Effect of Ni on the Formation of ${hbox {Cu}}_{6}{hbox {Sn}}_{5}$ and ${hbox {Cu}}_{3}{hbox {Sn}}$ Intermetallics

In this paper, the effect of Ni on the formation of Cu₆Sn₅ and Cu₃Sn intermetallics between tin and (Cu,Ni) substrates has been studied by making use of the thermodynamic assessment of the Sn-Cu-Ni system. The driving forces for the diffusion of the elements in the intermetallic layers were calculated as a function of Ni content. Assuming constant mobilities of component atoms, the results suggest that the diffusion fluxes of all the components in the (Cu, Ni)₆Sn₅ layer increase with increasing content of dissolved Ni, while the Cu and Sn fluxes in the (Cu, Ni)₃Sn layer decrease. Therefore, the dissolution of Ni retards the growth of (Cu, Ni)₃Sn. When the Ni content of the (Cu,Ni) substrate is high enough, the intermetallic compound growth in the reaction zones is dominated by (Cu, Ni)₆Sn₅, and the (Cu, Ni)₃Sn layer disappears gradually. The small thickness of (Cu, Ni)₃Sn is associated with large difference between Sn and Cu fluxes in (Cu, Ni)₃Sn that encourages also the "Kirk-endall void" formation. In addition, the calculated driving forces suggest that the growth rate of (Cu, Ni)₆Sn₅ should further increase if (Cu, Ni)₃Sn disappears, resulting in an unusually thick (Cu, Ni)₆Sn₅ layer. The results of thermodynamic calculations supplemented with diffusion kinetic considerations are in good agreements with recent experimental observations.     

Characterization of $m$-Sequences of Lengths $2^{2k}-1$ and $2^{k}-1$ With Three-Valued Cross Correlation

Considered is the distribution of the cross correlation between in-sequences of length 2^2k -1, where m = 2k, and m-sequences of shorter length 2^k -1. New pairs of m -sequences with three-valued cross correlation are found and the complete correlation distribution is determined. Finally, we conjecture that there are no more cases with a three-valued cross correlation apart from the ones proven here.     

A 3$,times,$5-Gb/s Multilane Low-Power 0.18-$mu{hbox {m}}$ CMOS Pseudorandom Bit Sequence Generator

A low-power, three-lane, pseudorandom bit sequence (PRBS) generator has been fabricated in a 0.18-mum CMOS process to test a multilane multi-Gb/s transmitter that cancels far-end crosstalk. Although the proposed PRBS generator was designed to produce three uncorrelated 12-Gb/s PRBS sequences, measurement results included in this paper have been obtained at only 5 Gb/s due to test setup limitations. The prototype employs a CMOS latch optimized to operate at frequencies close to the of the process and a current-mode logic (CML) MUX with modified active inductor loads for better high-speed large-signal behavior. In order to reduce the power consumption, a quarter-clock rate linear feedback shift register (LFSR) core in a power-efficient parallel architecture has been implemented to minimize the use of power-hungry, high-speed circuitry. Further power reduction has been achieved through the clever partitioning of the system into static logic and CML. In addition, the prototype design produces three uncorrelated 12-Gb/s data streams from a single quarter-rate LFSR core, thereby amortizing the power across multiple channels which lowers the power per channel by 3 times. The total measured power consumption at 5 Gb/s is 131 mW per lane and the calculated figure of merit per lane is 0.84 pJ/bit, which is significantly better than previously published designs.     

Actively $Q$ -switched and Mode-Locked Diode-Pumped ${hbox {Nd:GdVO}}_{4}{hbox {--KTP}}$ Laser

By using a comparative simple configuration and a short cavity length, a diode-pumped actively Q -switched and mode-locked intracavity frequency doubled Nd:GdVO₄-KTP green laser with the modulation depth 100% was realized, from which the great average output power, the high efficiency were obtained and the mode-locked pulse inside the Q -switched pulse has a repetition rate of 476 MHz. Using the hyperbolic secant function methods and by considering the Gaussian distribution of the intracavity photon density, the influences of continuous pump rate, the upper state lifetime of the active medium and the turnoff time of the acousto-optic Q -switch, we proposed a developed rate equation model for actively Q -switched and mode-locked green lasers. With this developed model, the theoretical calculations are in good agreement with the experimental results and the width of the mode-locked green pulse is estimated to be about 185 ps.     

