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These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal. [ABSTRACT FROM AUTHOR]

Presents the table of contents for this issue of the publication. [ABSTRACT FROM AUTHOR]

A novel comb-like-channel field-effect transistor (CombFET), which is the combination of the fin field-effect transistor (FinFET) and nanosheet FET (NshFET) geometries in the channel region, is proposed and evaluated numerically for the first time. Our simulations show that: 1) with the same footprint, CombFET ON-current is 43% higher than FinFET and 53% higher than gate-all-around FET (GAAFET) due to its larger effective channel width and relieved channel quantum confinement and 2) CombFETs have great advantages in performance optimization through surface orientation over FinFETs and NshFETs. Thanks to the unique structural design, CombFET can also be used to improve or eliminate the bending or adhesion effects between nanosheets/comb teeth. [ABSTRACT FROM AUTHOR]

Currently, the semiconductor industry requires test escape levels that approach the ppb level for application domains, such as automotive. Such quality levels, however, can only be reached if latent defects are screened out, as they have become the major bottleneck in analog and mixed-signal IC testing. Latent defects can be activated using accelerated aging, but this procedure has several drawbacks. Most notably, activation can move latent defects to the product lifetime that, otherwise, would not even have expressed themselves. Therefore, methods are needed that allow the detection of these defects without using activation. Developing such methods, however, has been hampered by the lack of compact latent defect models that allow simulating circuits affected by this type of defect. This article alleviates this problem by experimentally validating a recently presented compact model for latent defects and establishing the practical range of model values that should be used in simulations. The experiments performed on a 0.35- $\mu \text{m}$ technology consist of characterizing transistors containing latent defects that have been artificially introduced by etching pinholes in their gate. The measurement results corroborate that the drain current in transistors with defects increases with the area and depth of the defect, and that this behavior can be accurately modeled using an effective ${t}_{ox}$ value. [ABSTRACT FROM AUTHOR]

A very detailed investigation of high-speed silicon–germanium (SiGe) heterojunction bipolar transistors (HBTs) showed an underestimation of the measured peak cutoff frequency by simulations with a hydrodynamic (HD) model. It was speculated that this might be due to a breakdown of the HD approximation or unknown additional mechanical stress. We repeated those simulations with the more fundamental Boltzmann transport equation (BTE) based on the same device model (doping profiles, 2-D geometry, parasitics, and so on) and obtained almost similar results showing that this failure was not due to a breakdown of the HD approximation. Since additional uniaxial stress along the direction of the lateral base has been shown to increase the cutoff frequency, we investigated this effect. We found by 2-D device simulations that the increase in the peak cutoff frequency is rather small, and at high stress levels, it even decreases, if the uniaxial stress is applied homogenously. This is due to the reduction of the conductivity of the highly doped collector layer by the stress. If the stress is limited to the intrinsic transistor, the increase in the cutoff frequency is monotonic with growing stress. On the other hand, the collector current for a given base–emitter voltage also increases with stress leading to an overestimation of the collector current compared with the measurements. If this increase is corrected by a slight decrease in the germanium profile, the gain in the peak cutoff frequency is lost. Thus, the underestimation of the peak cutoff frequency cannot be explained by an additional homogeneous uniaxial stress in the intrinsic transistor. [ABSTRACT FROM AUTHOR]

The influence of SiO2 and SiNx capping layer on threshold voltage (${V}_{t}$) for FinFET with TiAl-based metal gate (MG) is studied. After metal gate-stack formation, SiNx capping is revealed to be able to serve as a new N source, resulting in the diffusion of N into the effective work function (EWF) TiNx layer. Correspondingly, the accumulation of N in the TiNx layer is demonstrated to be able to lower the EWF for both n- and p-FinFETs. Compared to SiO2 capping, SiNx capping can induce $\sim 100$ –150 mV ${V}_{t}$ lowering for short n- and p-FinFETs. No obvious ${V}_{t}$ shift is found for long-channel devices. [ABSTRACT FROM AUTHOR]

Gallium-oxide-based modulation-doped field-effect transistors (MODFETs) are theoretically investigated. In order to properly consider the electrical characteristics of the two-dimensional electron gases (2DEGs) in thin-channel devices, a coupled drift-diffusion (DD)/multisubband Boltzmann transport equation (MS-BTE) solver is implemented. Parameters adopted in the simulation are determined by referring to the experimental results of existing long-channel devices. The impact of the channel length, the channel thickness, the ungated region length, and contact resistance on the cutoff frequency is rigorously calculated. It is found that the cutoff frequency can have about 90 GHz with a contact resistance of $0.4~\Omega ~\cdot $ mm and a channel whose length and thickness are 30 and 5 nm, respectively. [ABSTRACT FROM AUTHOR]

