actually in good agreement with the state-of-the-art results published so far, which indicate that the best overall performance of HEMTs for millimeter- and submillimeter-wave applications comes from devices with gate lengths ranging from 35 to 50 nm. The 25-nm devices, on the other hand, appear to have difficulty in achieving the proper vertical scaling for optimum gain, which is limited by the minimum gate layer thickness necessary to retain good Schottky characteristics. This limitation may eventually be overcome with the adoption of new materials used as the gate layer that can be integrated into the HEMT fabrication process.

This paper reports a successful improvement of the low breakdown voltages in short gate-length metamorphic high electron-mobility transistors. The technical approach includes both the optimization of the epitaxial layer design and the selection of the proper gate recess scheme. By employing a novel epitaxial design (including a high indium composite channel and the double-sided doping) and an asymmetric gate recess, both the off-state and on-state breakdown voltages have been improved for 50-nm high-performance metamorphic high electron-mobility transistors. The results reported herein demonstrate that these devices are excellent candidates for ultra-high-frequency power applications.

We report the design, fabrication and characterization of ultrahigh gain metamorphic high electron-mobility transistors. In this letter, a high-yield 50-nm T-gate process was successfully developed and applied to epitaxial layers containing high indium mole fraction InGaAs channels grown on GaAs substrates. A unique gate recess process was adopted to significantly increase device gain by effectively suppressing output conductance and feedback capacitance. Coupled with extremely small 10 mum times 25 mum via holes on substrates thinned to 1 mil, we achieved a 13.5 dB maximum stable gain (MSG) at 110 GHz for a 30-mum gate-width device. To our knowledge, this is the highest gain performance reported for microwave high electron-mobility transistor devices of similar gate periphery at this frequency, and equivalent circuit modeling indicates that this device will operate at frequencies beyond 300 GHz.

We present a novel micro-heat pipe wick design and fabrication technique to significantly boost the effective thermal conductivity of the heat pipe relative to the monolithic substrate material. Extensive porous flow modeling of the process has provided critical information on the key parameters and the resulting anisotropic wick designs have shown robust performance improvements. A methanol charged copper device reported in this paper showed a maximum thermal conductivity of 760 W/m K prior to dry out. This represents a 1.9× increase over the conductivity of solid copper.

A 50nm MHEMT millimeter-wave MMIC low noise amplifier with state-of-the-art performance is reported. The 3-stage LNA exhibits on-wafer noise figure (NF) as low as 1.6dB with 25dB gain at 80GHz, and also shows unprecedented wideband performance, with 20dB minimum gain across the 30-100GHz band and NF

We report the design, fabrication, and characterization of ultrahigh-gain metamorphic high-electron-mobility transistors (MHEMTs) with significantly enhanced breakdown performance. In this letter, an asymmetrically recessed 50-nm Gamma-gate process has been successfully applied to epitaxial designs with double-sided-doped InAs-layer-inserted channels grown on GaAs substrates. The critical gate recess width has been optimized for device performance, including transconductance, breakdown voltage, and gain. The employment of a device passivation process greatly minimizes the adverse impacts that the aggressive vertical and lateral scaling would have introduced for pursuing enhanced performance. As a result, we have achieved 1.9-S/mm transconductance and 800-mA/mm maximum drain current at a drain bias of 1 V, 9-V off-state breakdown voltage, approximately 3.5-V on-state breakdown voltage, and 14.2-dB maximum stable gain at 110 GHz. To our knowledge, this is a record combination of gain and breakdown performance reported for microwave and millimeter-wave HEMTs, making these devices excellent candidates for ultrahigh-frequency power applications.