New Terahertz Laser Lines From $^{13}{hbox {CD}}_{3}{hbox {OH}}$ Pumped by Regular and Hot Bands ${hbox {CO}}_{2}$ Laser

We have used our new pulsed ${hbox {CO}}_{2}$ laser, operating both on regular and hot bands, to excite the $^{13}{hbox {CD}}_{3}{hbox {OH}}$ methanol isotopomer. This has lead to the observation of 13 new high-threshold far-infrared laser emissions (also identified as terahertz laser lines), with frequencies in the range between 24.11 and 102.56 cm$^{-1}$ (0.72–3.07 THz). The absorption transitions leading to these new FIR laser emissions have been located by observing the optoacoustic absorption spectra around the ${hbox {CO}}_{2}$ emissions. Here, we present these new far-infrared laser lines, characterized in wavelength, polarization, offset relative to the center of the pumping ${hbox {CO}}_{2}$ laser transition, relative intensity, and optimum operation pressure.      

A Single-Chip UHF RFID Reader in 0.18 $mu{hbox {m}}$ CMOS Process

A single-chip UHF RFID reader that integrates all building blocks—including an RF transceiver, IQ data converters, and a digital baseband—is implemented in a 0.18 $mu{hbox {m}}$ CMOS process. A high-linearity RX front-end and a low-phase-noise synthesizer are proposed to handle the large self-interferer, which is a key challenge in the reader RX design. Highly reconfigurable mixed-signal baseband architecture for channel-selection filtering is proposed to achieve power optimization for multi-protocol operation with different system dynamic ranges and data rates. The reader dissipates a maximum power of 276.4 mW when transmitting maximum output power of 10.4 dBm and receiving the tag's response of $-$70 dBm in the presence of $-$5 dBm self-interferer while occupying 18.3 ${hbox {mm}}^{2}$.      

Microwatt MOSLED Using ${hbox {SiO}}_{rm x}$ With Buried Si Nanocrystals on Si Nano-Pillar Array

Microwatt light emission from a metal-oxide-semiconductor light-emitting diode (MOSLED) made by using SiOx film with buried Si nanocrystals on Si nano-pillar array is demonstrated. The Si nano-pillar array obtained by drying the rapidly self-aggregated Ni nano-dot-masked Si substrate exhibit size, aspect ratio, and density of 30 nm, 10, and 2.8times10¹⁰ cm^-2, respectively. These high-aspect-ratio Si nano-pillar array helps to enhance the Fowler-Nordheim tunneling-based carrier injection and to facilitate the complete relaxation on total internal reflection, thus increasing the quantum efficiency by one order of magnitude and improving the light extraction from the nano-roughened device surface by three times at least. The light-emission intensity, turn-on current and power-current slope of the MOSLED are 0.2 mW/cm² , 20-30 muA, and 3plusmn0.5 mW/A, respectively. At a biased current of 400 muA, the highest external quantum efficiency is over 0.2% to obtain the maximum EL power of > 1 muW. Compared with the same device made on smooth Si substrate under a power conversion ratio of 1 times 10^-4 , such an output power performance is enhanced by at least one order of magnitude.     

Improved Sellmeier Equations and Phase-Matching Characteristics in Deep-Ultraviolet Region of ${hbox {KBe}}_{2}{hbox {BO}}_{3}{hbox {F}}_{2}$ Crystal

A 3.0-mm-thick KBe ₂BO₃F₂ (KBBF) crystal has been successfully grown and used to fabricate a right angle prism. Its refractive indices were accurately measured with a prism technique at seven wavelengths from 0.4047 to 0.6562 mum . Its phase-matching characteristics in deep-ultraviolet (UV) region were investigated. Using the measured indices and phase-matching angles from deep-UV to near infrared, improved Sellmeier equations for KBBF have been derived.     

High-Performance Continuous-Wave Operation of $lambda sim {hbox {4.6}}~mu{hbox {m}}$ Quantum-Cascade Lasers Above Room Temperature

