γ射线辐照对130 nm部分耗尽SOI MOS器件栅氧经时击穿可靠性的影响

研究了射线辐照对130 nm部分耗尽（Partially Depleted,PD）绝缘体上硅（Silicon on Insulator,SOI）工艺MOS器件栅氧经时击穿（Time-Dependent Dielectric Breakdown,TDDB）寿命的影响。通过测试和对比辐照前后NMOS和PMOS器件的转移特性曲线、阈值电压、关态泄漏电流以及TDDB时间等电参数,分析了射线辐照对PD-SOI MOS器件TDDB可靠性的影响。结果表明:由于射线辐照在栅极氧化层中产生了带正电的氧化物陷阱电荷,影响了器件内部势垒的分布,降低了电子跃迁的势垒高度,导致了电子遂穿的正反馈作用增强,从而缩短了器件栅氧化层经时击穿时间,最终造成器件栅极氧化层的可靠性下降。     

一种快速推算栅极氧化膜TDDB寿命的方法

提出了一种快速推算栅极氧化膜TDDB寿命的新方法.该方法可以用于对工艺的实时监控.通常情况下,为了得到栅极氧化膜在器件使用温度下的TDDB寿命,必须得到三个在一定温度下的不同电压下的TDDB寿命.然后使用一定模型(E模型或者1/E模型)和这个三个寿命推算出氧化膜在器件使用温度下的寿命.比较常用的是E模型.但是为了保证使用E模型推得的寿命的准确性,必须尽量使用较低电压下的寿命来推算想要的寿命.显然,为了获得低电压下的TDDB寿命,必须花费相当长的测试时间(甚至1个月).这对于工艺的实时监控来说,是不能接受的.文中提出一种新的推算栅氧化膜TDDB寿命的方法.运用该方法,可以快速、准确获得栅氧化膜的TDDB寿命,而花费的测试时间不到普通方法的1/1000000.在该方法中,巧妙地同时利用了1/E模型和E模型.     

One Method for Fast Gate Oxide TDDB Lifetime Prediction

提出了一种快速推算栅极氧化膜TDDB寿命的新方法.该方法可以用于对工艺的实时监控.通常情况下,为了得到栅极氧化膜在器件使用温度下的TDDB寿命,必须得到三个在一定温度下的不同电压下的TDDB寿命.然后使用一定模型(E模型或者1/E模型)和这个三个寿命推算出氧化膜在器件使用温度下的寿命.比较常用的是E模型.但是为了保证使用E模型推得的寿命的准确性,必须尽量使用较低电压下的寿命来推算想要的寿命.显然,为了获得低电压下的TDDB寿命,必须花费相当长的测试时间(甚至1个月).这对于工艺的实时监控来说,是不能接受的.文中提出一种新的推算栅氧化膜TDDB寿命的方法.运用该方法,可以快速、准确获得栅氧化膜的TDDB寿命,而花费的测试时间不到普通方法的1/1000000.在该方法中,巧妙地同时利用了1/E模型和E模型.     

栅极面积和ESD结构对AlGaN/GaN MIS-HEMTs中LPCVD-SiNx栅介质TDDB特性的影响

基于CMOS兼容性GaN工艺,研制出具有低压化学气相沉积SiNx栅介质的硅基AlGaN/GaN异质结金属-绝缘层-半导体高电子迁移率晶体管(MIS-HEMTs)器件。通过威布尔统计分析,研究了栅介质面积和静电释放(ESD)结构对SiNx的经时击穿(TDDB)特性的影响。结果表明,较小的栅介质面积有利于更长的器件寿命,而ESD保护结构有利于提升器件栅介质在高电压应力下的可靠性和稳定性,主要原因为SBD的寄生电容可有效吸收电脉冲感应在介质薄膜中产生的电荷。最后,通过线性E模型预测具有35 nm厚LPCVD-SiNx栅介质的AlGaN/GaN MIS-HEMTs在栅极电压为13 V条件下的击穿寿命可达20年(0.01%,T=25℃)。     

高温恒定电场栅氧化层TDDB寿命测试方法研究

介绍了薄栅氧化层TDDB可靠性评价的高温恒定电场试验方法,并完成了E模型的参数提取,同时以MOS电容栅电流Ig为失效判据。对某工艺的MOS电容栅氧化层TDDB寿命进行了评价。该试验方法解决了在高温条件下对工作器件进行可靠性评价的问题,方法简便可靠,适用于亚微米和深亚微米工艺线的可靠性评价。     

薄棚氧化层的TDDB研究

随着超大规模集成电路的不断发展,薄栅氧化层的质量对器件和电路可靠性的作用越来越重要.经时绝缘击穿(TDDB)是评价薄栅氧化层质量的重要方法.本文重点介绍了TDDB的几种主要击穿模型和机理,比较了软击穿和硬击穿过程的联系与区别,并初步分析了TDDB与测试电场、温度以及氧化层厚度的关系.     

