Experimental confirmation of an accurate CMOS gate delay model forgate oxide and voltage scaling

MOSFET's and CMOS ring oscillators with gate oxide thicknesses from 2.58 nm to 5.7 nm and effective channel lengths down to 0.21 μm have been studied at voltages from 1.5 V to 3.3 V. Physical and electrical measurement of gate oxide thicknesses are compared. Ring oscillators' load capacitance is characterized through dynamic current measurement. An accurate model of CMOS gate delay is compared with measurement data. It shows that the dependence of gate propagation delay on gate oxide, channel length, and voltage scaling can be predicted     

新结构MOSFET

和传统平面结构MOSFET相比，新结构MOSFET具有更好的性能(如改善的沟道效应(SCE)，理想的漏诱生势垒降低效应(DIBL)和亚阈值特性)和更大的驱动电流等。文章主要介绍了五种典型的新结构MOSFET，包括平面双栅MOSFET、FinFET、三栅MOSFET、环形栅MOSFET和竖直结构MOSFET。随着MOSFET向亚50nm等比例缩小，这些新结构器件将大有前途。     

Study of Scaling Trends in Energy Recovery Logic: An Analytical Approach

This paper presents an analytical model to study the scaling trends in energy recovery logic. The energy performance of conventional CMOS and energy recovery logic are compared with scaling the design and technology parameters such as supply voltage, device threshold voltage and gate oxide thickness. The proposed analytical model is validated with simulation results at 90 nm and 65 nm CMOS technology nodes and predicts the scaling behavior accurately that help us to design an energy-efficient CMOS digital circuit design at the nanoscale. This research work shows the adiabatic switching as an ultra-low-power circuit technique for sub-100 nm digital CMOS circuit applications.     

Metallized ultra-shallow-junction device technology for sub-0.1μm gate MOSFET's

This paper describes a new ultra-thin SOI-CMOS structure offering reduced parasitic diffusion-layer resistance. It addresses ways to deal with the ultra-shallow junctions required by sub-0.1 μm MOSFET's. Based on a CVD tungsten process we experimentally investigate the characteristics of selectively grown tungsten used in the source and drain region made in SOI layers of various thicknesses ranging from 10 to 100 nm. We also investigate certain CMOS device characteristics. The SOI-CMOS structure, with low parasitic diffusion-layer resistance and good contact characteristics for ultra-shallow junction devices exhibits superior device performance and high scalability     

超深亚微米自对准平面双栅MOSFET假栅的制作

进入超深亚微米领域以后,传统CMOS器件遇到了器件物理、工艺技术等方面难以逾越的障碍.普遍认为,必须引入新结构和新材料来延长摩尔定律的寿命.其中,双栅CMOS被认为是新结构中的首选.在制作平面型双栅MOS器件中,采用自对准假栅结构,利用UHV外延得到有源区(S、D、G),是一种制作自对准双栅MOSFET的有效手段.文章详细研究了一种假栅制作技术.采用电子束曝光,结合胶的灰化技术,得到了线宽为50 nm的胶图形,并用RIE刻蚀五层介质的方法,得到了栅长仅为50 nm的自对准假栅结构.     

Electron and hole mobility enhancement in strained-Si MOSFET's onSiGe-on-insulator substrates fabricated by SIMOX technology

We have newly developed strained-Si MOSFET's on a SiGe-on-insulator (strained-SOI) structure fabricated by separation-by-implanted-oxygen (SIMOX) technology. Their electron and hole mobility characteristics have been experimentally studied and compared to those of control SOI MOSFET's. Using an epitaxial regrowth technique of a strained-Si film on a relaxed-Si_0.9Ge_0.1 layer and the conventional SIMOX process, strained-Si (20 nm thickness) layer on fully relaxed-SiGe (340 nm thickness)-on-buried oxide (100 nm thickness) was formed, and n-and p-channel strained-Si MOSFET's were successfully fabricated. For the first time, the good FET characteristics were obtained in both n-and p-strained-SOI devices. It was found that both electron and hole mobilities in strained-SOI MOSFET's were enhanced, compared to those of control SOI MOSFET's and the universal mobility in Si inversion layer     

Low-Power SRAMs in Nanoscale CMOS Technologies

As CMOS technology scaling is advancing beyond 100 nm, it has become increasingly difficult to meet the power and performance goals for various product applications while achieving aggressive area scaling in static random access memory (SRAM) development. This paper addresses many of the most pressing challenges in today's SRAM design from perspectives of both process technology optimization and design innovation. Key process tradeoff and optimization along with the advanced circuit design techniques for power management and low-voltage operation are discussed.     

