A New Method for Goodness-of-Fit Testing Based on Type-II Right Censored Samples

We present a simple method for testing goodness-of-fit based on Type-II right censored samples. Applying the property of order statistics due to Malmquist, we can transform any conventional Type-II right censored sample of size $r$ out of $n$ from a uniform distribution to a complete sample of size $r$ from a uniform distribution. This result is used to develop the proposed goodness-of-fit test procedure. The simulation studies reveal that the proposed approach provides as good or better overall power than the method of Michael & Schucany.      

$hbox{TiN/ZrO}_{2}$/Ti/Al Metal–Insulator–Metal Capacitors With Subnanometer CET Using ALD-Deposited $hbox{ZrO}_{2}$ for DRAM Applications

We provide the first report of the structural and electrical properties of $hbox{TiN/ZrO}_{2}$/Ti/Al metal–insulator–metal capacitor structures, where the $hbox{ZrO}_{2}$ thin film (7–8 nm) is deposited by ALD using the new zirconium precursor ZrD-04, also known as Bis(methylcyclopentadienyl) methoxymethyl. Measured capacitance–voltage ($C$– $V$) and current–voltage ( $I$–$V$) characteristics are reported for premetallization rapid thermal annealing (RTP) in $hbox{N}_{2}$ for 60 s at 400 $^{circ}hbox{C}$, 500 $^{circ}hbox{C}$, or 600 $^{ circ}hbox{C}$. For the RTP at 400 $^{circ}hbox{C}$ , we find very low leakage current densities on the order of nanoamperes per square centimeter at a gate voltage of 1 V and low capacitance equivalent thickness values of $sim$ 0.9 nm at a gate voltage of 0 V. The dielectric constant of $ hbox{ZrO}_{2}$ is 31 $pm$ 2 after RTP treatment at 400 $^{circ}hbox{C}$.      

A 125–1250 MHz Process-Independent Adaptive Bandwidth Spread Spectrum Clock Generator With Digital Controlled Self-Calibration

A process-independent adaptive bandwidth spread-spectrum clock generator (SSCG) with digitally controlled self-calibration techniques is proposed. By adaptively calibrating the VCO gain ($K_v$) and charge-pump (CP) current over C ($I_{CP}/C$), the SSCG can realize not only adaptive bandwidth but also process independence at each operating frequency. The innovative point is the adaptive bandwidth control using $K_v$ and $I_{CP}/C$ calibration. This control enabled a test chip to keep a sharp triangular SSC profile while operating over a wide frequency range (125 to 1250 $~$MHz). The variations of VCO gain and CP current are reduced to one third those of the conventional architecture. At 1250 $~$Mbps (625$~$MHz) the reduction of spectrum peak amplitude is 18.6$~$dB which is 2.3$~$dB better than the reduction obtained without calibration.      

An Analytical Method to Extract the Physical Parameters of a Solar Cell From Four Points on the Illuminated $J{-}V$ Curve

For a variety of solar cells, it is shown that the single exponential $J{-}V$ model parameters, namely—ideality factor $eta$ , parasitic series resistance $R_{s}$, parasitic shunt resistance $R_{rm sh}$, dark current $J_{0}$, and photogenerated current $J_{rm ph}$ can be extracted simultaneously from just four simple measurements of the bias points corresponding to $V_{rm oc}$, $sim!hbox{0.6}V_{rm oc}$, $J_{rm sc}$, and $sim! hbox{0.6}J_{rm sc}$ on the illuminated $J{-}V$ curve, using closed-form expressions. The extraction method avoids the measurements of the peak power point and any $dJ/dV$ (i.e., slope). The method is based on the power law $J{-}V$ model proposed recently by us.      

Q-Band pHEMT and mHEMT Subharmonic Gilbert Upconversion Mixers

This letter makes a comparison between Q-band 0.15 $mu{rm m}$ pseudomorphic high electron mobility transistor (pHEMT) and metamorphic high electron mobility transistor (mHEMT) stacked-LO subharmonic upconversion mixers in terms of gain, isolation and linearity. In general, a 0.15 $mu{rm m}$ mHEMT device has a higher transconductance and cutoff frequency than a 0.15 $mu{rm m}$ pHEMT does. Thus, the conversion gain of the mHEMT is higher than that of the pHEMT in the active Gilbert mixer design. The Q-band stacked-LO subharmonic upconversion mixers using the pHEMT and mHEMT technologies have conversion gain of $-$7.1 dB and $-$0.2 dB, respectively. The pHEMT upconversion mixer has an ${rm OIP}_{3}$ of $-$12 dBm and an ${rm OP}_{1 {rm dB}}$ of $-$24 dBm, while the mHEMT one shows a 4 dB improvement on linearity for the difference between the ${rm OIP}_{3}$ and ${rm OP}_{1 {rm dB}}$. Both the chip sizes are the same at 1.3 mm $times$ 0.9 mm.      