The authors have used chemical vapor deposition to grow ternary tungsten-based diffusion barriers to determine if they exhibit properties similar to those of sputter-deposited ternaries. A range of different W-B-N compositions in a band of compositions roughly between 20 and 40% W were produced. The deposition temperature was low, 350 C, and the precursors used are well accepted by the industry. Deposition rates are high for a diffusion barrier application. Resistivities range from 200 to 20,000 {micro}{Omega}-cm, the films with the best barrier properties having {approximately}1,000 {micro}{Omega}-cm resistivities. Adhesion to oxides is sufficient to allow these films to be used as the adhesion layer in a tungsten chemical mechanical polishing plug application. The films are x-ray amorphous as-deposited and have crystallization temperatures of up to 900 C. Barrier performance against Cu has been tested using diode test structures. A composition of W{sub .23}B{sub .49}N{sub .28} was able to prevent diode failure up to a 700 C, 30 minute anneal. These materials, deposited by CVD, display properties similar to those deposited by physical deposition techniques.

This paper reviews recent progress in the development of GaAs Metamorphic HEMT (MHEMT) technology for microwave, millimeter-wave, and submillimeter-wave applications. Short gate-length (50-100 nm) Metamorphic High Electron Mobility Transistors have been optimized for high gain and low noise performance. Efforts to further improve performance, manufacturability, and verify reliability will be reported. We also describe the design and performance of low noise MMIC amplifiers based on this technology.

In recent rapid solidification experiments on Al—5%Be alloys, a Liquid Phase Nucleation (LPN) model was developed to explain the formation of periodic arrays of randomly-oriented Be-rich particles in an Al-rich matrix. In the LPN model, Be droplets were assumed to nucleate in the liquid ahead of the solid—liquid interface, but no justification for this was given. Here we present a model which considers the geometric constraints (imposed by proximity to the interface) on the number of solute atoms available to form a nucleus. Calculations based on this model predict that nucleation of second-phase particles can be most likely a short distance ahead of the interface in immiscible binary systems such as AlBe. As part of the nucleation calculations, a semi-empirical method of calculating solid—liquid surface tensions in binary systems was developed, and is presented in the Appendix.

Poly-Si thin-film transistors (TFTs) have recently been introduced to commercial glass flat-panel displays. This letter presents a manufacturable process for fabricating poly-Si TFTs directly on plastic substrates that exceed TFT parameter requirements for active-matrix displays. Plastic sheets are laminated onto carrier wafers, to allow use of automated tools for manufacturing. In order to maintain adhesion through the whole process, the wafer temperature is kept below 105/spl deg/C. Laser crystallization is used to grow poly-Si, and a quarter-wavelength stack layer is deposited to protect plastic from the laser processing. In order to achieve state-of-the-art poly-Si TFTs on plastic, the gate oxide is optimized. Using a higher temperature anneal after delamination minimizes leakage currents.

Reactively sputtered from a W2B target, amorphous W-B-N thin films are investigated. The physical properties of the films, namely density, resistivity, crystallization behavior and reaction temperature with silicon, are given as functions of composition. Additionally, the films are assessed as diffusion barriers between silicon substrates and copper overlays. By I(V) measurements of shallow-junction diodes, a 100 nm W64B20N16 barrier prevents copper from reaching the silicon during an 800 °C, 30 min heat treatment in vacuum. W79B21 films are able to prevent diffusion into the diodes only up to 500 °C. High resolution transmission electron microscopy shows that W64B20N16 and W79B21 films are both marginally amorphous with local ordering of less than 1.5 nm.

A direct liquid connection system has been applied to the chemical vapor deposition of copper using the commercially available Cu(I) precursor (hfac)Cu(TMVS), where hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate and TMVS = trimethylvinyl-silane. Precursor delivery was enhanced through the use of a coinjection system wherein additional TMVS was mixed with tire copper precursor before injection into the vaporization chamber. The results reported here demonstrate the capability of depositing blanket cooper for high purity (on the order of 99.99% copper) and low resistivity (1.85 {+-} 0.1 {mu}{Omega}-cm). These copper films have been deposited at rates up to and exceeding 1,500 {angstrom}/min. The effects of temperature and carrier gas on deposition rate and resistivity are examined. The as-deposited films demonstrate and dependence of grain size with thickness and little structural or morphological change with annealing. This study suggests that liquid coinjection is an effective method for enhancing deposition rates and for producing high quality copper films from copper(I) precursors.