This article proposes a new driving scheme based on an n-type low-temperature polycrystalline silicon (LTPS) four-transistor-two-capacitor (4T2C) pixel circuit to improve the quality of motion images of active matrix organic light-emitting diode (AMOLED) displays. The proposed driving scheme can prevent the effect of the lateral leakage current flowing through the OLED common layer by keeping the pixels in the upper and lower row lines in a nonemitting hold period during the program period. The simulation results show that all RGB colors maintain a shooting amount ratio (SAR) below 1% from the first frame when the image is switched from black to white, even for a concentration of the high p-doped hole transport layer (p-HTL). In addition, the parasitic capacitances of the 4T2C pixel circuit that causes OLED current errors are thoroughly analyzed for high luminance uniformity. A 1.5-in 326 pixels per inch (PPI) AMOLED panel based on the proposed driving scheme was fabricated. The results of our measurements show that the SARs of RGB colors are 0.8%, 0.2%, and 0.9%, respectively, and the average ${x}$ -coordinate shift of the color is 0.007 during the transition between black and white images due to the effective suppression of the lateral leakage current. Therefore, we demonstrate that the proposed driving scheme is suitable for AMOLED displays that require high-quality motion images. [ABSTRACT FROM AUTHOR]

We study the reduction in residual image in low-temperature poly-Si oxide (LTPO) thin-film transistor (TFT)-based flexible organic light-emitting diode (OLED) displays on polyimide (PI) substrate. Conventional voltage compensation circuit (seven TFTs plus one capacitor) is used with modification of driving and some switching TFTs. The measurement results on the threshold-voltage (${V}_{\text{TH}}$) shift and SPICE simulation data on the pixel circuits indicate that the residual image is due to the PI charging effect when a single-gate coplanar poly-Si TFT is used as driving one. It is shown here that adding a bottom electrode to the coplanar poly-Si driving TFT (D-TFT) eliminates the residual image by shielding the poly-Si active layer from the PI charging effect. [ABSTRACT FROM AUTHOR]

In this work, a novel one-transistor active pixel sensor (1T-APS) with adjustable self-adaptive sensitivity enabled by floating source/drain (S/D) is demonstrated on 22-nm fully depleted Si-on-insulator (FD-SOI) platform. Additional control gates (CGs) with floating S/Ds are incorporated into the sensor, which are parallel to the sensing gate (SG). For weak illumination, the CG channel keeps closed so that the photoresponse is only active for SG controlled region, resulting in high linear sensitivity, while the CG channel will automatically turn on when the illumination is strong enough. Correspondingly, the CG controlled region is connected with SG controlled region for photoresponse together, resulting in a relatively lower linear sensitivity. For very strong illumination, the 1T-APS will automatically switch to logarithmic response mode due to the activated virtual photodiode in the FD-SOI substrate. The sensitivity transition points in the linear–linear region and the linear–logarithmic region can be further adjusted by the bias of CG and back gate, respectively. The adjustable self-adaptive sensitivity indicates the great potential of the proposed 1T-APS for high-quality image sensing. [ABSTRACT FROM AUTHOR]

The extrinsic parasitics generally limit the modulation bandwidth of vertical cavity surface emitting lasers (VCSELs) for optical data links and interconnects. In this article, the extrinsic parasitics of 850-nm VCSELs are investigated by three different designs: oxide-only (design A), oxide-implant (design B), and oxide-implant with benzocyclobutene (BCB) (design C). The static and dynamic characteristics of all the designs with~7- $\mu \text{m}$ aperture are measured and compared. The maximum modulation bandwidth of design A is only about 12 GHz mainly limited by the large parasitic capacitances. With a proper proton implantation, a thick nonconducting layer is created inside the device with design B, which dramatically reduces the parasitic capacitances, and thus the bandwidth is increased to about 18 GHz. Based on design B, a 4- $\mu \text{m}$ -thick BCB layer with low dielectric constant is employed underneath the bond pad of design C to further reduce the pad capacitance, leading to the highest bandwidth about 24 GHz and the highest modulation current efficiency factor (MCEF) of 10.8 GHz/mA1/2. The microwave reflection coefficient (${S}_{{11}}$) parameters of the three designs are measured and compared. Results indicate that design C has the lowest parasitic capacitances and the highest modulation bandwidth, which is preferred for high-speed VCSELs to obtain good static and dynamic performance. [ABSTRACT FROM AUTHOR]

