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.     

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.      

Two-Pulse $C$–$V$ : A New Method for Characterizing Electron Traps in the Bulk of $ hbox{SiO}_{2}/hbox{high-}kappa$ Dielectric Stacks

$hbox{SiO}_{2}/hbox{high-}kappa$ dielectric stack is a candidate for replacing the conventional $hbox{SiO}_{2}$-based dielectric stacks for future Flash memory cells. Electron traps in the high-$ kappa$ layer can limit the memory retention via the trap-assisted tunneling, and there is a pressing need for their characterization. A new two-pulse $C$ –$V$ measurement technique is developed in this letter, which, for the first time, allows us to probe the discharge of electron traps throughout the $hbox{SiO}_{2}/hbox{high-}kappa$ stack. It complements the charge pumping technique, which can only probe near-interface traps. It is demonstrated that a large number of electron traps, indeed, exist in the bulk of high-$kappa$ layer. Bulk electron traps also have different discharge characteristics from those near the $hbox{SiO}_{2}/hbox{high-}kappa$ interface.      

High-Performance $hbox{In}_{0.7}hbox{Ga}_{0.3}hbox{As}$ -Channel MOSFETs With High-$kappa$ Gate Dielectrics and $alpha$-Si Passivation

Long and short buried-channel $hbox{In}_{0.7}hbox{Ga}_{0.3}hbox{As}$ MOSFETs with and without $alpha$-Si passivation are demonstrated. Devices with $alpha$-Si passivation show much higher transconductance and an effective peak mobility of 3810 $hbox{cm}^{2}/ hbox{V} cdot hbox{s}$. Short-channel MOSFETs with a gate length of 160 nm display a current of 825 $muhbox{A}/muhbox{m}$ at $V_{g} - V_{t} = hbox{1.6} hbox{V}$ and peak transconductance of 715 $muhbox{S}/muhbox{m}$. In addition, the virtual source velocity extracted from the short-channel devices is 1.4–1.7 times higher than that of Si MOSFETs. These results indicate that the high-performance $hbox{In}_{0.7}hbox{Ga}_{0.3} hbox{As}$-channel MOSFETs passivated by an $alpha$ -Si layer are promising candidates for advanced post-Si CMOS applications.      

Analytical Model of $I$– $V$ Characteristics of Arbitrarily Shallow p-n Junctions

For the first time, an analytical model of arbitrarily shallow p-n junctions is presented. Depending on the junction depth, electrical characteristics of ultrashallow p-n junctions can vary from the characteristics of standard Schottky diodes to standard deep p-n junctions. This model successfully unifies the standard Schottky and p-n diode expressions. In the crossover region, where the shallow doping region can be totally depleted, electrical characteristics phenomenologically substantially different from typical diode characteristics are predicted. These predictions and the accuracy of the presented model are evaluated by comparison with the MEDICI simulations. Furthermore, ultrashallow $hbox{n}^{+}$-p diodes were fabricated, and the anomalous behavior in the crossover regime was experimentally observed.      

Eigendecomposition of Images Correlated on $S^{1}$, $S^{2}$, and $SO(3)$ Using Spectral Theory

Eigendecomposition represents one computationally efficient approach for dealing with object detection and pose estimation, as well as other vision-based problems, and has been applied to sets of correlated images for this purpose. The major drawback in using eigendecomposition is the off line computational expense incurred by computing the desired subspace. This off line expense increases drastically as the number of correlated images becomes large (which is the case when doing fully general 3-D pose estimation). Previous work has shown that for data correlated on S ¹ , Fourier analysis can help reduce the computational burden of this off line expense. This paper presents a method for extending this technique to data correlated on S ² as well as SO(3) by sampling the sphere appropriately. An algorithm is then developed for reducing the off line computational burden associated with computing the eigenspace by exploiting the spectral information of this spherical data set using spherical harmonics and Wigner-D functions. Experimental results are presented to compare the proposed algorithm to the true eigendecomposition, as well as assess the computational savings.     

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.     

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.      

Optimal $ Sigma Delta$ Modulator Architectures for Fractional-$ {N}$ Frequency Synthesis

This paper presents a comparative study of $Sigma Delta$ modulators for use in fractional-$ {N}$ phase-locked loops. It proposes favorable modulator architectures while taking into consideration not only the quantization noise of the modulator but also other loop nonidealities such as the charge pump current mismatch that contributes to the degradation in the synthesized tone's phase noise. The proper choice of the modulator architecture is found to be dependent upon the extent of the nonideality, reference frequency, and loop bandwidth. Three modulator architectures are then proposed for low, medium, and high levels of nonidealities.      