Evaluation of High-Temperature Absorption Coefficients of Ionized Gas Plasmas in Optical Fibers

The large absorption coefficient $alpha$ of a fiber core at high temperatures is closely related to the generation of a fiber fuse. When silica glass is heated to a temperature above 4500 K, it forms Si $^{+}$ and O $^{+}$ ions and electrons in the ionized gas plasma state. We estimate the $alpha$ value for the plasma in the fiber core at high temperatures. $alpha$ begins to increase at 3500 K, then increases rapidly with increasing temperature above 4000 K, reaching a value of $1times 10^{7}$ m$^{-1}$ at 6000 K. This value is about 300 times that necessary for initiating a fiber fuse.      

High-Density and Low-Leakage-Current MIM Capacitor Using Stacked $hbox{TiO}_{2}/hbox{ZrO}_{2}$ Insulators

We have fabricated high-$kappa hbox{Ni}/hbox{TiO}_{2}/hbox{ZrO}_{2}/ hbox{TiN}$ metal–insulator–metal (MIM) capacitors. A low leakage current of $hbox{8} times hbox{10}^{-8} hbox{A/cm}^{2}$ at 125 $^{circ}hbox{C}$ was obtained with a high 38- $hbox{fF}/muhbox{m}^{2}$ capacitance density and better than the $hbox{ZrO}_{2}$ MIM capacitors. The excellent device performance is due to the lower electric field in 9.5-nm-thick $hbox{TiO}_{2}/ hbox{ZrO}_{2}$ devices to decrease the leakage current and to a higher $kappa$ value of 58 for $ hbox{TiO}_{2}$ as compared with that of $hbox{ZrO}_{2}$ to preserve the high capacitance density.      

Analysis and Design of a CMOS UWB LNA With Dual- -Branch Wideband Input Matching Network

A wideband low-noise amplifier (LNA) based on the current-reused cascade configuration is proposed. The wideband input-impedance matching was achieved by taking advantage of the resistive shunt–shunt feedback in conjunction with a parallel LC load to make the input network equivalent to two parallel $RLC$-branches, i.e., a second-order wideband bandpass filter. Besides, both the inductive series- and shunt-peaking techniques are used for bandwidth extension. Theoretical analysis shows that both the frequency response of input matching and noise figure (NF) can be described by second-order functions with quality factors as parameters. The CMOS ultra-wideband LNA dissipates 10.34-mW power and achieves ${ S}_{11}$ below $-$8.6 dB, ${ S}_{22}$ below $-$10 dB, ${ S}_{12}$ below $-$26 dB, flat ${ S}_{21}$ of 12.26 $pm$ 0.63 dB, and flat NF of 4.24 $ pm$ 0.5 dB over the 3.1–10.6-GHz band of interest. Besides, good phase linearity property (group-delay variation is only $pm$22 ps across the whole band) is also achieved. The analytical, simulated, and measured results agree well with one another.      

Linear Systems, Sparse Solutions, and Sudoku

In this paper, we show that Sudoku puzzles can be formulated and solved as a sparse linear system of equations. We begin by showing that the Sudoku ruleset can be expressed as an underdetermined linear system: ${mmb{Ax}}={mmb b}$, where ${mmb A}$ is of size $mtimes n$ and $n>m$. We then prove that the Sudoku solution is the sparsest solution of ${mmb{Ax}}={mmb b}$, which can be obtained by $l_{0}$ norm minimization, i.e. $minlimits_{mmb x}Vert{mmb x}Vert_{0}$ s.t. ${mmb{Ax}}={mmb b}$. Instead of this minimization problem, inspired by the sparse representation literature, we solve the much simpler linear programming problem of minimizing the $l_{1}$ norm of ${mmb x}$, i.e. $minlimits_{mmb x}Vert{mmb x}Vert_{1}$ s.t. ${mmb{Ax}}={mmb b}$, and show numerically that this approach solves representative Sudoku puzzles.      