Extracellular single-unit recordings were obtained from 107 area postrema and 74 nucleus tractus solitarius neurons in sodium pentobarbitol anaesthetized rats. Systemic administration of vasopressin (1–10 ng) decreased the firing frequency of 45.8% of area postrema neurons and 58.1% of nucleus tractus solitarius neurons tested while the firing frequency of 38.3% of area postrema neurons and 21.6% of nucleus tractus solitarius neurons was increased by this peptide. To determine whether these neurons were specifically influcenced by vasopressin or the accompanying pressor response, the effects of α-adrenergic agonists on neuronal activity were also determined. Cells that responded similarly to vasopressin and the change in blood pressure elicited by a-adrenergic agonists were classified as “blood pressure-sensitive”, whereas those neurons that responded differently to both agents were classified as “vasopressin-sensitive” neurons. The majority (85.2%) of area postrema cells that decreased firing frequency in response to vasopressin were determined to be “vasopressin-sensitive”, while 68.8% of area postrema neurons responding to vasopressin with increases in firing frequency were classified as “blood pressure-sensitive”. In contrast, 78.6% of nucleus tractus solitarius neurons that decreased firing frequency in response to vasopressin and 55.5% of those that increased firing frequency were classified as “blood pressure-sensitive” neurons. To determine whether the actions of vasopressin in the area postrema were mediated by V1 receptors the effect of vasopressin after V1 receptor blockade was examined in seven “vasopressin-sensitive” area postrema neurons. All seven neurons tested showed no response to vasopressin after such V1 receptor blockade. These data suggest that there exists a population of area postrema neurons specifically responsive to circulating vasopressin as a result of actions of this peptide at V1 receptors. They also implicate these neurons in the physiological mechanisms through which circulating vasopressin acts in the area postrema to influence baroreceptor reflex sensitivity.

High electron mobility transistors (HEMTs) with single-quantum-well active layers composed of pseudomorphic InGaAs on GaAs and InP substrates have yielded substantial performance enhancements relative to their lattice-matched equivalents. The higher cut-off frequencies possessed by these devices have enabled new applications to be realized in the millimeter wave spectrum which are not feasible with lattice-matched HEMTs. Also, the devices are beginning to displace GaAs field effect transistors in the microwave spectrum as a result of higher gain and power-added efficiency inherent to the pseudomorphic devices. These developments in transistors and parallel developments in other strained layer material systems and devices have been paced by a resurgence in research and development in the materials science and engineering of strained epitaxial layers.

Vibrational spectra are reported and assigned for the planar D 3 h symmetry cyclopropenium cations [C 3 X 3 ] + (X= Cl, Br or I) from investigations of the compounds C 3 Cl 3 AlCl 4 , C 3 Cl 3 GaCl 4 , C 3 Cl 3 FeCl 4 , C 3 Cl 3 SbCl 6 , C 3 Br 3 AlBr 4 and C 3 l 4 , using conventional infrared and Raman spectroscopy and Fourier transform Raman spectroscopy. The symmetric C—X stretching modes of [C 3 X 3 ] + occur at 458, 269 and 180 cm −1 and the ring-breathing modes at 1790, 1732 and ca . 1650 cm −1 in [C 3 Cl 3 ] + , [C 3 Br 3 ] + and [C 3 I 3 ] + , respectively. A normal coordinate calculation is performed for [C 3 Cl 3 ] + .