具有应变沟道及EOT 1.2nm高性能栅长22nm CMOS器件

深入研究了亚30nm CMOS关键工艺技术，特别是提出了一种新的低成本的提高空穴迁移率的技术--Ge预非晶化S/D延伸区诱生沟道应变技术，它使栅长90nm pMOS空穴有效迁移率在0.6MV/cm电场下提高32%. 而且空穴有效迁移率的改善，随器件特征尺寸缩小而增强. 利用零阶劳厄线衍射的大角度会聚束电子衍射分析表明，在沟道区相应的压应变为-3.6%. 在集成技术优化的基础上，研制成功了高性能栅长22nm应变沟道CMOS器件及栅长27nm CMOS 32分频器电路（其中分别嵌入了57级/201级环形振荡器）, EOT为1.2nm,具有Ni自对准硅化物.     

VLSI scaling methods and low power CMOS buffer circuit

Device scaling is an important part of the very large scale integration(VLSI) design to boost up the success path of VLSI industry, which results in denser and faster integration of the devices. As technology node moves towards the very deep submicron region, leakage current and circuit reliability become the key issues. Both are increasing with the new technology generation and affecting the performance of the overall logic circuit. The VLSI designers must keep the balance in power dissipation and the circuit’s performance with scaling of the devices. In this paper, different scaling methods are studied first. These scaling methods are used to identify the effects of those scaling methods on the power dissipation and propagation delay of the CMOS buffer circuit. For mitigating the power dissipation in scaled devices, we have proposed a reliable leakage reduction low power transmission gate(LPTG) approach and tested it on complementary metal oxide semiconductor(CMOS) buffer circuit. All simulation results are taken on HSPICE tool with Berkeley predictive technology model(BPTM) BSIM4 bulk CMOS files. The LPTG CMOS buffer reduces 95.16% power dissipation with 84.20% improvement in figure of merit at 32 nm technology node. Various process, voltage and temperature variations are analyzed for proving the robustness of the proposed approach. Leakage current uncertainty decreases from 0.91 to 0.43 in the CMOS buffer circuit that causes large circuit reliability.     

Analysis of leakage currents and impact on off-state powerconsumption for CMOS technology in the 100-nm regime

Off-state leakage currents have been investigated for sub-100 nm CMOS technology. The two leakage mechanisms investigated in this work include conventional off-state leakage due to short channel effects and gate leakage through ultrathin gate oxides. The conventional off-state leakage due to short channel effects exhibited the similar characteristics as previously published; however, gate leakage introduces two significant consequences with respect to off-state power consumption: (1) an increase in the number of transistors contributing to the total off-state power consumption of the chip and (2) an increase in the conventional off-state current due to gate leakage near the drain region of the device. Using experimentally measured data, it is estimated that gate leakage does not exceed the off-state specifications of the National Technology Roadmap for Semiconductors for gate oxides as thin as 1.4 to 1.5 nm for high performance CMOS. Low power and memory applications may be limited to an oxide thickness of 1.8 to 2.0 nm in order to minimize the off-state power consumption and maintain an acceptable level of charge retention. The analysis in this work suggests that reliability will probably limit silicon oxide scaling for high performance applications whereas gate leakage will limit gate oxide scaling for low power and memory applications     

高温CMOS数字集成电路直流传输特性的分析

分析了高温CMOS倒相器和门电路的直流传输特性,建立了相应的解析模型。根据分析,高温MOSFET阈值电压和载流子迁移率的降低,以及MOSFET漏端pn结泄漏电流的增加引起了CMOS倒相器和门电路直流传输特性劣化。在MOSFET漏端pn结泄漏电流的影响下,高温CMOS倒相器和门电路的输出高电平下降,低电平上升,导致了电路的功能失效。给出的理论模型和实验结果一致。     

Transient drain current and propagation delay in SOI CMOS

The transient overshoot in drain current that occurs in thin-film SOI (Si-on-SiO2) MOSFET's because of the floating body in analyzed, and the benefit it can provide to propagation delay (speed) in SOI CMOS digital circuits is assessed. The analysis accounts for the charge coupling between the front and back gates, and hence describes the dependence of the transient drain (saturation) current and propagation delay on the back-gate bias as well as on the switching frequency. Measurements of the transient current in recrystallized SOI MOSFET's and of propagation delay in SOI CMOS inverters and ring oscillators are described and shown to support the theoretical analysis. The current overshoot is especially beneficial in low-voltage circuits, although at high frequencies other floating-body effects can degrade the speed.     

深亚微米MOSFET热载流子退化机理及建模的研究进展

本文给出了深亚微米ＭＯＳ器件热载流子效应及可靠性研究与进展,对当前深亚微米ＭＯＳ器件中的主要热载流子现象以及由其引起的器件性能退化的物理机制进行了详细论述。不仅对热电子,同时也对热空穴的影响进行了重点研究,为深亚微米ＣＭＯＳ电路热载流子可靠性研究奠定了基础。本文还讨论了深亚微米器件热载流子可靠性模型,尤其是ＭＯＳ器件的热载流子退化模型。     

A comprehensive study of hot-carrier instability in p- and n-typepoly-Si gated MOSFET's