薄栅氧化层的TDDB研究

随着超大规模集成电路的不断发展,薄栅氧化层的质量对器件和电路可靠性的作用越来越重要。经时绝缘击穿(TDDB)是评价薄栅氧化层质量的重要方法。本文重点介绍了TDDB的几种主要击穿模型和机理,比较了软击穿和硬击穿过程的联系与区别,并初步分析了TDDB与测试电场、温度以及氧化层厚度的关系。     

栅氧化层TDDB可靠性评价试验及模型参数提取

采用恒定电压和恒定电流试验方法对20nm栅氧化层进行了TDDB可靠性评价试验，并完成了1／E模型参数提取，给出了恒定电流应力下描述氧化层TDDB退化的统计模型，较好地解释了试验结果。     

SOI抗总剂量辐射加固工艺栅氧可靠性研究

文章对采用了埋层二氧化硅抗总剂量加固工艺技术的SOI器件栅氧可靠性进行研究,比较了干法氧化和湿法氧化工艺的栅氧击穿电荷,干法氧化的栅氧质量劣于湿法氧化。采用更敏感的12.5nm干法氧化栅氧工艺条件,对比采用抗总剂量辐射加固工艺前后的栅氧可靠性。抗总剂量辐射加固工艺降低了栅氧的击穿电压和击穿时间。最后通过恒压法表征加固工艺的栅氧介质随时间击穿(TDDB)的可靠性,结果显示抗总剂量辐射加固工艺的12.5nm栅氧在常温5.5V工作电压下TDDB寿命远大于10年,满足SOI抗总剂量辐射加固工艺对栅氧可靠性的需求。     

抗辐射SOI器件栅氧可靠性研究

对抗辐射SOI器件栅氧可靠性进行研究,比较了体硅器件、SOI器件、抗总剂量加固SOI器件的栅氧可靠性,发现SOI材料片的制备与抗总剂量加固过程中的离子注入工艺都会对顶层硅膜造成影响,进而影响栅氧可靠性。最后通过恒压应力法表征栅氧介质随时间击穿(TDDB)的可靠性,结果显示抗总剂量辐射加固工艺的12.5 nm栅氧在125℃高温5.5 V工作电压下TDDB寿命达到14.65年,满足SOI抗总剂量辐射加固工艺对栅氧可靠性的需求。     

Hybrid Aging Delay Model Considering the PBTI and TDDB

With a 45 nm process technique, the shrinking silicon feature size brings in a high-k/metal gate which significantly exacerbates the positive bias temperature instability (PBTI) and time-dependent dielectric breakdown (TDDB) effects of a NMOS transistor. However, previous works presented delay models to characterize the PBTI or TDDB individually. This paper demonstrates that the delay caused by the joint effects of PBTI and TDDB widely differs from the cumulated result of the delay caused by the PBTI and TDDB, respectively, with the experiments on an inverter chain. This paper proposes a hybrid aging delay model comprising both the PBTI and TDDB effects by analyzing the relationship between the aging propagation delay and the inherent delay of the gate. Experimental results on the logic gates under 45 nm, 32 nm, 22 nm, and 16 nm CMOS technologies show that the maximum error between the proposed model and the actual value is less than 2.5%, meanwhile the average error is about 1.5%.     