We present the design of several wideband, millimeter-wave, MMIC, medium power amplifiers using a newly developed high-power, high-yield, 70 nm gate-length GaAs MMIC pHEMT process. These amplifiers cover a range of about 65–125 GHz, and were designed for the purpose of driving sub-millimeter wave multipliers in the local oscillator subsystem of the Atacama Large Millimeter Array (ALMA) radio telescope. The highest-frequency amplifiers in this chipset have average output power density over wide bandwidth of 200 mW/mm, representing the best performance to date for GaAs pHEMTs above W-Band.

This paper reports the scaling behaviors of 25-nm asymmetrically recessed metamorphic high electron-mobility transistors. By employing an optimized epitaxial design and an asymmetric gate recess, excellent off-state and on-state breakdown voltages have been have been demonstrated for 25-nm high-performance metamorphic high electronmobility transistors. The results reported herein demonstrate that these devices are excellent candidates for ultra-high-frequency power applications.

A Q-band MMIC power amplifier has been designed, processed, and measured with first pass success. Design parameters include 20 dBm power, 25 dB gain, 40 % PAE, input return loss of 10 dB and output return loss of 6 dB across 43.5 to 45.5 GHz. The MMIC design is based on the BAE Systems 0.1 μm MHEMT device, which has high gain and excellent PAE. The two-stage amplifier uses a 2-finger, 75 μm unit gate width, 0.1 μm gate length MHEMT device for the first stage and two 4-finger, 75 μm unit gate width, 0.1 μm gate length MHEMT devices for the output stage. Complete stabilization for both the even and odd mode is provided using feedback and resistors in critical locations of the circuit. The first stage is optimized for gain while the output stage is optimized for power and power-added efficiency (PAE). The complete MMIC amplifier measures 3.5 mm × 1.7 mm complete with dc blocks and dc biasing elements. Measured performance includes record high PAE of 46 % at 44.5 GHz, 24 dB small-signal gain, 1 dB compressed power of 18 dBm, and 3-dB compressed power of 20.5 dBm across the 43.5 to 45.5 GHz frequency band.

Les compositions antitranspiration reposent habituellement sur des principes actifs a base d'aluminium pour reduire la sudation. Le titane est un metal physiologiquement inoffensif, et les chelates du metal titane peuvent induire un blocage physique superficiel des pores pour donner une propriete antitranspiration efficace a partir de divers types de produits. Les chelates du metal titane peuvent etre formes a partir d'alkoxydes de titane et d'acides organiques. Les avis divergent quant a la structure du sel et, dans le cas du lactate d'ammonium et de titane partiellement neutralise (ATL), on a trouve des signes de divers ligands lies par des liaisons de forces differentes lors des differentes etapes de l'hydrolyse. On pense que l'aluminium fonctionne par diffusion le long du canal pour mener a l'antitranspiration via neutralisation jusqu'a obstruction par un gel polymerique relativement superficiel. L'ATL imite les sels d'aluminium classiques dans la mesure ou il s'agit principalement d'un principe actif antitranspiration topique, une peau traitee a l'ATL revenant a des schemas normaux de transpiration apres quelques pelages. Sous conditions de pH acide et presque neutre, le principe actif ATL, est relativement stable vis-a-vis de l'hydrolyse et peut etre formule en des compositions topiques soit en solution aqueuse du principe actif soit comme poudre libre dans des systemes anhydres. Lors de l'evaluation par une technique de test de l'activite in vitro qui renseigne sur le comportement in vivo, l'ATL agit comme un antitranspirant efficace.

In a double-blind multicentre study to compare pirenzepine with placebo in non-ulcer dyspepsia, 71 patients were randomized to receive 50 mg pirenzepine or placebo given orally twice daily for 4 weeks. The trial was not completed by five patients in the pirenzepine group and six in the placebo group. There were no significant differences between the groups in respect to changes in total symptoms (upper abdominal pain, nausea and vomiting, early satiety and postprandial bloating, eructation and pyrosis) scores and outcome, although 27/35 (77%) patients receiving pirenzepine were cured or improved compared with 22/36 (61%) receiving the placebo. Adverse effects were reported by 13 (37%) patients treated with pirenzepine and by six (17%) treated with placebo, seven withdrawing due to adverse effects.

