Single-photon avalanche diode fabricated in standard 55†nm bipolar-CMOS-DMOS technology with sub-20†V breakdown voltage.

This paper presents a single-photon avalanche diode (SPAD) in 55 nm bipolar-CMOS-DMOS (BCD) technology. In order to realize a SPAD having sub-20 V breakdown voltage for mobile applications while preventing high tunneling noise, a high-voltage N-well available in BCD is utilized to implement the avalanche multiplication region. The resulting SPAD has a breakdown voltage of 18.4 V while achieving an excellent dark count rate of 4.4 cps/µm2 at the excess bias voltage of 7 V in spite of the advanced technology node. At the same time, the device achieves a high peak photon detection probability (PDP) of 70.1% at 450 nm thanks to the high and uniform E-field. Its PDP values at 850 and 940 nm, wavelengths of interest for 3D ranging applications reach 7.2 and 3.1%, respectively, with the use of deep N-well. The timing jitter of the SPAD, full width at half maximum (FWHM), is 91 ps at 850 nm. It is expected that the presented SPAD enables cost-effective time-of-flight and LiDAR sensors with the advanced standard technology for many mobile applications.

Noise optimization of single-photon avalanche diodes fabricated in 110 nm CMOS image sensor technology.

This paper presents the effect of shallow trench isolation (STI) on the dark count rate (DCR) and after-pulsing probability (APP) of deep-junction-based single-photon avalanche diodes (SPADs). Two different SPADs were fabricated in 110 nm CMOS image sensor technology, one with STI and the other without STI between its anode and cathode. With TCAD simulations and measurements, we have clearly demonstrated that the SPAD without STI enables a dramatic decrease in DCR by more than three orders of magnitude without suffering from the lateral leakage current between the anode and cathode. By excluding the STI from the device, the proposed SPAD also achieves a negligible APP while the SPAD with STI shows a very high APP of 92%. Thanks to the low-noise performance, the proposed SPAD becomes operable with higher excess bias voltage so that it achieves good photon detection probability, 58.3% at 500 nm and 3% at 940 nm, and timing jitter, 71 ps full width at half maximum at 670 nm, when the reverse bias voltage is 17 V.

Si photonic-electronic monolithically integrated optical receiver with a built-in temperature-controlled wavelength filter.

We present a Si photonic-electronic integrated ring-resonator based optical receiver that contains a temperature-controlled ring-resonator filter (RRF), a Ge photodetector, and receiver circuits in a single chip. The temperature controller automatically determines the RRF temperature at which the maximum transmission of the desired WDM signal is achieved and maintains this condition against any temperature or input wavelength fluctuation. This Si photonic-electronic integrated circuit is realized with 0.25-µm photonic BiCMOS technology, and its operation is successfully confirmed with measurement.

A case of SFTS coinfected with E. coli bacteremia.

BACKGROUND: Severe fever thrombocytopenia syndrome virus (SFTSV) is the causative agent of severe fever thrombocytopenia syndrome (SFTS). SFTS is an emerging infectious disease, characterized by high fever, gastrointestinal symptoms, leukopenia, thrombocytopenia, and a high mortality rate. Until now, little importance has been given to the association of SFTS with leukocytosis and bacterial co-infection. CASE PRESENTATION: A 51-year old man visited our hospital with fever and low blood pressure. He was a farmer by occupation and often worked outdoors. He had a Foley catheter inserted due to severe BPH. Laboratory tests revealed thrombocytopenia, elevated liver function, and elevated CRP levels. He had marked leukocytosis, proteinuria, hematuria, and conjunctival hemorrhage. Initially, we thought that the patient was suffering from hemorrhagic fever with renal syndrome (HFRS). However, we confirmed SFTS through PCR and increasing antibody titer. However, his blood culture also indicated E. coli infection. CONCLUSION: SFTS displays characteristics of fever, thrombocytopenia, elevated liver function, and leukocytopenia. We described a case of SFTS with leukocytosis due to coinfection with E. coli. Since patients with SFTS usually have leukocytopenia, SFTS patients with leukocytosis are necessarily evaluated for other causes of leukocytosis. Here, we report the first case of an SFTS with concurrent E. coli bacteremia.