Lead-based organic–inorganic hybrid perovskite single crystals (OIHP SCs) offer promising opportunity for X-ray detection and imaging owing to their high X-ray attenuation coefficient, excellent optoelectronic properties, and simple fabrication processes. Nevertheless, it remains a key challenge to reduce its dark current and meanwhile maintain a high sensitivity. Herein, we developed an on-substrate method for growing methylamine lead bromide (MAPbBr3) SCs on aluminum oxide (Al2O3) layer coated indium tin oxide (ITO) glass. The photodiode based on this approach exhibits an ultralow-dark-current density of 1 nA cm−2 at an operative voltage of −5 V, a signal-to-noise ratio (SNR) more than 80 dB, and meanwhile retaining a high X-ray sensitivity of 2.02 $\times 10^{{3}}\,\, \mu \text{C}\cdot $ ${\mathrm {Gy}}_{\text {air}}^{-1} \cdot $ cm−2. Our further investigation reveals that the dark current was reduced due to two beneficial effects of the Al2O3 layer in tandem, including the interfacial defect passivation and blocking of hole injection by increased interfacial energy barrier. Our approach sheds light on advancing the fabrication of high-performance OIHP SCs-based X-ray sensors that can be potentially integrated with large-area readout panel at low temperature. [ABSTRACT FROM AUTHOR]

This article presents a wide-spectral response single photon avalanche diode (SPAD) designed and fabricated in advanced 55-nm CMOS image sensor technology. SPADs with different active areas and doping profiles are simulated by Sentaurus-TCAD to optimize their electrical and optical performances. A global well-sharing technique is employed to deliver a pixel pitch of $16.4 ~\mu \text{m}$ and a fill factor of 50.96% for a device with a $6 ~\mu \text{m}$ radius. The proposed structure is based on a p+/deep n-well (DNW) multiplication junction, extending its spectral response as much as possible. Compared to the existing BSI SPADs, a triple protection method is innovatively used to suppress premature edge breakdown and to reduce the dark count rate (DCR) through a combination of a virtual retrograde DNW, p-well guard ring, and a poly gate ring located above the shallow trench isolation. Furthermore, deep trench isolation is employed to suppress crosstalk. Samples of different radii from 2 to $6 ~\mu \text{m}$ are manufactured. The SPADs exhibit a low DCR below 20 cps/ $\mu \text{m}$ 2 at room temperature and with a 2-V excess bias. The peak photon detection probability is 20.3% at 660 nm and is maintained at a high value, more than 10%, in the spectral range of 550–820 nm. [ABSTRACT FROM AUTHOR]

Frenkel pair (FP) formation at HfO2/Ti interface and oxygen vacancy interaction with the filament in HfO2/Ti-based resistive random access memory (ReRAM) are the important mechanisms in the ReRAM operations. In this article, the formation barriers, ${E}_{A}$ , and formation energies of ${V}_{O}/{O}_{i}$ FP across the HfO2/Ti interface with and without preexisting vacancy are calculated using the ab initio tool under zero external electric field. It is found that both the formation barrier and energy can be increased or decreased due to a preexisting oxygen vacancy. The spread of the effect increases inversely with the distance between the FP and the preexisting vacancy. A compact model is then proposed. The parallel migration barrier of an oxygen vacancy at the nearest and the second nearest neighbors (NNs) of a filament is also studied. It is found that the second NN has the lowest barrier due to its ability to retain a +2 charge state. The merging and dissolution of an oxygen vacancy with a filament (equivalent to perpendicular migration) is found to have a similar behavior that +2 states enhance the interaction. It is found that the fourfold coordinated oxygens (4C) and threefold coordinated oxygens (3C) filaments behave similarly during dissolution. However, 4C and 3C filaments prefer merging with 4C and 3C vacancy, respectively. The barrier of merging a +2 4C vacancy with a 4C filament is only 0.56 eV. The data and model obtained from this study may be used to implement device-level simulators, such as kinetic Monte Carlo (KMC) simulators, for ReRAM. [ABSTRACT FROM AUTHOR]

Cross-linking polymer gate dielectric is an efficient strategy to improve its intrinsic properties for high-performance flexible organic field-effect transistors (OFETs). However, the detail optimization process of the polymer films with the various cross-linking degrees is often ignored, which can bring a significant effect on the electrical performance of OFETs. In this work, the cross-linked poly (vinylalcohol) (CPVA) is introduced as the gate dielectrics for the high-performance ultraflexible OFETs. The dielectric property and the surface property of CPVA thin films with various cross-linking degrees are investigated in detail. The OFETs with a high average mobility of 7.3 cm $^{2}\cdot V^{-1}\cdot s^{-1}$ , a current ON/ OFF ratio of over 107, and a lower density of trap states of $8.7\times10$ 11 eV $^{-1}\cdot cm^{-2}$ are achieved successfully. Moreover, the ultraflexible OFET presents a high mobility of over 5.1 cm $^{2}\cdot V^{-1}\cdot s^{-1}$ even bending around a copper wire with a small radius of $400 ~\mu \text{m}$ , due to the ultrathin thickness of the device. These results demonstrate that the CPVA thin film is a promising candidate dielectric material for flexible organic transistors, presenting huge potential for the next-generation flexible electronic devices. [ABSTRACT FROM AUTHOR]