Very low-noise 0.15- mu m gate-length W-band In/sub 0.52/Al/sub 0.48/As/In/sub 0.53/Ga/sub 0.47/As/In/sub 0.52/Al/sub 0.48/As/InP lattice-matched HEMTs are discussed. A maximum extrinsic transconductance of 1300 mS/mm has been measured for the device. At 18 GHz, a noise figure of 0.3 dB with an associated gain of 17.2 dB was measured. The device also exhibited a minimum noise figure of 1.4 dB with 6.6-dB associated gain at 93 GHz. A maximum available gain of 12.6 dB at 95 GHz, corresponding to a maximum frequency of oscillation, f/sub max/, of 405 GHz (-6-dB/octave extrapolation) in the device was measured. These are the best device results yet reported. These results clearly demonstrate the potential of the InP-based HEMTs for low-noise applications, at least up to 100 GHz. >

Small-animal imaging has emerged as a powerful technique to determine the pharmacokinetics and molecular effects of new drugs. Computer tomography (CT), magnetic resonance imaging (MRI), optical, single photon emission computed tomography (SPECT), and positron emission tomography (PET) can all be used to study these compounds or their effects directly. The methods all have varying sensitivities and resolutions and can be used to track events down to the molecular level. Around six orders of magnitude separate cellular and molecular events. Cell radii are around 10−5 m, whereas a small-molecular-weight compound (1 kDa) will have a molecular radius of around 10−10 m. Although MRI can have a resolution of below 10−4 m, the sensitivity of magnetic resonance spectroscopy is quite poor, at 10−4 molar. Conversely, PET and SPECT have lower resolutions of around 10−3 m, but the sensitivities are down to 10−12 molar and depend on the specific activity of the tracer used. Small-animal imaging is a valuable tool to investigate new drugs and validate their potential in vivo. CT and MRI are good methods for anatomical and functional imaging, but cannot be reliably used for molecular imaging since they require potentially pharmacologically active doses of drugs. Optical methods of imaging can be performed at the tracer level using bioluminescence and fluorescent imaging techniques, but they can only offer planar images which cannot give quantitative data. Small-animal imaging with PET and SPECT permits the non-invasive study of novel drugs as well as their effects in animals over substantial periods of time. The methods are directly transferable into the clinic and offer a rapid and cost effective way of developing new therapeutic strategies.

Nonhydrogenated, n-channel, low-temperature-processed, single-crystal Si thin-film transistors (TFTs) have been fabricated on Si thin films prepared via sequential lateral solidification (SLS). The device characteristics of the resulting SLS TFTs exhibit properties and a level of performance that are superior to polycrystalline Si-based TFTs and are comparable to similar devices fabricated on silicon-on-insulator (SOI) substrates or bulk-Si wafers. We attribute these high-performance device characteristics to the absence of high-angle grain-boundaries within the active channel portion of the TFTs.

Spinal shock is the loss of muscle tone and segmental spinal reflexes that develops caudal to a severe spinal cord injury. Although little recognized in the veterinary literature, spinal shock occurs in animals and is important in both accurate lesion localization and case management. In this review, we consider why spinal shock occurs and discuss the subsequent physiologic alterations, including the development of reflex hyperactivity. We also discuss differences in the expression of spinal shock between species and suggest why recovery of reflexes is relatively rapid in animals compared with humans. Finally, the implications for clinicians dealing with animals in the period immediately after severe spinal injury are considered.

The specific scientific tasks addressed in the July 1990 Gulf Stream (GS) experiment were the following: (1) Kelvin wake behavior across fronts at various ship speeds, (2) the physics of temperature front/radar cross section (RCS) mismatch, (3) wave-current interactions in curvature fronts, and (4) the hydrodynamic structure and origin of synthetic-aperture-radar (SAR) slick-like features. Overall, the GS Experiment was most successful, and about 60 percent of the planned data was collected. On-going efforts concentrate on the analysis and interpretation of the data. An overview of the experiment and preliminary results of the data analysis are given.

