Bottom oxide Bulk FinFETs Without Punch-Through-Stopper for Extending Toward 5-nm Node

Structural advancements of 5-nm node bulk fin-shaped field-effect transistors (FinFETs) without punch-through-stopper (PTS) were introduced using fully calibrated TCAD for the first time. It is challenging to scale down conventional bulk FinFETs into 5-nm technology node due to the sub-fin leakage increase. Meanwhile, bottom oxide deposition after anisotropic etching for source/drain (S/D) epi formation prevents the sub-fin leakage effectively even without the PTS doping, thus achieving better gate-to-channel controllability. Bottom oxide FinFETs also have smaller gate capacitances than do conventional FinFETs because the parasitic capacitances decrease by smaller S/D epi separated from the bottom Si layer, which reduces junction and outer-fringing capacitances. But smaller S/D epi decreases the stresses along the channel direction, and the effective widths decrease by the bottom oxide layer blocking the current paths at the bottom side of fin channels. Furthermore, increase of the interconnect resistance and capacitance parasitics down to 5-nm node diminishes the improvements of total delays as the interconnect wire length increases greatly. In spite of these drawbacks, 5-nm node bottom oxide FinFETs achieve smaller total delays than do the 7-nm node conventional FinFETs, especially for low-power applications, thus promising for the scalability of bulk FinFETs along with simple and reliable process by avoiding PTS step.11Ysciescopu

Whole-brain imaging with receive-only multichannel top-hat dipole antenna RF coil at 7 T MRI

This work investigates the construction and performance of an eight-channel top-hat dipole receiver RF coil with a capacitive plate to increase the longitudinal whole-brain coverage and receiver sensitivity gain in the brain at 7 T MRI. The construction method for top-hat dipole-based receiver RF coil by adjusting the length and structure corresponding to each channel consists of tuning, matching, balun, and detuning circuitry. Electromagnetic simulations were analyzed on a 3-D human model to evaluate B1+ efficiency and specific absorption rate deposition. Coil performance was evaluated in the human head imaging in vivo. EM simulation results indicated a higher B1− sensitivity in the brain and z-directional coverage of the proposed eight-channel receiver RF coil. The MR images were acquired with an identical field of view showing the receiver coverage improvement in the brain when capacitive plates are used. The MR images also show the clear visibility of the complete set of the cervical vertebrae as well as the spinal cord. The acquired MRI results demonstrate the capability of the proposed RF coil to increase the receiver coverage in the longitudinal direction. Moreover, the B1+ efficiency, as well as receiver sensitivity in the brain, can be substantially improved with the use of multilayered capacitive plates of proper shape and size in conjunction with an RF coil

Source/Drain Patterning FinFETs as Solution for Physical Area Scaling Toward 5-nm Node

A novel and feasible process scheme to downsize the source/drain (S/D) epitaxy of 5-nm node bulk fin-shaped field-effect transistors (FinFETs) were introduced by using fully-calibrated TCAD for the first time. The S/D epitaxy formed by selective epitaxial growth was diamond-shaped and occupied a large proportion of the device size irrespective of the active channel area. However, this problem was solved by patterning the low-k regions prior to S/D formation by preventing the lateral overgrowth of S/D epitaxy; the so-called S/D patterning (SDP). Its smaller S/D epitaxy decreased the average longitudinal channel stresses and drive currents for NFETs. However, the small diffusions of the boron dopants into the channel regions improved the short-channel effects and alleviated the drive current reduction for PFETs. Gate capacitances decreased greatly by reducing outer-fringing capacitances between the metal-gate stack and S/D regions. Through SPICE simulation based on the virtual source model, operation frequencies and dynamic powers of 15-stage ring oscillators were studied. SDP FinFETs have better circuit performances than the conventional and bottom oxide bulk FinFETs along with smaller active areas, promising for further area scaling through simple and reliable S/D process.11Ysciescopu

Gate-All-Around FETs: Nanowire and Nanosheet Structure

DC/AC performances of 3-nm-node gate-all-around (GAA) FETs having different widths and the number of channels (Nch) from 1 to 5 were investigated thoroughly using fully-calibrated TCAD. There are two types of GAAFETs: nanowire (NW) FETs having the same width (WNW) and thickness of the channels, and nanosheet (NS) FETs having wide width (WNS) but the fixed thickness of the channels as 5 nm. Compared to FinFETs, GAAFETs can maintain good short channel characteristics as the WNW is smaller than 9 nm but irrespective of the WNS. DC performances of the GAAFETs improve as the Nch increases but at decreasing rate because of the parasitic resistances at the source/drain epi. On the other hand, gate capacitances of the GAAFETs increase constantly as the Nch increases. Therefore, the GAAFETs have minimum RC delay at the Nch near 3. For low power applications, NWFETs outperform FinFETs and NSFETs due to their excellent short channel characteristics by 2-D structural confinement. For standard and high performance applications, NSFETs outperform FinFETs and NWFETs by showing superior DC performances arising from larger effective widths per footprint. Overall, GAAFETs are great candidates to substitute FinFETs in the 3-nm technology node for all the applications

Effects of 92% oxygen administration on cognitive performance and physiological changes of intellectually and developmentally disabled people

Background: The present study addressed how 92% oxygen administration affects cognitive performance, blood oxygen saturation (SpO(2)), and heart rate (HR) of intellectually and developmentally disabled people. Methods: Seven males (28.9 +/- 1.8 years) and seven females (34.4 +/- 8.3 years) with intellectual and developmental disabilities (disabled level 2.1 +/- 0.5) completed an experiment consisting a 0-back task with normal air (21% oxygen) administered in one run and hyperoxic air (92% oxygen) administered in the other run. The experimental sequence in each run consisted of a 1-min adaptation phase, 2-min control phase, and 2-min 0-back task phase, where SpO(2) and HR were gauged for each phase. Results: The administration of 92% oxygen increased 0-back task performance of intellectually and developmentally disabled people, in association with increased SpO(2) and decreased HR. Our results demonstrate that sufficient oxygen supply subserving cognitive functions, even as a short-term effect, could increase cognitive ability for the intellectually and developmentally disabled people. Conclusions: It is concluded that enriched oxygen can positively affect, at least in the short-term, the working memory of those with intellectual and developmental disabilityopen0

Time Pattern Locking Scheme for Secure Multimedia Contents in Human-Centric Device

Among the various smart multimedia devices, multimedia smartphones have become the most widespread due to their convenient portability and real-time information sharing, as well as various other built-in features. Accordingly, since personal and business activities can be carried out using multimedia smartphones without restrictions based on time and location, people have more leisure time and convenience than ever. However, problems such as loss, theft, and information leakage because of convenient portability have also increased proportionally. As a result, most multimedia smartphones are equipped with various built-in locking features. Pattern lock, personal identification numbers, and passwords are the most used locking features on current smartphones, but these are vulnerable to shoulder surfing and smudge attacks, allowing malicious users to bypass the security feature easily. In particular, the smudge attack technique is a convenient way to unlock multimedia smartphones after they have been stolen. In this paper, we propose the secure locking screen using time pattern (SLSTP) focusing on improved security and convenience for users to support human-centric multimedia device completely. The SLSTP can provide a simple interface to users and reduce the risk factors pertaining to security leakage to malicious third parties