Numerical analysis on a viewing angle enhancement of a digital hologram by attaching a pixelated random phase mask.

In a digital hologram, the maximum viewing angle of a computer-generated hologram (CGH) is limited by pixel pitch due to the diffraction grating equation. Since reducing pixel size of display panel is challenging and costly, we propose a method to expand the viewing angle of a digital hologram by attaching an aligned pixelated random phase mask (PRPM) onto the CGH pattern based on analysis of simulation results. By introducing a phase-averaging process to the widely used iterative Fourier transform algorithm, an optimized CGH pattern can be obtained in conjunction with a PRPM. Based on scalar diffraction theory, viewing angle enhancement characteristics were verified by comparing the perspective views of a two-plane hologram using a virtual eye model. In addition, we performed full electromagnetic simulations that included effects due to potential fabrication errors such as misalignment, thickness variation, and internal reflections and diffractions between the CGH and random mask patterns. From the simulation results, by attaching a 1.85 µm-sized pixel pitch PRPM to a 3.7 µm CGH, the viewing angle can be easily expanded almost identical to that of a CGH with 1.85 µm-pixel pitch.

Data-Driven Object Vehicle Estimation by Radar Accuracy Modeling with Weighted Interpolation.

For accurate object vehicle estimation using radar, there are two fundamental problems: measurement uncertainties in calculating an object's position with a virtual polygon box and latency due to commercial radar tracking algorithms. We present a data-driven object vehicle estimation scheme to solve measurement uncertainty and latency problems in radar systems. A radar accuracy model and latency coordination are proposed to reduce the tracking error. We first design data-driven radar accuracy models to improve the accuracy of estimation determined by the object vehicle's position. The proposed model solves the measurement uncertainty problem within a feasible set for error covariance. The latency coordination is developed by analyzing the position error according to the relative velocity. The position error by latency is stored in a feasible set for relative velocity, and the solution is calculated from the given relative velocity. Removing the measurement uncertainty and latency of the radar system allows for a weighted interpolation to be applied to estimate the position of the object vehicle. Our method is tested by a scenario-based estimation experiment to validate the usefulness of the proposed data-driven object vehicle estimation scheme. We confirm that the proposed estimation method produces improved performance over the conventional radar estimation and previous methods.

Leg length discrepancy, overgrowth, and associated risk factors after a pediatric tibial shaft fracture.

BACKGROUND: This study was performed to investigate leg length discrepancy (LLD), overgrowth, and associated risk factors after pediatric tibial shaft fractures. MATERIALS AND METHODS: This study included 103 patients younger than 14 years of age (mean age 7.1 years; 75 boys, 28 girls) with unilateral tibial shaft fracture and a minimum follow-up of 24 months. LLD was calculated as the difference between the lengths of the injured and uninjured limbs. Overgrowth was calculated by adding the fracture site shortening from the LLD. Risk factors were assessed in patients with LLD < 1 cm and ≥ 1 cm and overgrowth < 1 cm and ≥ 1 cm. RESULTS: Casting and titanium elastic nailing (TEN) were performed on 64 and 39 patients, respectively. The mean LLD and overgrowth were 5.6 and 6.4 mm, respectively. There were significant differences in sex (p = 0.018), age (p = 0.041), fibular involvement (p = 0.005), injury mechanism (p = 0.006), and treatment methods (p < 0.001) between patients with LLDs < 1 cm and ≥ 1 cm. There were significant differences in sex (p = 0.029), fibular involvement (p = 0.002), injury mechanism (p = 0.008), and treatment methods (p < 0.001) between patients with overgrowth < 1 cm and ≥ 1 cm. Sex and treatment methods were risk factors associated with LLD ≥ 1 cm and overgrowth ≥ 1 cm following pediatric tibial shaft fracture. The boys had a 7.4-fold higher risk of LLD ≥ 1 cm and 5.4-fold higher risk of overgrowth ≥ 1 cm than the girls. Patients who underwent TEN had a 4.3-fold higher risk of LLD ≥ 1 cm and 4.8-fold higher risk of overgrowth ≥ 1 cm than those treated by casting. CONCLUSIONS: Patients undergoing TEN showed greater LLD and overgrowth than those undergoing casting, with boys showing greater LLD and overgrowth than girls. Surgeons should consider the possibility of LLD and overgrowth after pediatric tibial shaft fractures, especially when performing TEN for boys. LEVEL OF EVIDENCE: Level III.

