다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

International Technology Roadmap for Semiconductors 2003の要求清浄度について － シリコンウエハ表面と雰囲気環境に要求される清浄度, 分析方法の現状について －

The tunnel field-effect transistor (TFET) is considered a future transistor option due to its steep-slope prospects and the resulting advantages in operating at low supply voltage ( $\mathrm{V}_{\rm DD}$ ). In this paper, using atomistic quantum models that are in agreement with experimental TFET devices, we are reviewing TFETs prospects at $\mathrm{L}_{\rm G}= 13$ nm node together with the main challenges and benefits of its implementation. Significant power savings at iso-performance to CMOS are shown for GaSb/InAs TFET, but only for performance targets which use lower than conventional $\mathrm{V}_{\rm DD}$ . Also, P-TFET current-drive is between $1\times $ to $0.5\times $ of N-TFET, depending on choice of $\mathrm{I}_{\rm OFF}$ and $\mathrm{V}_{\rm DD}$ . There are many challenges to realizing TFETs in products, such as the requirement of high quality III–V materials and oxides with very thin body dimensions, and the TFET’s layout density and reliability issues due to its source/drain asymmetry. Yet, extremely parallelizable products, such as graphics cores, show the prospect of longer battery life at a cost of some chip area.

Tunnel Field-Effect Transistors: Prospects and Challenges

Moore's law technology scaling has improved performance by five orders of magnitude in the last four decades. As advanced technologies continue the pursuit of Moore's law, a variety of challenges will need to be overcome. One of these challenges is the management of process variation. This paper discusses the importance of process variation in modern transistor technology, reviews front-end variation sources, presents device and circuit variation measurement techniques, including circuit and memory data from the 32-nm node, and compares recent intrinsic transistor variation performance from the literature.

Process Technology Variation

Two-dimensional (2D) semiconductors have attracted tremendous interest as atomically thin channels that could facilitate continued transistor scaling. However, despite many proof-of-concept demonstrations, the full potential of 2D transistors has yet to be determined. To this end, the fundamental merits and technological limits of 2D transistors need a critical assessment and objective projection. Here we review the promise and current status of 2D transistors, and emphasize that widely used device parameters (such as carrier mobility and contact resistance) could be frequently misestimated or misinterpreted, and may not be the most reliable performance metrics for benchmarking 2D transistors. We suggest that the saturation or on-state current density, especially in the short-channel limit, could provide a more reliable measure for assessing the potential of diverse 2D semiconductors, and should be applied for cross-checking different studies, especially when milestone performance metrics are claimed. We also summarize the key technical challenges in optimizing the channels, contacts, dielectrics and substrates and outline potential pathways to push the performance limit of 2D transistors. We conclude with an overview of the critical technical targets, the key technological obstacles to the 'lab-to-fab' transition and the potential opportunities arising from the use of these atomically thin semiconductors.

Promises and prospects of two-dimensional transistors

Convolutional neural network (CNN) achieves excellent performance on fascinating tasks such as image recognition and natural language processing at the cost of high power consumption. Stochastic computing (SC) is an attractive paradigm implemented in low power applications which performs arithmetic operations with simple logic and low hardware cost. However, conventional memory structure designed and optimized for binary computing leads to extra data conversion costs, which significantly decreases the energy efficiency. Therefore, a new memory system designed for SC-based multiply-accumulate (MAC) engine applied in CNN which is compatible with conventional memory system is proposed in this paper. As a result, the overall energy consumption of our new computing structure is 0.91pJ, which is reduced by 82.1% compared with the conventional structure, and the energy efficiency achieves 164.8 TOPS/W.

Memory System Designed for Multiply-Accumulate (MAC) Engine Based on Stochastic Computing

Disclosed herein is a method for fabricating an ultra-fine nanowire by combining a trimming process and a mask blocking oxidation process. The ultra-thin nanowire is fabricated by a combination of performing a trimming process on a mask to reduce a width of the mask and blocking an oxidation through the mask. A diameter of the floated ultra-thin nanowire fabricated by the method is controlled to 20 nm below by a thickness of a deposited silicon oxide film, a width of the silicon oxide nanowire after trimming, and a time and a temperature for performing a wet oxidation process. Also, since a speed of the wet oxidation process is faster, the width of the nanowire obtained by a conventional photolithography is reduced faster. Moreover, when fabricating an ultra-thin nanowire by using the method, the cost is reduced and it is more feasible to be implemented.

Method for fabricating ultra-fine nanowire

Disclosed herein is a method for fabricating a FinFET with separated double gates on a bulk silicon, comprising: forming a pattern for a source, a drain and a thin bar connecting the source and the drain; forming an oxidation isolation layer; forming a gate structure and a source/drain structure; and forming a metal contact and a metal interconnection. By means of the method herein, it is very easy to fabricate the FinFET with separated double gates on the bulk silicon wafer, and the overall process flow is completely compatible with the conventional silicon-based very large scale integrated circuit manufacturing technology. Thus, the method herein is simple, convenient and has a short process period, greatly economizing the cost of the silicon wafer. In addition, by employing the FinFET with separated double gates fabricated by the method according to the invention, the short channel effect can be effectively suppressed. Further, the power consumption of the device can be further reduced through the special multi-threshold characteristic of the device with separated double gates.

Method for fabricating FinFET with separated double gates on bulk silicon

In this paper, a comprehensive comparison of analog/RF performance of ultra-thin-body (UTB) GOI and UTB SOI devices is investigated through simulation. Analog/RF figures of merit of GOI and SOI devices are estimated including gm/Id values, intrinsic gain (gm/gd), cutoff frequency (fT), maximum oscillation frequency (fMAX) and intrinsic delay (CV/I). The results show that GOI devices exhibit great gain performance enhancement over SOI devices. Besides, fT and fMAX of GOI devices are also higher than those of SOI devices. Furthermore, GOI devices show strong potential for low-power circuit applications since their advantages over SOI devices are more remarkable biasing at low operating voltages. The results demonstrate that GOI devices exhibit improved analog/RF scaling capability and are suitable for low-voltage, low-power analog/RF circuit applications.

http://iopscience.iop.org/article/10.1088/0268-1242/23/7/075009/pdf

A comparative study on analog/RF performance of UTB GOI and SOI devices

The present invention discloses a method for extracting a trap time constant of a gate dielectric layer in a semiconductor device, which is related to the reliability of microelectronic devices. The method comprises initializing a state of a trap in the semiconductor device so that the trap finally comes to an empty state; applying a DC or AC signal to a gate terminal and a zero bias Vd1 to a drain terminal; after a period of time t1, applying small voltages Vg2 and Vd2 to the gate and drain terminals respectively, and detecting a state of a drain current Id; modifying the time t1 to t2=t1+Δt while maintaining other conditions; repeatedly performing the previous steps in a same manner to perform N times of measurements for N numbers of time points t1, t1+Δt, . . . , t1+(N−1)Δt so as to obtain the respective states of the drain current correspond thereto; conducting moving average and calculating respective occupation probabilities P corresponding to the (N-n) numbers of time points; fitting by using an equation to obtain a trap capture time constant and a trap emission time constant.

Runsheng Wang

Papers

Memory System Designed for Multiply-Accumulate (MAC) Engine Based on Stochastic Computing

Method for fabricating ultra-fine nanowire

Method for fabricating FinFET with separated double gates on bulk silicon

A comparative study on analog/RF performance of UTB GOI and SOI devices

Method for extracting trap time constant of gate dielectric layer in semiconductor device