A comprehensive comparison of hot-carrier instability between p- and n-type poly Si-gated MOSFET's is presented in this paper. The electron trapping and interface state generation in the 7 nm gate oxide of MOSFET's are investigated using uniform hot-electron injection from a buried junction injector (BJI) and channel-hot-carrier stress. From BJI experiments, electron trapping (instead of oxide trap generation) and interface state generation are shown to be the major effects of hot-electron injection. Electron trapping and interface state generation are found to be similar in both p- and n-type poly-Si gated MOSFET's. The dependences of interface state generation by hot electrons on oxide voltages and temperatures are observed to be similar between n- and p-type poly-Si gated MOSFET's. From the results of channel-hot-carrier stress on surface-channel n- and p-channel MOSFET's, it was also found that the channel-hot-carrier instabilities of p- and n-type poly-Si gated MOSFET's are comparable     

Scaling-parameter-dependent model for subthreshold swing S indouble-gate SOI MOSFET's

We derived a simple formula for the subthreshold swing S in double-gate (DG) SOI MOSFET's. Our formula, which depends only on a scaling device parameter, matches the device simulation results. From these results, our equations are simple and give a scaling rule for DG-SOI MOSFET's     

Silicon-gate n-well CMOS process by full ion-implantation technology

A silicon-gate n-well CMOS process for an application of digital circuits operated by TTL compatible supply voltage was developed. Full ion-implantation technology, a new photolithography technique, n⁺-doped polysilicon gate which contain no boron impurities, and thin gate oxide of 65 nm can realize CMOS circuits of 2-µm gate length. Average impurity concentrations measured from substrate bias effect of MOSFET's and junction depth are in good agreement with those expected from impurity profiles calculated by a simple diffusion theory. So, the process design for CMOS circuits operated by any supply voltage is possible, by adjusting threshold voltages. The process can easily be extended to n-MOS/CMOS process (E/D MOS and CMOS on the same chip), if a photomask to fabricate depletion-type n-MOSFET's is provided.     

Single Event crosstalk shielding for CMOS logic

With advances in technology scaling, CMOS circuits are increasingly more sensitive to transient pulses caused by Single Event particles. Hardening techniques for CMOS combinational logic have been developed to address the problems associated with Single Event transients, but in these designs, Single Event crosstalk effects have been ignored. In order to complement the Single Event upset (SEU) hardening process, coupling effects among interconnects need to be considered in the Single Event hardening and analysis of CMOS logic gates due to technology scaling effects that increase both SE vulnerability and crosstalk effects. As technologies advance, the coupling effects increasingly cause SE transients to contaminate electronically unrelated circuit paths which can in turn increase the “Single Event susceptibility” of CMOS circuits. Serious effects may occur if the affected line is a clock line or an input line of voters in triple-modular redundancy (TMR) circuit. Hence, this work first analyzes Single Event crosstalk on recent technologies and then proposes hardening techniques to reduce Single Event crosstalk. Hardening results are demonstrated using HSpice Simulations with interconnect and device parameters derived in 90 nm technology.     

全耗尽SOI MOSFET及CMOS／SOI电路的研究

采用ＳＩＭＯＸ材料，研制了一种全耗尽ＣＭＯＳ／ＳＯＩ模拟开关电路，研究了全耗尽ＳＯＩ ＭＯＳ场效应晶体管的阈值电压与背栅偏置的依赖关系，对漏源击穿的Ｓｎａｐｂａｃｋ特性进行分析，介绍了薄层ＣＭＯＳ／ＳＩＭＯＸ制作工艺，给出了全耗尽ＣＭＯＳ／ＳＯＩ电路的测试结果。     

Halo结构器件研究综述

随着集成电路产业的迅速发展,CMOS工艺已进入≥22nm特征尺寸的研究。讨论了Halo结构在当前工艺尺寸等比例缩小挑战背景下的应用情况。与传统长沟器件结构进行了比较,指出由于短沟效应(SCE)和漏致势垒降低(DIBL)效应需要专门工艺来克服,Halo注入通过在沟道两侧形成高掺杂浓度区,达到对SCE和DIBL进行有效抑制的目的,现已成为备受关注的结构。针对有关Halo的研究内容进行综述,并对其在CMOS工艺等比例缩小进程中所起的作用进行评述,对Halo的发展趋势进行了展望。     

An Efficient 5‐Input Exclusive‐OR Circuit Based on Carbon Nanotube FETs

The integration of digital circuits has a tight relation with the scaling down of silicon technology. The continuous scaling down of the feature size of CMOS devices enters the nanoscale, which results in such destructive effects as short channel effects. Consequently, efforts to replace silicon technology with efficient substitutes have been made. The carbon nanotube field‐effect transistor (CNTFET) is one of the most promising replacements for this purpose because of its essential characteristics. Various digital CNTFET‐based circuits, such as standard logic cells, have been designed and the results demonstrate improvements in the delay and energy consumption of these circuits. In this paper, a new CNTFET‐based 5‐input XOR gate based on a novel design method is proposed and simulated using the HSPICE tool based on the compact SPICE model for the CNTFET at the 32‐nm technology node. The proposed method leads to improvements in performance and device count compared to the conventional CMOS‐style design.