Prediction of Lower Eyelid Malpositioning After Surgical Correction of Orbital Fracture Using the Subciliary Approach Through the Canthal Area and Orbital Vector Analysis.

A subciliary incision has been widely used not only for blepharoplasty but also for facial fracture surgery. However, lower eyelid malpositioning is one of the most common complications after fracture surgery. A limited number of studies have been conducted on the relationships among evaluation of the canthal area, orbital vector analysis, and lower eyelid malpositioning following the subciliary approach for surgical repair of fractures. The primary goal of this study was to identify and analyze the possible risk factors, including incidence of lower eyelid malpositioning and orbital vector after surgical correction of the orbital fracture. A total of 241 cases of orbital fracture surgery was retrospectively reviewed. Data related to the patient and surgery were collected. Orbital vector and angle that reflects the vector, distance between soft tissue and bone in the lateral canthal area were measured for orbital vector analysis. The relationship between the prevalence of the malpositioning of the lower eyelid and each factor was statistically analyzed. The distance between the soft tissue and bone at the lateral canthal area was statistically significant (P = 0.031). The distance between the soft tissue and bone at lateral canthal area illustrates the lateral side or periorbital anatomical morphology. It could be inferred that patients with a negative orbital vector were relatively more vulnerable to scar formation or lower eyelid malpositioning caused by iatrogenic factors. Therefore, it could be analyzed as a risk factor to predict the malpositioning of the lower eyelid postoperatively.

Optimal Screw Fixation of Syndesmosis Using a Targeting Drill Guide: A Technical Note.

Optimal screw fixation of the syndesmosis is difficult. We introduce a novel technique using a targeting drill guide for centroidal screw fixation of a syndesmosis to ensure a reproducible and optimal screw trajectory for syndesmosis fixation. By using a drill guide for anterior cruciate ligament surgery and intraoperative fluoroscopy, syndesmosis fixation enables reproducible fixation along an individual centroidal axis.

Vestibular Disorders: Pearls and Pitfalls.

Dizziness and vertigo are symptoms that commonly lead patients to seek neurologic or emergency care. Because symptoms are often vague and imprecise, a systematic approach is essential. By categorizing vestibular disorders based on the timing, triggers, and duration of symptoms, as well as emphasizing focused ocular motor and vestibular examinations, the majority of vestibular diagnoses can be made at the bedside. This paper will discuss the pearls and pitfalls in the history and examination of the most common acute, episodic, and chronic vestibular disorders.

Active Region Formation of Nanoelectromechanical (NEM) Devices for Complementary-Metal-Oxide-Semiconductor-NEM Co-Integration.

Considering the isotropic release process for nanoelectromechanical (NEM) devices, defining the specific sacrificial layer of the inter-metal-dielectric (IMD), i.e., the active region only for NEM devices, is one of the most important issue for complementary-metal-oxide-semiconductor-NEM (CMOS-NEM) co-integrated circuits. In this paper, novel fabrication method to define the active region of NEM devices is proposed by forming the trenched mesa-shape pattern in the IMD and depositing aluminum oxide (Al2O3) protecting layer. By applying the proposed process, the void space for mechanical operation of NEM devices can be formed user-controllably without the damage and collapse of CMOS part located below the NEM part. The feasibility of the proposed process is verified by fabricating and measuring the proof-of-concept prototype consists of the aluminum (Al) interconnects, silicon dioxide (SiO2) IMD and NEM memory switches.

Compact Potential Model for Si1-xGex/Si Heterojunction Double-Gate Tunnel Field-Effect Transistors (TFETs).

