SOI器件中瞬态浮体效应的模拟与分析

针对SOI器件中的瞬态浮体效应进行了一系列的数值模拟,通过改变器件参数,比较系统地考察了SOI器件中瞬态浮体效应,同时也研究和分析了瞬态浮体效应对CMOS/SOI电路(以环振电路为例)的影响,并提出了抑制器件浮体效应的器件结构和参数优化设计.     

0.5μm部分耗尽SOI MOSFET中的寄生双极效应

0.5μm部分耗尽SOI MOSFET的寄生双极效应严重影响了SOI器件和电路的抗单粒子和抗瞬态γ辐射能力。文中显示,影响0.5μm部分耗尽SOI NMOSFET寄生的双极器件特性的因素很多,包括NMOSFET的栅上电压、漏端电压和体接触等,尤其以体接触最为关键。在器件处于浮体状态时,0.5μm SOI NMOSFET的寄生双极器件很容易被触发,导致单管闭锁。因此,在设计抗辐射SOI电路时,需要尽量降低SOI NMOSFET寄生双极效应,以提高电路的抗单粒子和抗瞬态γ辐射能力。     

部分耗尽型SOI CMOS模拟电路设计研究

介绍了部分耗尽型SOI MOS器件浮体状态下的Kink效应及对模拟电路的影响.阐述了4种常用体接触方式及其他消除部分耗尽型SOI MOS器件Kink效应的工艺方法,同时给出了部分耗尽型SOIMOSFET工作在浮体状态下时模拟电路的设计方法.     

PD SOI MOSFET低频噪声研究进展

随着器件尺寸的不断减小,PD SOI器件的低频噪声特性对电路稳定性的影响越来越大.研究了PD SOI器件低频过冲噪声现象,分析了此类器件在发生浮体效应、栅致浮体效应以及前背栅耦合效应时低频过冲噪声的产生机理及影响因素.最后指出,可以通过添加体接触或将PD SOI器件改进为双栅结构,达到有效抑制低频过冲噪声的目的.     

体串联电阻对体接触SOI数字D触发器速度特性的影响

在用体接触结构设计的SOI电路中,浮体效应被压制了,但是体串联电阻的存在仍旧在远离体接触的体区产生局部浮体效应。对于数字电路来说,浮体效应会影响他们的速度。本文采用体接触结构设计了数字D触发器,并制造了这种电路,展示了电路的性能。实际器件的输出特性表明了浮体效应的存在。SPICE模拟表明体串联电阻对体接触SOI数字D触发器速度特性有明显的影响。     

0.5μm SOI CMOS器件和电路

研究了0.5μm SOI CMOS器件和电路,开发出成套的0.5μm SOI CMOS工艺.经过工艺投片,获得了性能良好的器件和电路,其中当工作电压为3V时,0.5μm 101级环振单级延迟为42ps.同时,对部分耗尽SOI器件特性,如“浮体”效应、“kink”效应和反常亚阈值特性进行了讨论.     

0.5μm SOI CMOS器件和电路

研究了 0 .5μm SOI CMOS器件和电路 ,开发出成套的 0 .5μm SOI CMOS工艺 .经过工艺投片 ,获得了性能良好的器件和电路 ,其中当工作电压为 3V时 ,0 .5μm 10 1级环振单级延迟为 42 ps.同时 ,对部分耗尽 SOI器件特性 ,如“浮体”效应、“kink”效应和反常亚阈值特性进行了讨论     

SOI技术问题和BSIM3SOIv1.3模型参数特点

SOI器件具有高速、低压、低功耗、抗辐照、耐高温等体硅器件不具备的优点,SOI CMOS技术开始用于深亚微米高速、低功耗、低电压大规模集成电路应用。但SOI技术还面临浮体效应、自加热效应等问题的挑战。作为SOI模型国际标准,BSIM3SOIv1.3提出了新的模型参数解决方案。BSIMPDSPICE器件模型是基于物理意义的模型,是在体硅MOS器件模型工业标准(BSIM3V3)的基础上开发而成,BSIMPD针对SOI固有的浮体效应引起的动态特性,自加热和体接触提出相应的模型参数。     

一种采用局域注氧技术制备的新型DSOI器件

为了克服传统SOI器件的浮体效应和自热效应,采用创新的工艺方法将低剂量局域SIMOX工艺及传统的CMOS工艺结合,实现了DSOI结构的器件.测试结果表明,该器件消除了传统SOI器件的浮体效应,同时自热效应得到很大的改善,提高了可靠性和稳定性.而原先SOI器件具备的优点得到了保留.     

