快速评价半导体器件失效激活能的方法

通过对序进应力加速寿命试验的研究,提出了一种快速评价半导体器件失效激活能的方法,建立了计算失效激活能的理论模型.并对硅pnp三极管3CG120进行额定功率下,170～345℃范围内的序进应力加速寿命试验,快速提取器件失效敏感参数hFE与所施加应力的关系,根据模型对器件退化过程中的失效机理进行研究、计算,从而确定其对应的失效激活能.     

S波段硅微波功率晶体管的加速寿命试验

为了在尽量短的时间内对S波段硅微波功率晶体管的长期可靠性进行研究,依据温度应力阿列尼乌斯(Arrhenius)模型,进行了两种S波段硅微波功率晶体管的可靠性寿命评价试验。试验采用步进应力加速寿命试验摸底,找出了最高试验应力水平,并根据摸底结果分别进行了3组恒定应力加速寿命试验,最高试验壳温分别为250℃和220℃,大幅度提高了温度应力,加快了试验速度。试验全程采用数据采集卡实施实时监测,并对失效样品进行了失效分析,最大程度地保证了试验数据的准确性。通过对试验结果的统计分析,推算出了两种S波段硅微波功率晶体管的平均寿命。     

大功率LED加速寿命试验及问题分析

采用国家标准(GB1772)规定的电子元器件加速寿命试验方法,选择了工作环境温度作为加速应力,设计了四个应力等级的大功率LED加速寿命试验方案并进行试验.试验结果为每个应力等级下的失效模式有2～3种,不同应力级别确定的激活能有一定的差异.通过对金丝引线球焊处开裂、金属化层失效等主要失效机理的产生原因以及温度、电流密度之间关系分析,认为基于Arrhenius模型进行大功率LED加速寿命试验存在不足和缺陷,不能准确地预测稳态温度下的LED寿命,应当对Arrhenius模型进行修正.     

微波晶体管可靠性预测

本报告给出了73.2～74.4所做的关于估价微波功率晶体管失效机理的结果,并给出了这些器件预期的可靠性和寿命结果。根据详细的失效分析进行了一系列加速射频寿命试验。估价了金和铝两种金属化系统器件。早期的工作是在 MSC1315和 PHI1510器件上进行的。PHI 型金金属化器件可在340℃结温下工作长达2000小时而不失效。MSC 型铝金属化器件在250℃结温下工作800小时或在310℃结温下工作10小时失效。其主要失效机理是电徙动。     

步进应力加速寿命试验的分析

本文以“产品的残余寿命仅依赖于当时已累积失效的部分和当时的应力条件,而不考虑如何去累积这部分”的假设为基础,采用时间折合的方法分析了Arrhenius模型的步进应力加速试验结果。这种分析方法把步进应力试验中得到的累积失效分布看成是由恒定应力条件下累积失效分布的各段组成。利用CG35晶体管在150℃、175℃、185℃、200℃、210℃条件下的步进温度贮存加速试验结果的简易分析为例做了说明。并用150℃、175℃、210℃,恒定温度贮存加速试验结果做了验证。步进应力试验结果与恒定应力试验结果二者有好的一致。     

基于Arrhenius模型快速评价功率VDMOS可靠性

基于Arrhenius模型,对功率器件垂直导电双扩散(VDMOS)场效应晶体管的可靠性进行了评价,并对其主要失效机理进行了分析.通过样管在不同结温下的恒定温度应力加速寿命实验,利用Arrhenius方程和最好线性无偏差估计法(BLUE)对结果进行数据处理,得到其失效激活能E=0.54 eV,在偏置VDs=7.5 V,IDs=0.8 A,推导出功率VDMOS在室温下工作的寿命特征值为3.67×106 h.失效分析发现,栅极累积失效是影响功率VDMOS漏源电流,IDs退化的主要失效机理.     

加速试验中失效机理一致性的判别方法

通过对电子器件加速试验失效模型--Arrhenius模型的研究,发现加速试验过程中,失效机理不发生改变时,电子器件失效敏感参数的退化速率与施加应力的负倒数遵从指数关系,从而提出了一种加速试验失效机理一致性的判定方法.对样品3DG130进行了150～310℃的序进应力加速试验,快速得到了失效机理一致的应力范围,验证了该方法的可行性.     

加速试验中失效机理一致性的判别方法

通过对电子器件加速试验失效模型--Arrhenius模型的研究,发现加速试验过程中,失效机理不发生改变时,电子器件失效敏感参数的退化速率与施加应力的负倒数遵从指数关系,从而提出了一种加速试验失效机理一致性的判定方法.对样品3DG130进行了150～310℃的序进应力加速试验,快速得到了失效机理一致的应力范围,验证了该方法的可行性.     