On the Mean Residual Life Function of Coherent Systems

We consider a coherent structure consisting of $n$ components having the property that if it is known that at most $r$ components $(r≪n)$ have failed, the system is still operating with probability 1. Some examples of the systems having this property are $(n-k+1)$-out-of- $n$, some parallel-series, and some series-parallel structures. Depending on the structure, and the number of active components of the coherent systems at time $t$ , the mean residual life function of the system is studied, by several authors. This paper investigates more properties of the mean residual life function of the coherent systems sharing the described property. We will show that, when the components of the system have increasing failure rate, the mean residual life function of the system is decreasing in time. Several examples, and illustrative graphs are also provided.      

Performance Mapping of Multijunction Solar Cells Based on Electroluminescence

Electroluminescence intensity maps of all three subcells of space grade III–V multijunction cells were obtained with the help of dedicated imaging sensors at a range of different injection currents. Solely based on these data, making use of the homogeneity of one subcell, the local diode properties of an equivalent single junction cell were obtained and converted into spatial distributions of open circuit voltage $(V_{rm oc})$ and current at a fixed operating voltage $(I_{rm op})$. On a sample basis of more than 200 cells, $V_{rm oc}$ and $I_{rm op}$ characterizing the entire cell were determined with an accuracy of $pm$3 mV and $pm$5 mA, respectively.      

Characterization and Modeling of RF-Performance $(f_{T})$ Fluctuation in MOSFETs

The fluctuation of RF performance (particularly for $f_{T}$ : cutoff frequency) in the transistors fabricated by 90-nm CMOS technology has been investigated. The modeling for $f_{T}$ fluctuation is well fitted with the measurement data within approximately 1% error. Low-$V_{t}$ transistors (fabricated by lower doping concentration in the channel) show higher $f_{T}$ fluctuation than normal transistors. Such a higher $f_{T}$ fluctuation results from $C_{rm gg}$ (total gate capacitance) variation rather than $g_{m}$ variation. More detailed analysis shows that $C_{rm gs} + C_{rm gb}$ (charges in the channel and the bulk) are predominant factors over $C_{rm gd}$ (charges in LDD/halo region) to determine $C_{rm gg}$ fluctuation.      

Pulsed $I_{d}$– $V_{g}$ Methodology and Its Application to Electron-Trapping Characterization and Defect Density Profiling

The pulsed current–voltage ($I$– $V$) measurement technique with pulse times ranging from $sim$17 ns to $sim$ 6 ms was employed to study the effect of fast transient charging on the threshold voltage shift $Delta V_{t}$ of MOSFETs. The extracted $Delta V_{t}$ values are found to be strongly dependent on the band bending of the dielectric stack defined by the high-$kappa$ and interfacial layer dielectric constants and thicknesses, as well as applied voltages. Various hafnium-based gate stacks were found to exhibit a similar trap density profile.      

10-GHz and 20-GHz Channel Spacing High-Resolution AWGs on InP

This letter reports on 10-GHz and 20-GHz channel-spacing arrayed waveguide gratings (AWGs) based on InP technology. The dimensions of the AWGs are 6.8$,times,$8.2 mm$^{2}$ and 5.0$,times,$6.0 mm$^{2}$, respectively, and the devices show crosstalk levels of $-$12 dB for the 10-GHz and $-$17 dB for the 20-GHz AWG without any compensation for the phase errors in the arrayed waveguides. The root-mean-square phase errors for the center arrayed waveguides were characterized by using an optical vector network analyzer, and are 18 $^{circ}$ for the 10-GHz AWG and 28$^{circ}$ for the 10-GHz AWG.      

A 100 MS/s 4 MHz Bandwidth 70 dB SNR $Delta Sigma$ ADC in 90 nm CMOS

This paper describes the results of an implementation of a high speed $Delta Sigma$ ADC in 90 nm CMOS process, which is developed for a direct-conversion digital TV receiver. The $Delta Sigma$ ADC is based on a switched-capacitor fourth-order single-loop $Delta Sigma$ modulator with a 4-bit quantizer. The ADC uses a triple sampling technique and a two-step summation scheme for low power and high speed operation. Also, a digital signal processing block, including a decimation filter, a channel selection filter and a digital programmable gain amplifier (PGA), is implemented in the same process. The decimation filter is based on a polyphase IIR filter with a decimation ratio of 5, while the channel selection filter is based on two path lattice wave digital IIR filter. The ADC achieves 69.95 dB SNR and 66.85 dB SNDR over a 4 MHz bandwidth with a sampling frequency of 100 MHz. The fabricated $Delta Sigma$ ADC and the digital signal processing block occupy 0.53$~$mm$^2$ and 0.09 mm$^{2}$, and consume 11.76 mW per channel.      