一种采用局域注氧技术制备的新型DSOI器件

为了克服传统SOI器件的浮体效应和自热效应,采用创新的工艺方法将低剂量局域SIMOX工艺及传统的CMOS工艺结合,实现了DSOI结构的器件.测试结果表明,该器件消除了传统SOI器件的浮体效应,同时自热效应得到很大的改善,提高了可靠性和稳定性.而原先SOI器件具备的优点得到了保留     

Grasping SOI floating-body effects

It is important to understand what the floating-body effects are and how they affect device and circuit behavior. In this regard, this article qualitatively explains the device physics underlying DC and transient floating-body effects, clearly implying their influence on circuits, and thereby giving good insight into PD/SOI CMOS design issues. The article also notes special but practical device and circuit designs for controlling floating-body effects, showing through simulation how PD/SOI offers a significant performance advantage over bulk silicon in low-voltage applications, thereby conveying an assurance that reliable SOI CMOS design is feasible     

Effect of floating-body charge on SOI MOSFET design

This work presents a new method for assessing the effect of floating-body charge on a fully- and partially-depleted Silicon-on-Insulator (SOI) MOSFET device design space. Floating-body effects under transient conditions are incorporated into the device design parameters threshold voltage V_T and off-current I_0FF using calibrated two-dimensional (2-D) device simulation. Simulation methodology which reveals the worst-case bounds of the device design parameters, from idle to switching-steady-state, is presented and applied to a CMOS inverter example. Using this methodology, the worst-case shifts in V_T and I_0FF due to hysteretic floating-body charge are quantified for devices in L _eff=0.2- and 0.1-μm design spaces. Methods to reduce floating-body effects are discussed including a demonstration of how reducing the effective bulk carrier lifetime widens the 0.1-μm design space     

A physical charge-based model for non-fully depleted SOI MOSFET'sand its use in assessing floating-body effects in SOI CMOS circuits

A new model for the non-fully depleted (NFD) SOI MOSFET is developed and used to study floating-body effects in SOI CMOS circuits. The charge-based model is physical, yet compact and thus suitable for device/circuit simulation. Verified by numerical device simulations and test-device measurements, and implemented in (SOI)SPICE, it reliably predicts floating-body effects resulting from free-carrier charging in the NFD/SOI MOSFET, including the purportedly beneficial supra-ideal sub-threshold slope due to impact ionization and a saturation current enhancement due to thermal generation. SOISPICE CMOS circuit simulations reveal that the former effect is not beneficial and could be detrimental, but the latter effect can be beneficial, especially in low-voltage applications, when accompanied by a dynamic floating-body effect that effectively reduces static power. The dynamic floating-body effects are hysteretic, however, and hence exploitation of the beneficial ones will necessitate device/circuit design scrutiny aided by physical models such as the one presented herein     

Physical modeling of temperature dependences of SOI CMOS devicesand circuits including self-heating

To simulate and examine temperature and self-heating effects in Silicon-On-Insulator (SOI) devices and circuits, a physical temperature-dependence model is implemented into the SOISPICE fully depleted (FD) and nonfully depleted (NFD) SOI MOSFET models. Due to the physical nature of the device models, the temperature-dependence modeling, which enables a device self-heating option as well, is straightforward and requires no new parameters. The modeling is verified by DC and transient measurements of scaled test devices, and in the process physical insight on floating-body effects in temperature is attained. The utility of the modeling is exemplified with a study of the temperature and self-heating effects in an SOI CMOS NAND ring oscillator. SOISPICE transient simulations of the circuit, with floating and tied bodies, reveal how speed and power depend on ambient temperature, and they predict no significant dynamic self-heating, irrespective of the ambient temperature     