Oxide reliability of drain engineered I/O NMOS from hot carrier injection

The impact of hot carrier stress on the breakdown properties of I/O NMOS gate oxide is reported. I/O NMOS devices with drain structures using standard LDD with pocket (S-LDD) and graded LDD without pocket (G-LDD) are used. Time-dependent (TDDB) and voltage-ramp (VRDB) dielectric breakdown tests are performed for devices with and without hot-carrier-injection. It is demonstrated that both I/O structures show similar oxide integrity after hot carrier injection (HCI) when the Idsat degradation is small (<5%), but show significantly different oxide lifetimes when the Idsat degradation is high (>5%). At 10% I/sub dsat/ degradation, the oxide lifetime for the G-LDD structure is reduced by about a factor of 10 compared to that of the S-LDD structure. The correlation between oxide integrity and leakage current indicates that the oxide charge introduced by HCI stress is the reason for oxide degradation. This work clearly demonstrates that the effect of hot carrier induced oxide damage must be included when predicting the oxide lifetimes of advanced I/O NMOS devices.     

Investigation into the correct statistical distribution for oxide breakdown over oxide thickness range

A critical aspect of integrated circuit manufacturing is the reliability of the components, in particular the gate oxide of transistors and capacitors. There are two statistical distributions, which can be applied to accelerated stress test failure data, namely the Lognormal or the Weibull distributions. The failure data can fit each distribution equally well. However both distributions will give vastly different lifetime predictions and their correct use is crucial for accurate lifetime prediction. A statistical based test, developed with Monte Carlo data, which is designed to decide if a failure data set has an underlying Lognormal or Weibull distribution is applied to empirical Time Dependent Dielectric Breakdown (TDDB) failure tests. The TDDB tests are carried out on 7 nm, 15 nm and 20 nm thick gate oxides. The results generated show the importance of making the correct choice between the two distributions for accurate lifetime prediction and validate the test for different oxide thickness. Also investigated are the effects of choosing the incorrect statistical distribution has on the voltage and temperature acceleration factors.     

Time dependent breakdown of ultrathin gate oxide

Time dependent dielectric breakdown (TDDB) of ultrathin gate oxide (<40 Å) was measured for a wide range of oxide fields (3.4<|E_ox|<10.3 MV/cm) at various temperatures (100⩽T⩽342°C). It was found that TDDB of ultrathin oxide follows the E model. It was also found that TDDB t₅₀ starts deviating from the 1/E model for fields below 7.2 MV/cm. Below 4.8 MV/cm, TDDB t₅₀ of intrinsic oxide increased above the value predicted by the E model obtained for fields >4.8 MV/cm. The TDDB activation energy for this type of gate oxide was found to have linear dependence on oxide field. In addition, we found that γ (the field acceleration parameter) decreases with increasing temperature. Furthermore, it was found that testing at high temperatures (up to 342°C) and low electric field values did not introduce new gate oxide failure mechanism. It is also shown that TDDB data obtained at very high temperature (342°C) and low fields can be used to generate TDDB model at lower temperatures and low fields. Our results (an enthalpy of activation of 1.98 eV and dipole moment of 12.3 eÅ) are in complete agreement with previous results by McPherson and Mogul. Additionally, it was found that TDDB is exponentially dependent on the gate voltage     

薄栅氧化层斜坡电压TDDB寿命评价

随着超大规模集成电路的不断发展，薄栅氧化层的质量对器件和电路可靠性的作用越来越重要。经时绝缘击穿（TDDB）是评价薄栅氧化层质量的重要方法。文章着重于薄栅氧化层TD-DB可靠性评价的斜坡电压试验方法的研究，基于斜坡电压实验，提取模型参数，分别利用线性场模型和定量物理模型，外推出工作电压下栅氧化层的寿命。通过分析斜坡电压实验时氧化层的击穿过程，提出斜坡电压实验时利用统一模型外推栅氧化层的寿命比较合适。     

Total dose responses and reliability issues of 65 nm NMOSFETs

In this paper, total dose responses and reliability issues of MOSFETs fabricated by 65 nm CMOS technology were examined. "Radiation-induced narrow channel effect" is observed in a narrow channel device. Similar to total dose responses of NMOSFETs, narrow channel NMOSFEs have larger hot-carrier-induced degradation than wide channel devices. Step Time-Dependent Dielectric Breakdown (TDDB) stresses are applied, and narrow channel devices have higher breakdown voltage than wide channel devices, which agree with "weakest link" theory of TDDB. Experimental results show that linear current, transconductance, saturated drain current and subthreshold swing are superposed degenerated by total dose irradiation and reliability issues, which may result in different lifetime from that considering total dose irradiation reliability issues separately.