In this manuscript, the compact potential model for double-gate (DG) Si1-xGex/Si heterojunction tunnel field-effect transistors (TFETs) is proposed by adopting several strategies to the previous model. Compared with the control model, the enhanced model can describe the effects of additional parameters such as electron permittivity and Si1-xGex affinity, doping dependent bandgap narrowing, temperature, built-in potential change due to degenerately doping condition and energy band off-sets. The model accuracy is examined by benchmarking against to the technology computeraided design (TCAD) device simulations in terms of electrostatic potential profiles, band diagrams and minimum tunneling barrier width (Wt, min). As a result, the enhanced model accurately describes Wt, min in various gate voltages with different Ge mole fractions and gate oxide thicknesses. The DG heterojunction TFETs are regarded as one of the most promising successors to metal-oxide-semiconductor FETs (MOSFETs) as ultra-low-power logic devices, due to their high compatibility with complementary MOS (CMOS)-based integrated circuits (ICs) in terms of structures, materials and fabrication processes. The proposed enhanced model is expected to contribute for examining the TFETs circuit operation as well as understanding device physics, in depth, to extend Moore's Law.

Reconstruction for Skull Base Defect Using Fat-Containing Perifascial Areolar Tissue.

Skull base reconstruction is a challenging task. The method depends on the anatomical complexity and size of the defect. We obtained tissue by harvesting fat-containing perifascial areolar tissue (PAT) for reconstruction of limited skull base defects and volume augmentation. We demonstrated the effective option for reconstruction of limited skull base defects and volume augmentation. From October 2013 to November 2015, 5 patients underwent operations using fat-containing PAT to fill the defect in skull base and/or perform volume replacement in the forehead. Perifascial areolar tissue with 5- to 10-mm fat thickness was harvested from the inguinal region. The fat-containing PAT was grafted to the defect contacting the vascularized wound bed. Patients were followed up in terms of their clinical symptoms and postoperative magnetic resonance imaging findings. Four patients were treated using fat-containing PAT after tumor resection. One patient was treated for a posttraumatic forehead depression deformity. The fat-containing PAT included 5- to 9-mm fat thickness in all cases. The mean size of grafted PAT was 65.6 cm (28-140 cm). The mean follow-up period was 18.6 months (12-31 months). There was no notable complication. There was no donor site morbidity. We can harvest PAT with fat easily and obtain the sufficient volume to treat the defect. It also could be used with other reconstructive method, such as a free flap or a regional flap to fill the left dead space. Therefore, fat-containing PAT could be additional options to reconstruction of skull base defect.

The temporal dynamics of the distractor in the global effect.

In the global effect, saccades are displaced towards a distractor if the latter is near to the target, an effect thought to reflect spatial averaging in neurons of the superior colliculus. The temporal dynamics of the global effect have not been well studied, however. We had twelve subjects perform horizontal saccades to a target in trials in which there were either no distractor or a distractor stimulus located 20° above or below the target. The distractor appeared either simultaneously with the target or preceded it by an interval of between 100 and 800 ms, and was either flashed for only 100 ms or remained visible until the subject responded with a saccade. Both flashed and persistent distractors reduced saccadic latency if they preceded target onset, indicating that subjects could use this cue to prepare saccades in advance. Saccadic endpoint was displaced towards a flashed distractor only if it was simultaneous with the target. However, persistent distractors produced a global effect for both simultaneous presentation and distractor-target intervals of 100 ms, but not for longer intervals. We conclude that the global effect requires of the distractor both a recent onset and persistence of the distractor, and that distractor-related activity decays rapidly within 300 ms.

Negative Capacitance in Organic/Ferroelectric Capacitor to Implement Steep Switching MOS Devices.

Because of the "Boltzmann tyranny" (i.e., the nonscalability of thermal voltage), a certain minimum gate voltage in metal-oxide-semiconductor (MOS) devices is required for a 10-fold increase in drain-to-source current. The subthreshold slope (SS) in MOS devices is, at best, 60 mV/decade at 300 K. Negative capacitance in organic/ferroelectric materials is proposed in order to address this physical limitation in MOS technology. Here, we experimentally demonstrate the steep switching behavior of a MOS device-that is, SS ∼ 18 mV/decade (much less than 60 mV/decade) at 300 K-by taking advantage of negative capacitance in a MOS gate stack. This negative capacitance, originating from the dynamics of the stored energy in a phase transition of a ferroelectric material, can achieve the step-up conversion of internal voltage (i.e., internal voltage amplification in a MOS device). With the aid of a series-connected negative capacitor as an assistive device, the surface potential in the MOS device becomes higher than the applied gate voltage, so that a SS of 18 mV/decade at 300 K is reliably observed.