A free-drifting buoy has been designed which incorporates an array of capacitance wave gauges, an anemometer , compass, and a vertical accelerometer. The buoy is intended to drift free of the influence of an attending ship and collect and log high frequency wave data for verification of radar remotely sensed imagery. Data collected is used to derive energy directional wave spectra for wavelengths between 10 and 100 cm and wave slope statistics for wave scales larger than 10

Poly-Si Thin-Film Transistors (TFTs) are currently used in commercial active-matrix displays. They provide superior performance with respect to their amorphous silicon counterparts and allow integration of driving electronics directly on the display glass plates.For several applications, it can be desirable to have active-matrix displays made on flexible substrates. However, a direct application of a standard TFT process to plastic substrates is not in general possible, mostly because of temperature limits and related dimensional stability issues. In addition, standard flat-panel manufacturing tools are not capable of automatically handling non-rigid floppy substrates.Therefore, a new process has to be developed, compatible with a suitable way of handling plastic substrates. A process was developed in which plastic sheets are laminated on glass carrier wafers and run through all the automated tools. A low-temperature process using excimer laser annealing is developed and optimized. High-quality TFT backplanes are manufactured with a pixel layout designed for active-matrix OLED (AMOLED) displays. Field-effect mobility in excess of 70 cm2Vs on p-channel TFTs are achieved, together with leakage currents lower than 2 pA per micron gate width.Challenges include low-temperature gate dielectric development, reduction of intrinsic film stress, protection of plastic from laser damage, and contact formation. Solutions to these challenges are discussed and TFT transfer characteristics on glass and plastic substrates are presented. Finally, images from prototype monochrome AMOLED displays are presented, with 64 × 64 pixels and 80-dpi resolution.

We have developed 0.1-/spl mu/m gate-length InAlAs-InGaAs-InP power HEMT's with record efficiency and power gain at 94 GHz. A 200 /spl mu/m gate-width device has produced 58 mW output power with 6.4 dB power gain and 33% power-added efficiency. The extrapolated f/sub max/ of 600 GHz is the highest reported to date for any transistor, and smaller, 30-/spl mu/m devices fabricated on the same wafer exhibit excellent noise figure (1.4 dB at 94 GHz), demonstrating the applicability of this technology to multifunction MMICs. >

We report the development of a V-band monolithic power amplifier based on 0.1 /spl mu/m gate-length pseudomorphic HEMT's. The two-stage amplifier has demonstrated record performance at 60 GHz on the first design pass: 272 mW output power with 9.4 dB power gain and 24% power-added efficiency. The amplifier was designed for high-reliability communications applications, with passivation, good linearity and excellent thermal properties, and has been fabricated on 3-in. wafers with high yield and excellent uniformity-on one typical wafer, consistency of MMIC output power is better than /spl plusmn/0.5 dB with an associated total yield through RF test of 58%. >

Quarter-micron InAlAs/InGaAs planar-doped HEMTs (high-electron-mobility transistors) lattice-matched to InP have exhibited state-of-the-art noise and gain performance at frequencies up to 94 GHz. Minimum noise figures of 0.5, 1.2, and 2.1 dB have been measured at 18, 60, and 94 GHz, respectively. Small signal gains as high as 15.4 and 12.0 dB have been obtained at 63 and 95 GHz, respectively. Using 0.25 mu m InP-based HEMTs, a V-band three-stage amplifier yields an average noise figure of 3.0 dB with a gain of 22.0 +or-0.2 dB from 60 to 65 GHz at W-band, a two-stage amplifier exhibits a noise figure of 4.5 dB with a gain of 10.2 dB at 90.4 GHz, and a three-stage amplifier shows a noise figure of 4.8 dB with a gain of 15.0 dB at 90.4 GHz. It is concluded that these results clearly show the great potential of InP-based HEMTs for high-performance millimeter-wave low-noise receiver applications. >