Analysis of floating body induced transient behaviors in partiallydepleted thin film SOI devices

Emphasis toward manufacturability of thin film SOI devices has prompted more attention on partially depleted devices. In this paper, drain current transients in partially depleted SOI devices due to floating-body effects are investigated quantitatively. A one-dimensional analytical model is developed to predict the transient effect and MEDICI simulation is performed to confirm the model. With the model, the amount of the turn-on current enhancement and the turn-off current suppression are calculated. The transient characteristics can be used in investigating the quality of the SOI materials by determining the carrier lifetime. The impact of the transient effect on the device parameter extraction is described     

Monitoring hot-electron-induced degradation of floating-body SOIMOSFETs

A simple model relating the hot-electron-controlled device lifetime of floating-body SOI MOSFETs to the body voltage is discussed. The model is derived from the familiar relationship between the device lifetime and the substrate current of bulk MOSFETs, a relationship that cannot be measured directly in floating-body MOSFETs. The model, which allows quick estimation of the device lifetime from body-voltage measurements, is supported by measurements of hot-electron-induced degradation of floating-body SOI MOSFETs fabricated using SIMOX substrates     

Low-voltage transient bipolar effect induced by dynamicfloating-body charging in scaled PD/SOI MOSFETs

An increased significance of the parasitic bipolar transistor (BJT) in scaled floating-body partially depleted SOI MOSFETs under transient conditions is described. The transient parasitic BJT effect is analyzed using both simulations and high-speed pulse measurements of pass transistors in a sub-0.25 μm SOI technology. The transient BJT current can be significant even at low drain-source voltages, well below the device breakdown voltage, and does not scale with technology. Our analysis shows that it can be problematic in digital circuit operation, possibly causing write disturbs in SRAMs and decreased retention times for DRAMs. Proper device/circuit design, suggested by our analysis, can however control the problems     

Effects of floating body on double polysilicon partially depleted SOI nonvolatile memory cell

The floating-body effect of nonvolatile memory cells fabricated using partially depleted silicon-on-insulator (SOI) technology has been investigated using two-dimensional numerical device simulation. Compared with similar bulk devices, the floating-body effect of partially depleted SOI MOSFETs introduces instability in the value of the drain current during sensing and extra hot-electron gate current in programming. The effects of the drain-current instability on the error margins in read operation are studied. The floating-body effect is found to be heavily dependent on biasing condition.     

Minimizing floating-body-induced threshold voltage variation inpartially depleted SOI CMOS

Pulse propagation problems associated with dynamic floating-body effects, e.g., pulse stretching, is measured in partially depleted SOI CMOS inverter chains. Pulse stretching is found to be dependent on pulse frequency and V_DD. Such behavior is attributed to floating-body-induced transient threshold voltage variation in partially depleted SOI CMOS devices due to floating-body charge imbalance between logic states during CMOS switching. Such an imbalance can be minimized through proper device design because of the different dependencies of the gate and drain depletion charges on channel length, silicon film thickness, gate oxide thickness, channel doping, and supply voltage. This is confirmed by measuring the maximum transient threshold voltage variation in discrete partially depleted SOI NMOS devices in configurations which are predictive of CMOS switching behavior     

Temperature dependence of hot-carrier-induced degradation in 0.1μm SOI nMOSFETs with thin oxide

This letter investigates hot-carrier-induced degradation on 0.1 μm partially depleted silicon-on-insulator (SOI) nMOSFETs at various ambient temperatures. The thermal impact on device degradation was investigated with respect to body-contact nMOSFETs (BC-SOI) and floating-body SOI nMOSFETs (FB-SOI). Experimental results show that hot-carrier-induced degradation on drive capacity of FB-SOI devices exhibits inverse temperature dependence compared to that of BC-SOI devices. This is attributed to the floating-body effect (FBE) and parasitic bipolar transistor (PBT) effect