Double bi-material cantilever structures for complex surface plasmon modulation.

A complex modulation structure of surface plasmon polaritons using double bi-material cantilevers is proposed. It is shown with numerical analysis that the thermally controlled mechanical actuation of double bi-material cantilevers can modulate the amplitude and phase of surface plasmon polaritons across a full complex modulation range independently and simultaneously. The complex modulation structures designed for visible wavelengths are presented and their multi-wavelength integration is discussed.

Verilog-A behavioral model for resonance-modulated silicon micro-ring modulator.

We present an accurate behavior model for Si micro-ring modulators (MRM) based on Verilog-A, a standard simulation tool for electronic system design. Our model describes the electrical characteristics of the Si MRM using an equivalent circuit and the optical characteristics based on the couple-mode theory. The accuracy of our model is confirmed by comparing simulation results of our behavior model with the measurement results of a fabricated Si MRM. With this behavior model, co-simulation of Si MRM and electronic driving circuits in the standard electronic design environment can be easily performed.

A fully-integrated 12.5-Gb/s 850-nm CMOS optical receiver based on a spatially-modulated avalanche photodetector.

We present a fully integrated 12.5-Gb/s optical receiver fabricated with standard 0.13-µm complementary metal-oxide-semiconductor (CMOS) technology for 850-nm optical interconnect applications. Our integrated optical receiver includes a newly proposed CMOS-compatible spatially-modulated avalanche photodetector, which provides larger photodetection bandwidth than previously reported CMOS-compatible photodetectors. The receiver also has high-speed CMOS circuits including transimpedance amplifier, DC-balanced buffer, equalizer, and limiting amplifier. With the fabricated optical receiver, detection of 12.5-Gb/s optical data is successfully achieved at 5.8 pJ/bit. Our receiver achieves the highest data rate ever reported for 850-nm integrated CMOS optical receivers.

SNR characteristics of 850-nm OEIC receiver with a silicon avalanche photodetector.

We investigate signal-to-noise ratio (SNR) characteristics of an 850-nm optoelectronic integrated circuit (OEIC) receiver fabricated with standard 0.25-µm SiGe bipolar complementary metal-oxide-semiconductor (BiCMOS) technology. The OEIC receiver is composed of a Si avalanche photodetector (APD) and BiCMOS analog circuits including a transimpedance amplifier with DC-balanced buffer, a tunable equalizer, a limiting amplifier, and an output buffer with 50-Ω loads. We measure APD SNR characteristics dependence on the reverse bias voltage as well as BiCMOS circuit noise characteristics. From these, we determine the SNR characteristics of the entire OEIC receiver, and finally, the results are verified with bit-error rate measurement.

Scale effects on stiction-induced release voltage shift of nano-electromechanical (NEM) memory cells.

In order to overcome the limits of conventional flash memory, nonvolatile nano-electromechanical (NEM) memory has been proposed. The release voltage shift of a NEM memory cell induced by beam stiction has been studied by using one-dimensional analytical model and three-dimensional finite element analysis (FEA) simulation. As the size of a NEM memory cell decreases, stiction effects become more severe because the spring force becomes weaker. The influence of NEM memory cell scaling on release voltage shift has been discussed. If all geometrical dimensions are scaled in proportion, which is called general scaling, release voltage shift becomes larger, and release voltage becomes smaller. Then, if release voltage shift becomes larger than release voltage as general scaling continues, NEM memory cells do not work due to the permanently pulled-in cantilever beam. In order to prevent this, it is necessary to reduce beam length aggressively compared with other dimension scaling or to introduce more elastic and less adhesive beam material than existing beam material.