Doped-channel, 0.25- mu m-gate-length, InGaAs pseudomorphic HEMTs (high electron mobility transistors) have been developed which exhibit state-of-the-art power performance at millimeter-wave frequencies, with output power density of 0.93 W/mm and power-added efficiency of 41% at 44 GHz. Using these devices, two Q-band hybrid power amplifiers have been developed. A two-stage design has produced 108 mW output power gain with 9.5 dB and 26.5% power-added efficiency. A three-stage design produced 251 mW output power with 13.6 dB of gain and 26.8% power-added efficiency. The peak efficiency of the three-state amplifier was 31.3% when biased differently. The linear gain of these amplifiers was 12 and 20 dB respectively. It is concluded that these amplifiers are an attractive alternative for designers of future millimeter-wave transmitters. >

A 0.15- mu m-gate-length double-heterojunction pseudomorphic HEMT (high electron mobility transistor) that exhibits state-of-the-art power and noise performance is reported. Power results include record power-added efficiencies of 51%, 41% and 23% at 35, 60 and 94 GHz, respectively, and output powers of 139 mW at 60 GHz and 57 mW at 94 GHz. Measured minimum noise figures of 0.55 dB at 18 GHz and 1.8 dB at 60 GHz are reported. It is suggested that because of its demonstrated performance and continued rapid rate of improvement, the pseudomorphic HEMT should be the preferred transistor for a number of millimeter-wave applications, used either as a discrete device in high-performance hybrid amplifiers or integrated into GaAs-based MMICs (monolithic microwave integrated circuits). >

The authors report the development of short gate-length (0.15-0.25- mu m) HEMTs (high-electron-mobility transistors) with state-of-the-art noise and power performance. The three families of HEMTs-conventional GaAs/AlGaAs, pseudomorphic, and InP-based-are described and compared. The InP HEMTs offer the lowest noise figure: device noise figures of 0.3 dB at 18 GHz and 1.4 dB at 94 GHz have been measured, and multistage amplifiers with 1.7-dB noise figure at 62 GHz and 3.3 dB at 92 GHz are reported. Pseudomorphic HEMTs that exhibit the best power performance of any millimeter-wave transistor have been developed, with record output powers of 658, 125, and 57 mW at 35, 60, and 94 GHz, respectively, and power-added efficiency as high as 41% at 60 GHz. A 44-GHz pseudomorphic HEMT power amplifier has generated 0.25-W output power with 27% power-added efficiency and 14-dB power gain. Finally, the reliability of the various HEMT types is discussed. >

State-of-the-art high-electron-mobility-transistor (HEMT) devices have been fabricated on InAlAs/InGaAs/InP. Devices with 30- mu m and 50- mu m gate widths and 0.15- mu m gate length were fabricated using an all-electron-beam lithography process. After mesa formation, ohmic contacts were formed using a standard NiAuGe metallization. The contacts were annealed using a rapid thermal annealer. Typical ohmic contact resistance was approximately 0.13 Omega -mm. This is the same as the typical contact for the GaAs-based pseudomorphic HEMT result. Gates were defined using a trilayer resist scheme and recessed using a wet chemical etch to reach the desired channel current. A TiPtAu metallization forms the gate. The devices exhibited performance superior to most other low noise HEMT devices. It is found that the gate leakage current increases as recess depth increases. This current increase seems to degrade noise performance. >