We report the high-performance continuous-wave (CW) operation of 10-mum-wide quantum-cascade lasers (QCLs) emitting at lambda ~ 4.6mum, based on the GaInAs-AlInAs material without regrowth, in epilayer-up and -down bonding configurations. The operational characteristics of QCLs such as the maximum average power, peak output power, CW output power, and maximum CW operating temperature are investigated, depending on cavity length. Also, important device parameters, i.e., the waveguide loss, the transparency current density, the modal gain, and the internal quantum efficiency, are calculated from length-dependent results. For a high-reflectivity (HR) coated 4-mm-long cavity with epilayer-up bonding, the highest maximum average output power of 633 mW is measured at 65% duty cycle, with 469 mW still observed at 100%. The laser exhibits the maximum wall-plug efficiencies of 8.6% and 3.1% at 298 K, in pulsed and CW operatons, respectively. From 298 to 393 K, the temperature dependent threshold current density in pulsed operation shows a high characteristic temperature of 200 K. The use of an epilayer-down bonding further improves the device performance. A CW output power of 685 mW at 288 K is achieved for the 4-mm-long cavity. At 298 K, the output power of 590 mW, threshold current density of 1.52 kA/cm², and maximum wall-plug efficiency of 3.73% are obtained under CW mode, operating up to 363 K (90degC). For HR coated 3-mm-long cavities, laser characteristics across the same processed wafer show a good uniformity across the area of 21 cm², giving similar output powers, threshold current densities, and emission wavelengths. The CW beam full-width at half-maximum of far-field patterns are 25deg and 46deg for the parallel and the perpendicular directions, respectively.     

High Density and Low Leakage Current in $ hbox{TiO}_{2}$ MIM Capacitors Processed at 300 $^{circ} hbox{C}$

We report Ir/TiO₂/TaN metal-insulator-metal capacitors processed at only 300degC, which show a capacitance density of 28 fF/mum² and a leakage current of 3 times 10^-8 (25degC) or 6 times 10^-7 (125degC) A/cm² at -1 V. This performance is due to the combined effects of 300degC nanocrystallized high-kappa TiO₂, a high conduction band offset, and high work-function upper electrode. These devices show potential for integration in future very-large-scale-integration technologies.     

Reliability of Combined $k{hbox{-out-of-}}n$ and Consecutive $k_{c}{hbox{-out-of-}}n$ Systems of Markov Dependent Components

A combined $k{hbox{-out-of-}}n$ :$F(G)$ & consecutive $k_{c}{hbox{-out-of-}}n{hbox{:}}F(G)$ system fails (functions) iff at least $k$ components fail (function), or at least $k_{c}$ consecutive components fail (function). These models involve two common failure criteria, and can be used in various situations depending on the actual failure criteria involving consecutive components, or all components. Explicit formulas for the reliabilities of these systems are obtained for Markov dependent components using the distribution theory of runs. Some numerical results are also presented.      

A 40-MHz Double Differential-Pair CMOS OTA With $-{hbox{60-dB}}$ IM3

A configuration of a linearized operational transconductance amplifier (OTA) for low-voltage and high-frequency applications is proposed. By using double pseudodifferential pairs and the source-degeneration structure under nano-scale CMOS technology, the nonlinearity caused by short channel effect from a small feature size can be minimized. A robust common-mode control system is designed for input and output common-mode stability and thus reduces distortion caused b y common-mode voltage variation. Tuning ability can be achieved by using MOS transistors in the linear region. The linearity of the OTA is about -60-dB third-order inter-modulation (IM3) distortion for up to 0.9 V_pp at 40 MHz. This OTA was fabricated by the TSMC 180-nm deep n-well CMOS process. It occupies a small area of 15.1times10^-3 mm² and the power consumption is 9.5 mW under a 1.5-V supply voltage.     

A Tunable Pseudo-Differential OTA With $-78~{hbox {dB}}$ THD Consuming 1.25 mW

A novel linear tunable transconductor based on a combination of linearization techniques is presented. The input signal is transferred to the V-I conversion element by means of a high-speed feedback loop. Then, the linear V-I conversion is accomplished using quasi-floating-gate MOS transistors biased in the triode region. Finally, the absence of current mirrors in the signal path provides low sensitivity to transistor mismatch and reduces the harmonic distortion. The operational transconductance amplifier (OTA) was fabricated in a 0.5-mum CMOS technology with a single 3.3-V supply voltage. Experimental results show a total harmonic distortion of -78 dB at 1 MHz with 1-V_pp input signal. High linearity of the OTA is obtained over a two octave tuning range with only 1.25-mW power consumption.     

Fabrication of Self-Aligned Enhancement-Mode $ hbox{In}_{0.53}hbox{Ga}_{0.47}hbox{As}$ MOSFETs With $ hbox{TaN/HfO}_{2}hbox{/AlN}$ Gate Stack

In this letter, we report the fabrication and characterization of self-aligned inversion-type enhancement-mode In_0.53Ga_0.47As metal-oxide-semiconductor field-effect transistors (MOSFETs). The In_0.53Ga_0.47As surface was passivated by atomic layer deposition of a 2.5-nm-thick AIN interfacial layer. In_0.53Ga_0.47As MOS capacitors showed an excellent frequency dispersion behavior. A maximum drive current of 18.5 muA/mum was obtained at a gate overdrive of 2 V for a MOSFET device with a gate length of 20 mum. An I_on/_off ratio of 104, a positive threshold voltage of 0.15 V, and a subthreshold slope of ~165 mV/dec were extracted from the transfer characteristics. The interface-trap density is estimated to be ~7-8 times 10¹² cm^-2 ldr eV^-1 from the subthreshold characteristics of the MOSFET.     