The Performance of Acoustic-Optical $Q$-switched Mode-Locking 1.34 $mu$m Nd:GdVO$_{4}$ Laser

A diode-end-pumped $Q$ -switched mode-locking $hbox{Nd:GdVO}_{4}$ laser operating at 1.34 $mu{hbox {m}}$ with an acousto-optical (AO) Q-switch in a compact V-type cavity was realized in our experiment for the first time. When the AO Q-switch repetition rate was 10 kHz, the maximum average output power of 750 mW and the pulse energy of 75 $muhbox{J}$ were obtained at the maximum incident pump power of 9 W. The mode-locking modulation depth of about 100% was obtained at certain pump power over the threshold. The mode-locked pulse inside in the $Q$-switched pulse had a repetition rate of 341 MHz, and its average pulsewidth was estimated to be about 350 ps. A developed rate equation model for the $Q$ -switched and mode-locked lasers with an AO Q-switch were proposed by using the hyperbolic secant functional methods. The results of numerical calculations of the rate equations were in good agreement with the experimental results.      

Scaling Properties of $hbox{Ge}$ –$hbox{Si}_{x}hbox{Ge}_{1 - x}$ Core–Shell Nanowire Field-Effect Transistors

We demonstrate the fabrication of high-performance $hbox{Ge}$ –$hbox{Si}_{x}hbox{Ge}_{1 - x}$ core–shell nanowire (NW) field-effect transistors with highly doped source (S) and drain (D) and systematically investigate their scaling properties. Highly doped S and D regions are realized by low-energy boron implantation, which enables efficient carrier injection with a contact resistance much lower than the NW resistance. We extract key device parameters, such as intrinsic channel resistance, carrier mobility, effective channel length, and external contact resistance, as well as benchmark the device switching speed and on/off current ratio.      

Impacts of $hbox{N}_{2}$ and $hbox{NH}_{3}$ Plasma Surface Treatments on High-Performance LTPS-TFT With High-$kappa$ Gate Dielectric

Low-temperature polycrystalline-silicon thin-film transistors (LTPS-TFTs) with high- $kappa$ gate dielectrics and plasma surface treatments are demonstrated for the first time. Significant field-effect mobility $mu_{rm FE}$ improvements of $sim$86.0% and 112.5% are observed for LTPS-TFTs with $hbox{HfO}_{2}$ gate dielectric after $hbox{N}_{2}$ and $ hbox{NH}_{3}$ plasma surface treatments, respectively. In addition, the $hbox{N}_{2}$ and $ hbox{NH}_{3}$ plasma surface treatments can also reduce surface roughness scattering to enhance the field-effect mobility $mu_{rm FE}$ at high gate bias voltage $V_{G}$, resulting in 217.0% and 219.6% improvements in driving current, respectively. As a result, high-performance LTPS-TFT with low threshold voltage $V_{rm TH} sim hbox{0.33} hbox{V}$, excellent subthreshold swing S.S. $sim$0.156 V/decade, and high field-effect mobility $mu_{rm FE} sim hbox{62.02} hbox{cm}^{2}/hbox{V} cdot hbox{s}$ would be suitable for the application of system-on-panel.      

A $Q$– $f$ Droop Curve for Facilitating Islanding Detection of Inverter-Based Distributed Generation

This paper presents a new method for islanding detection of distributed generation (DG) inverter that relies on analyzing the reactive power versus frequency (Q-f) characteristic of the DG and the islanded load. The proposed method is based on equipping the DG interface with a Q-f droop curve that forces the DG to lose its stable operation once an islanding condition occurs. A simple passive islanding detection scheme that relies on frequency relays can then be used to detect the moment of islanding. The performance of the proposed method is evaluated under the IEEE 1547 and UL 1741 antiislanding test configuration. The studies reported in this paper are based on time-domain simulations in the power systems computer-aided design (PSCAD)/EMTDC environment. The results show that the proposed technique has negligible nondetection zone and is capable of accurately detecting islanding within the standard permissible detection times. In addition, the technique proves to be robust under multiple-DG operation.     

Improvement of On–Off-Current Ratio in $ hbox{TiO}_{rm x}$ Active-Channel TFTs Using $hbox{N}_{2} hbox{O}$ Plasma Treatment

Without sacrificing the on-current in the transfer characteristics, we have successfully reduced the off-current part by the optimal $hbox{N}_{2}hbox{O}$ plasma treatment to improve the on–off-current ratio in n-type titanium oxide $( hbox{TiO}_{rm x})$ active-channel thin-film transistors. While the high-power (275 W) $hbox{N}_{2}hbox{O}$ plasma treatment oxidizes the whole $hbox{TiO}_{rm x}$ channel and results in the reduction of both on- and off-current, the optimized low-power (150 W) process makes the selective oxidation of the top portion in the channel and reduces only the off-current significantly. Increase in on–off ratio by almost five orders of magnitude is achieved without change in on-current by using the presented method.      