Short-gate-length high-electron-mobility transistors (HEMTs) are reported that have exhibited state-of-the-art low-noise performance at millimeter-wave frequencies; minimum noise figure of 1.2 dB at 32 GHz and 1.8 dB at 60 GHz from 0.25- mu m HEMTs. At Ka-band, a two-stage low-noise amplifier has demonstrated an average noise figure of 2 dB from 26.5 GHz to 37 GHz with a gain of 17 dB at 32 GHz. At V-band, a two-stage amplifier yielded a noise figure of 3.2 dB at 61 GHz with flat gain 12.7*0.5 dB from 59 GHz to 65 GHz. These devices are described and the potential for their future improvement is discussed. >

The relative importance of f/sub t/ and f/sub max/ in millimeter-wave evaluation is discussed. Also presented is a study of the variation of C/sub gs/ (input capacitance), C/sub gd/ (gate-drain feedback capacitance), g/sub m/ (peak transconductance), and g/sub o/ (output conductance) with the distance, L/sub gd/, between the metal edge and the n/sup +/ cap layer on the drain side of the device in ultrashort-gate-length HEMT (high-electron-mobility transistors). For this study, a 0.15- mu m-gate-length, double-recess pseudomorphic HEMT was fabricated that exhibits a maximum frequency of oscillation, f/sub max/, of 350 GHz. This value is the highest f/sub max/ reported for any transistor. A very high C/sub gs//C/sub gd/ of 76 and a large voltage gain, g/sub m//g/sub o/ of 75 are observed in the device. These exceptional results are attained primarily by increasing L/sub gd/ to 2.3 times the gate length. >

High-performance InAlAs/InGaAs planar-doped HEMTs (high-electron-mobility transistors) lattice-matched to InP have been fabricated with a 0.25- mu m T-gate. A maximum extrinsic transconductance g/sub m/ of 900 mS/mm, corresponding to an intrinsic g/sub m/ of 1640 mS/mm, was obtained at room temperature. RF measurements at 18 GHz yielded a minimum noise figure of 0.5 dB with an associated gain of 15.2 dB and a maximum stable gain of 20.9 dB. At 58 GHz, the devices exhibited a 1.2-dB minimum noise figure with an 8.5-dB associated gain. At 63 GHz, a maximum available gain of 15.4 dB was measured for a single-stage amplifier. This value, extrapolated to -6 dB/octave, yielded a maximum frequency of oscillation f/sub max/ of 380 GHz, which is the highest f/sub max/ ever reported for any transistor. A three-stage HEMT amplifier exhibited an average noise figure of 3.0 dB with a gain of 22.0+or-0.2 dB from 60-65 GHz. >

The development of InGaAs pseudomorphic high-electron mobility transistors (HEMTs) with state-of-the-art power performance at millimeter-wave frequencies is reported. Results given include maximum power-added efficiencies of 44% at 35 GHz and 36% at 44 GHz, output power of 100 mW with 22% efficiency and 3-dB gain at 60 GHz, and output power of 9 mW at 94 GHz. Preliminary reliability data are presented, and prospects for further improvement in performance-the realization of multifinger HEMTs capable of higher output power and reduction of gate length to 0.1 mu m-are discussed. >

This paper reviews recent progress in the development of GaAs metamorphic HEMT (MHEMT) technology for microwave applications. Commercialization has begun, while efforts to further improve performance, manufacturability and reliability continue. We also report the first multi-watt MHEMT MMIC power amplifiers, demonstrating up to 3.2W output power and record power-added efficiency (PAE) at Ka-band.

A monolithic four-stage gain block amplifier based on 0.1 /spl mu/m InGaAs/GaAs PHEMT technology has been developed for wideband signal amplification covering the full W-band of 75 to 110 GHz. The development is part of an effort to build a low cost receiver module where full W-band instantaneous bandwidth is required. The measured gain averages about 22 dB while the noise figure ranges from 5.3 dB to 6.8 dB across the band. This is the first full W-band PHEMT MMIC amplifier to be reported, and its gain and noise figure performance compare favorably with other narrowband W-band circuits reported. Careful device and circuit characterization, repeatability of fabrication process, and design optimization played the main role in leading to the first-pass success of this MMIC. >