Numerical Modeling of Diode-End-Pumped High-Power ${hbox {Er}}^{3+}$:YAG Lasers

A theoretical model is presented describing continuous-wave operation of diode-end-pumped Er³⁺ :YAG lasers. Implemented as a numerical computer model it takes into account the full spectral information of the pump and laser transitions as well as all important ionic levels, their Stark splitting, decay schemes, up-conversion processes, excited-state absorption and especially the thermal dependencies of these important parameters. The model is compared to experimental results with good agreement and predicts highly efficient operation of Er:YAG lasers even at high temperatures.     

22.7-dB Gain $-$19.7-dBm $ICP_{1{rm dB}}$ UWB CMOS LNA

A fully differential CMOS ultrawideband low-noise amplifier (LNA) is presented. The LNA has been realized in a standard 90-nm CMOS technology and consists of a common-gate stage and two subsequent common-source stages. The common-gate input stage realizes a wideband input impedance matching to the source impedance of the receiver (i.e., the antenna), whereas the two subsequent common-source stages provide a wideband gain by exploiting RLC tanks. The measurements have exhibited a transducer gain of 22.7 dB at 5.2 GHz, a 4.9-GHz-wide B _3dB, an input reflection coefficient lower than -10.5 dB, and an input-referred 1-dB compression point of -19.7 dBm, which are in excellent agreement with the postlayout simulation results, confirming the approach validity and the design robustness.     

Structure Effects on Resistive Switching of $ hbox{Al/TiO}_{x}/hbox{Al}$ Devices for RRAM Applications

Resistive switching characteristics are investigated for Al/TiO_x/Al devices, particularly for the structural effects in crossbar and via-hole-type devices. The via-hole structure shows more reliable switching characteristics than the crossbar structure, owing to the elimination of possible edge effects. The asymmetric switching behavior is analyzed with top Al/TiO_x, and bottom Al/TiO_x interfaces. A trap-controlled space-charge- limited-current model is proposed as a possible switching mechanism, and it is verified that switching mainly occurs on the top electrode/TiO_x, interface side.     

Blue-Enhanced PIN Finger Photodiodes in a 0.35-$mu{hbox {m}}$ SiGe BiCMOS Technology

Finger photodiodes in PIN technology are introduced to enhance the responsivity for blue and ultraviolet light. A thick low doped epitaxial layer results in high responsivity and high bandwidth also for red and near-infrared light. Results of PIN finger photodiodes are compared to that of PIN photodiodes for 10- and 15-mum epitaxial intrinsic layer thickness. The cathode finger structure results in a high responsivity of 0.20 A/W (quantum efficiency 61%) for 410-nm light and a bandwidth of 1.25 GHz for 10- mum epi thickness at a reverse bias voltage of 3 V. The rise and fall times with an epitaxial layer thickness of 15 mum are below 1 ns for the wavelength range from 410 to 785 nm.     

$Ka$-Band Low-Loss and High-Isolation Switch Design in 0.13-$mu{hbox {m}}$ CMOS

This paper presents designs and measurements of Ka-band single-pole single-throw (SPST) and single-pole double-throw (SPDT) 0.13-CMOS switches. Designs based on series and shunt switches on low and high substrate resistance networks are presented. It is found that the shunt switch and the series switch with a high substrate resistance network have a lower insertion loss than a standard designs. The shunt SPST switch shows an insertion loss of 1.0 dB and an isolation of 26 dB at >35 GHz. The series SPDT switch with a high substrate resistance network shows excellent performance with 2.2-dB insertion loss and isolation at 35 GHz, and this is achieved using two parallel resonant networks. The series-shunt SPDT switch using deep n-well nMOS transistors for a high substrate resistance network results in an insertion loss and isolation of 2.6 and 27 dB, respectively, at 35 GHz. For series switches, the input 1-dB compression point (1P₁) can be significantly increased to with the use of a high substrate resistance design. In contrast, of shunt switches is limited by the self-biasing effect to 12 dBm independent of the substrate resistance network. The paper shows that, with good design, several 0.13- CMOS designs can be used for state-of-the-art switches at 26-40 GHz.