A Comparative NBTI Study of $hbox{HfO}_{2}$, $hbox{HfSiO}_{x}$, and SiON p-MOSFETs Using UF-OTF $I_{rm DLIN}$ Technique

The time, temperature, and oxide-field dependence of negative-bias temperature instability is studied in $hbox{HfO}_{2}/hbox{TiN}$, $ hbox{HfSiO}_{x}/hbox{TiN}$, and SiON/poly-Si p-MOSFETs using ultrafast on-the-fly $I_{rm DLIN}$ technique capable of providing measured degradation from very short (approximately microseconds) to long stress time. Similar to rapid thermal nitrided oxide (RTNO) SiON, $hbox{HfO}_{2}$ devices show very high temperature-independent degradation at short (submilliseconds) stress time, not observed for plasma nitrided oxide (PNO) SiON and $hbox{HfSiO}_{x}$ devices. $hbox{HfSiO}_{x}$ shows lower overall degradation, higher long-time power-law exponent, field acceleration, and temperature activation as compared to $hbox{HfO}_{2}$, which are similar to the differences between PNO and RTNO SiON devices, respectively. The difference between $ hbox{HfSiO}_{x}$ and $hbox{HfO}_{2}$ can be attributed to differences in N density in the $hbox{SiO}_{2}$ IL of these devices.      

Density of States-Based DC $I$– $V$ Model of Amorphous Gallium–Indium–Zinc-Oxide Thin-Film Transistors

The density of states (DOS)-based DC I-V model of an amorphous gallium-indium-zinc oxide (a-GIZO) thin-film transistor (TFT) is proposed and demonstrated with self-consistent methodologies for extracting parameters. By combining the optical charge-pumping technique and the nonlinear relation between the surface potential (phiS) and gate voltage (V _GS), it is verified that the proposed DC model reproduces well both the measured V _GS-dependent mobility and the I _DS-V _GS characteristics. Finally, the extracted DOS parameters are N _TA = 4.4 times 10¹⁷ cm^-3 middot eV^-1, N _DA = 3 times 10¹⁵ cm^-3 middot eV^-1, kT _TA = 0.023 eV, kT _DGA = 1.5 eV, and EO = 1.8 eV, with the formulas of exponential tail states and Gaussian deep states.     

High-Performance Poly-Silicon TFTs Using a High-$k$ $hbox{PrTiO}_{3}$ Gate Dielectric

In this letter, a polycrystalline-silicon thin-film transistor (poly-Si TFT) with a high- $k$ $hbox{PrTiO}_{3}$ gate dielectric is proposed for the first time. Compared to TFTs with a $hbox{Pr}_{2}hbox{O}_{3}$ gate dielectric, the electrical characteristics of poly-Si TFTs with a $hbox{PrTiO}_{3}$ gate dielectric can be significantly improved, such as lower threshold voltage, smaller subthreshold swing, higher $I_{rm on}/I_{rm off}$ current ratio, and larger field-effect mobility, even without any hydrogenation treatment. These improvements can be attributed to the high gate capacitance density and low grain-boundary trap state. All of these results suggest that the poly-Si TFT with a high- $k$ $hbox{PrTiO}_{3}$ gate dielectric is a good candidate for high-speed and low-power display driving circuit applications in flat-panel displays.      

A Fault-Tolerant Manipulator Robot Based on ${{cal H}}_2$, ${{cal H}}_{infty }$, and Mixed ${{cal H}}_2/{{cal H}}_{infty }$ Markovian Controls

This paper develops a Markovian jump model to describe the fault occurrences in a manipulator robot of three joints. This model includes the changes of operation points and the probability that a fault occurs in an actuator. After a fault, the robot works as a manipulator with free joints. Based on the developed model, a comparative study among three Markovian controllers, H₂, H_infin, and mixed H₂/H_infin is presented, applied in an actual manipulator robot subject to one and two consecutive faults.     

Nonvolatile-Memory Characteristics of $hbox{AlO}^{-}$ -Implanted $hbox{Al}_{2}hbox{O}_{3}$

The nonvolatile-memory (NVM) characteristics of $hbox{AlO}^{-}$ -implanted $hbox{Al}_{2}hbox{O}_{3}$ structures are reported and shown to exhibit promising behaviors, including fast program/erase speeds and high-temperature data retention. Photoconductivity spectra show the existence of two dominant trap levels, located at around 2 and 4 eV below the conduction band minimum of $hbox{Al}_{2}hbox{O}_{3}$, and our calculations show that these levels are likely attributed to the defects in the $hbox{Al}_{2}hbox{O}_{3}$, such as the Al–O divacancy. The relative concentrations of these defects vary with the implant fluence and are shown to explain the NVM characteristics of the samples irradiated to different fluences.      

Improved Electrical Properties of Ge p-MOSFET With $ hbox{HfO}_{2}$ Gate Dielectric by Using $hbox{TaO}_{x} hbox{N}_{y}$ Interlayer

The electrical characteristics of germanium p-metal-oxide-semiconductor (p-MOS) capacitor and p-MOS field-effect transistor (FET) with a stack gate dielectric of HfO₂/TaOxNy are investigated. Experimental results show that MOS devices exhibit much lower gate leakage current than MOS devices with only HfO₂ as gate dielectric, good interface properties, good transistor characteristics, and about 1.7-fold hole-mobility enhancement as compared with conventional Si p-MOSFETs. These demonstrate that forming an ultrathin passivation layer of TaOxNy on germanium surface prior to deposition of high-k dielectrics can effectively suppress the growth of unstable GeOx, thus reducing interface states and increasing carrier mobility in the inversion channel of Ge-based transistors.