Multipeak Coercive Electric-Field-Based Multilevel Cell Nonvolatile Memory With Antiferroelectric-Ferroelectric Field-Effect Transistors (FETs).

An ultralow program/erase voltage ( |VP/E| = 4 V) is demonstrated by using an antiferroelectric-ferroelectric field-effect transistor (AFE-FE-FET) through a multipeak coercive E -field ( EC ) concept for a four-level stable state with outstanding endurance (>105 cycles) and data retention (>104 s at 65 °C). The mixture of ferroelectric (FE) and AFE domains can provide stable multistate and data storage with zero bias for multilevel cell (MLC) applications. HfZrO2 (HZO) with AFE-FE assembles an orthorhombic/tetragonal (o/t) phase composition and is achieved by [Zr] modulation in an HZO system. MLC characteristics not only improve high-density nonvolatile memory (NVM) but are also beneficial to neuromorphic device applications.

Unipolar Parity of Ferroelectric-Antiferroelectric Characterized by Junction Current in Crystalline Phase Hf1-xZrxO2 Diodes.

Ferroelectric (FE) Hf1-xZrxO2 is a potential candidate for emerging memory in artificial intelligence (AI) and neuromorphic computation due to its non-volatility for data storage with natural bi-stable characteristics. This study experimentally characterizes and demonstrates the FE and antiferroelectric (AFE) material properties, which are modulated from doped Zr incorporated in the HfO2-system, with a diode-junction current for memory operations. Unipolar operations on one of the two hysteretic polarization branch loops of the mixed FE and AFE material give a low program voltage of 3 V with an ON/OFF ratio >100. This also benefits the switching endurance, which reaches >109 cycles. A model based on the polarization switching and tunneling mechanisms is revealed in the (A)FE diode to explain the bipolar and unipolar sweeps. In addition, the proposed FE-AFE diode with Hf1-xZrxO2 has a superior cycling endurance and lower stimulation voltage compared to perovskite FE-diodes due to its scaling capability for resistive FE memory devices.

Visualizing Ferroelectric Uniformity of Hf1-xZrxO2 Films Using X-ray Mapping.

Hf1-xZrxO2 (HZO) is a complementary metal-oxide-semiconductor (CMOS)-compatible ferroelectric (FE) material with considerable potential for negative capacitance field-effect transistors, ferroelectric memory, and capacitors. At present, however, the deployment of HZO in CMOS integrated circuit (IC) technologies has stalled due to issues related to FE uniformity. Spatially mapping the FE distribution is one approach to facilitating the optimization of HZO thin films. This paper presents a novel technique based on synchrotron X-ray nanobeam absorption spectroscopy capable of mapping the three main phases of HZO (i.e., orthorhombic (O), tetragonal (T), and monoclinic (M)). The practical value of the proposed methodology when implemented in conjunction with kinetic-nucleation modeling is demonstrated by our development of a T → O annealing (TOA) process to optimize HZO films. This process produces an HZO film with the largest polarization values (Ps = 64.5 µC cm-2; Pr = 35.17 µC cm-2) so far, which can be attributed to M-phase suppression followed by low-temperature annealing for the induction of a T → O phase transition.

Endoscope rotating technique is useful for difficult colorectal endoscopic submucosal dissection.

BACKGROUND: Conventional lesion-up colorectal ESD has the potential risk of iatrogenic perforation due to the knife's direction toward the muscular layer of the bowel wall. If we rotate the endoscope to the proper position, the mucosal flap is easy to be lifted down by tip attachment and the knife is easy to approach the proper dissection plane, which may prevent the perforation and facilitate difficult ESD. METHODS: We aimed to retrospectively assess the safety and efficacy of this rotating technique compared with the conventional lesion-up dissection regardless of shape, location, or size of the tumor, and investigated in short- and long-term outcomes following the ESD procedure. RESULTS: 41 lesions were enrolled into rotating technique group and 37 lesions in lesion-up group. The dissection speed was significantly faster in the rotating technique group (p = 0.023). R0 resection rate was significantly higher in rotating technique group (p = 0.008). The rate of perioperative complication was significantly higher in lesion-up method group (p = 0.003). Local recurrence was higher in lesion-up group (p = 0.001). Recurrence-free rate was higher in rotating technique group (p = 0.018). CONCLUSION: The endoscope rotating is a useful technique for difficult colorectal ESD due to easy approaching the proper dissection plane. This technique also increases the rate of en bloc resections, R0 resections regardless of size, shape, and location and improves dissection speed without increasing the incidence of adverse events.