2 MHz AO $Q$ -switched ${rm TEM}_{00}$ Grazing Incidence Laser With 3 at.% Neodymium Doped Nd:YVO$_{4}$

We present a detailed experimental and theoretical study of the ultrahigh repetition rate AO $Q$ -switched ${rm TEM}_{00}$ grazing incidence laser. Up to 2.1 MHz $Q$-switching with ${rm TEM}_{00}$ output of 8.6 W and 2.2 MHz $Q$ -switching with multimode output of 10 W were achieved by using an acousto-optics $Q$ -switched grazing-incidence laser with optimum grazing-incidence angle and cavity configuration. The crystal was 3 at.% neodymium doped Nd:YVO$_{4}$ slab. The pulse duration at 2 MHz repetition rate was about 31 ns. The instabilities of pulse energy at 2 MHz repetition rate were less than ${pm}6.7hbox{%}$ with ${rm TEM}_{00}$ operation and ${pm}3.3hbox{%}$ with multimode operation respectively. The modeling of high repetition rate $Q$-switched operation is presented based on the rate equation, and with the solution of the modeling, higher pump power, smaller section area of laser mode, and larger stimulated emission cross section of the gain medium are beneficial to the $Q$-switched operation with ultrahigh repetition rate, which is in consistent with the experimental results.      

Cubic-Structured $hbox{HfO}_{2}$ With Optimized Doping of Lanthanum for Higher Dielectric Constant

It is demonstrated that $hbox{HfO}_{2}$ films can have much higher dielectric-constant values than the usual reported value of 20–24 by optimized incorporation of lanthanum element and crystallization to cubic structure. When $hbox{HfO}_{2}$ with 8% La is crystallized into cubic structure, the film exhibits the $kappa$ value of $sim$ 38 which is the highest among ever reported $hbox{HfO}_{2}$ -based high-$kappa$ dielectrics. The increased $kappa$ value of $ hbox{HfO}_{2}$ with 8% La enables the leakage current to be reduced more than one order of magnitude lower, compared to amorphous-phase $hbox{HfO}_{2}$ under the same electric field. The dependence of film thickness and annealing temperature on the cubic crystallization is also reported.      

Performance Improvement of N-Type $hbox{TiO}_{x}$ Active-Channel TFTs Grown by Low-Temperature Plasma-Enhanced ALD

We report on performance improvement of $n$-type oxide–semiconductor thin-film transistors (TFTs) based on $hbox{TiO}_{x}$ active channels grown at 250 $^{circ}hbox{C}$ by plasma-enhanced atomic layer deposition. TFTs with as-grown $hbox{TiO}_{x}$ films exhibited the saturation mobility $(mu_{rm sat})$ as high as 3.2 $hbox{cm}^{2}/hbox{V}cdothbox{s}$ but suffered from the low on–off ratio $(I_{rm ON}/I_{rm OFF})$ of $hbox{2.0} times hbox{10}^{2}$. $hbox{N}_{2}hbox{O}$ plasma treatment was then attempted to improve $I_{rm ON}/I_{rm OFF}$. Upon treatment, the $hbox{TiO}_{x}$ TFTs exhibited $I_{rm ON}/I_{rm OFF}$ of $hbox{4.7} times hbox{10}^{5}$ and $mu_{rm sat}$ of 1.64 $hbox{cm}^{2}/hbox{V}cdothbox{s}$, showing a much improved performance balance and, thus, demonstrating their potentials for a wide variety of applications such as backplane technology in active-matrix displays and radio-frequency identification tags.      

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.      

Positive Bias Temperature Instability (PBTI) Characteristics of Contact-Etch-Stop-Layer-Induced Local-Tensile-Strained $hbox{HfO}_{2}$ nMOSFET

The positive bias temperature instability (PBTI) characteristics of contact-etch-stop-layer (CESL)-strained $hbox{HfO}_{2}$ nMOSFET are thoroughly investigated. For the first time, the effects of CESL on an $hbox{HfO}_{2}$ dielectric are investigated for PBTI characteristics. A roughly 50% reduction of $V_{rm TH}$ shift can be achieved for the 300-nm CESL $hbox{HfO}_{2}$ nMOSFET after 1000-s PBTI stressing without obvious $ hbox{HfO}_{2}/hbox{Si}$ interface degradation, as demonstrated by the negligible charge pumping current increase ($≪$ 4%). In addition, the $hbox{HfO}_{2}$ film of CESL devices has a deeper trapping level (0.83 eV), indicating that most of the shallow traps (0.75 eV) in as-deposited $ hbox{HfO}_{2}$ film can be eliminated for CESL devices.