Steep Switching of In0.18Al0.82N/AlN/GaN MIS-HEMT (Metal Insulator Semiconductor High Electron Mobility Transistors) on Si for Sensor Applications †.

InAlN/Al/GaN high electron mobility transistors (HEMTs) directly on Si with dynamic threshold voltage for steep subthreshold slope (<60 mV/dec) are demonstrated in this study, and attributed to displacement charge transition effects. The material analysis with High-Resolution X-ray Diffraction (HR-XRD) and the relaxation by reciprocal space mapping (RSM) are performed to confirm indium barrier composition and epitaxy quality. The proposed InAlN barrier HEMTs exhibits high ON/OFF ratio with seven magnitudes and a steep threshold swing (SS) is also obtained with SS = 99 mV/dec for forward sweep and SS = 28 mV/dec for reverse sweep. For GaN-based HEMT directly on Si, this study displays outstanding performance with high ON/OFF ratio and SS < 60 mV/dec behaviors.

Negative-Capacitance Fin Field-Effect Transistor Beyond the 7-nm Node.

In this paper, we investigate the negative-capacitance fin field-effect (NC-FinFET) and extend the design beyond the 7-nm technology node. A 7-nm-node NC-FinFET is presented using the Landau-Khalatnikov equation and the physical equations of a 3D technology computer-aided design simulation. We propose a new NC-FinFET with double ferroelectric hafnium zircon dioxide layers. This device exhibits noticeable voltage gains in the sub-threshold region, can decrease subthreshold swing (SS) effectively, has a wide-ranged uniform SS lower than 60 mV/dec, and can downscale the threshold voltage without increasing the off current. The static noise margin of the static random access memory using the new NC-FinFET is simulated and shows good performance with improved SS and threshold voltage.

Monolithic integration of GaN-based light-emitting diodes and metal-oxide-semiconductor field-effect transistors: reply.

We present some comments to the paper "Monolithic integration of GaN-based light-emitting diodes and metal-oxide-semiconductor field-effect transistors: comment," [Opt. Express22, A1589 (2014)].

Monolithic integration of GaN-based light-emitting diodes and metal-oxide-semiconductor field-effect transistors.

In this study, we report a novel monolithically integrated GaN-based light-emitting diode (LED) with metal-oxide-semiconductor field-effect transistor (MOSFET). Without additionally introducing complicated epitaxial structures for transistors, the MOSFET is directly fabricated on the exposed n-type GaN layer of the LED after dry etching, and serially connected to the LED through standard semiconductor-manufacturing technologies. Such monolithically integrated LED/MOSFET device is able to circumvent undesirable issues that might be faced by other kinds of integration schemes by growing a transistor on an LED or vice versa. For the performances of resulting device, our monolithically integrated LED/MOSFET device exhibits good characteristics in the modulation of gate voltage and good capability of driving injected current, which are essential for the important applications such as smart lighting, interconnection, and optical communication.

The investigation of selective pre-pattern free self-assembled Ge nano-dot formed by excimer laser annealing.

Localized Ge nano-dot formation by laser treatment was investigated and discussed in terms of strain distribution. The advantage of this technique is patterning localization of nano-dots without selective epitaxial growth, reducing costs and improving throughput. Self-assembled Ge nano-dots produced by excimer laser annealing statistically distributed dot density and size dependent on laser energy. Improvement in the crystallization quality of the dots was also studied, and a strain analysis was undertaken.

Combinatorial approach to the development of a single mass YVO(4):Bi(3+),Eu(3+) phosphor with red and green dual colors for high color rendering white light-emitting diodes.

Instead of developing a novel red phosphor individually, this work proposes the production of white light by combining a near-ultraviolet/ultraviolet diode chip with blue and special yellow phosphors: the yellow phosphor includes the red and green components with high color saturation. The availability of this scheme is demonstrated by preparing a white light-emitting diode (WLED) with color rendering index (Ra) up to 90.3. The desired single-mass yellow phosphor is successfully screened out from the YVO(4):Bi(3+),Eu(3+) system by using a combinatorial chemistry approach. When the emission color and luminous efficiency are both considered, the best composition for producing white light is (Y(1-s-t)Bi(s)Eu(t))VO(4) with 0.040 < or = s < or = 0.050 and 0 < t < or = 0.015. The red component that is required for a high-Ra WLED is obtained through sensitizing luminescence of Eu(3+) by Bi(3+) in a YVO(4) host; meanwhile, both Bi(3+) and Eu(3+) emission are improved by keeping the Bi(3+) and Eu(3+) contents close to the critical concentration.