晶体管的热稳定性及其失效机理研究

在晶体管可靠性研究中,一般采用各种应力等级的加速寿命试验预计其失效速率。同时,人们也很注重现场应用中器件的失效分析。本文主要是讨论晶体管的热稳定性及其与非热稳定性有关的失效机理,在这里不详细说明可靠性试验方法。     

CG36晶体管恒定应力加速寿命试验

本文总结了CG36晶体管加电功率的恒定应力加速寿命试验结果。阐述了开展加速寿命试验的必要性,半导体器件加速寿命试验的基本原理,本试验的目的和试验方案的考虑。通过试验证实了器件的寿命分布服从对数正态分布,外推了器件在使用状态下的寿命和失效率水平;提出了对于加电功率的加速试验不应简单地运用经典的阿列尼乌斯方程,对某些器件尤其是微波器件必须考虑电压和电流的因子对失效的影响,对加速方程进行必要的修正。本试验共投入了1000只样品,其结果可作为整机可靠性设计的依据。     

基于加速环境的可靠性指标验证试验

首先进行了电子产品失效模型的理论研究,并利用加速退化试验技术而研究了某通信产品失效机理一致的应力范围,通过对试验数据进行的统计分析,计算出失效机理一致情况下的激活能。在可靠性指标验证的试验研究中,将试验样品分成若干组分别进行恒温加速验证试验,并将试验结果与现场统计数据进行比较,最终确定产品的MTBF。     

Effects of different test profiles of temperature cycling tests on the reliability of RFID tags

Passive UHF radio-frequency identification (RFID) tags are used for object identification in various environmental conditions, which may affect the reliability of these tags. The effects of different environmental stresses can be studied with accelerated life tests (ALT). Choosing the most suitable test may be challenging: The results are needed as fast as possible, but the failure mechanisms must replicate those occurring in the real operating environment. Here the effects of different temperature cycling profiles were studied by altering temperature ranges, extreme temperatures, soak times to extreme temperatures and transition times between extreme temperatures. Failure times clearly differed between the tests. The test with the fastest transition time and the shortest soak time seemed to have the most acceleration. It was also observed that the different temperature cycling profiles affected the failure mechanisms detected. Cracking of the antenna was observed with lower temperature extremes or shorter soak and transition times. However, with longer soak and transition times, cracks were seen in the RFID interconnections. Both cases led to changes in the impedance matching and consequently to failures. The totally different failure mechanisms clearly demonstrate the importance of carefully determining the test parameters in order to achieve the correct failure mechanism.     

High current bond design rules based on bond pad degradation and fusing of the wire

In this paper design rules for maximum current handling capability of gold bond wires are derived based on two failure mechanisms: (1) fusing of the wire; and (2) degradation of the interface between gold bond balls and the aluminum bond pads under high current/high temperature stress. For determination of the fuse current as a function of the length an analytical model is used to calculate the temperature and power distribution in the wire as a function of the position. The current level at which the melt temperature of gold is reached is the fuse current. The degradation mechanism under high current stress (up to 2.5 A) was studied by in-situ monitoring of the gold bond ball–aluminum interconnect contact resistance under high current stress at various temperatures and stress currents. The cumulative failure distributions were used to fit a model for lifetime as a function of current and temperature that shows an order of magnitude difference in lifetime between positive and negative current stress. Finally, fuse current and the lifetime model result in data-driven high current design rules for bond pad and wire.     

Features of conduction mechanisms in Si/oligo-β-naphthol/metal heterostructures

Conduction mechanisms in Si-polymer-metal heterostructures with oligo-β-naphthol as a wide band-gap polymer have been studied. The results obtained are explained within the models of hopping transport via trap levels, Schottky emission, and field tunneling emission. Different charge transport mechanisms operate in different temperature ranges and under different electric fields.     

电子产品可靠性评价与物理模型应用探讨

该文以电子产品的故障为出发点,从集成电路-封装、集成电路-芯片、电路板(或线路板)、电子元件、系统和多系统的角度论述了不同任务环境下电子器件的故障机理特点。系统论述了故障模式、影响及危害性分析(FMECA)和故障模式、机理与影响分析(FMMEA)两种故障机理分析方法,同时结合低周疲劳、高周疲劳、裂纹萌生、反应论模型、芯片失效等失效机理对故障物理元模型进行分类讨论,对电子产品可靠性评价与物理模型应用进行了系统的探讨,为电子产品可靠性评价及失效物理评估模型的选取提供了依据。     

Outstanding Low-Temperature Performance of Structure-Controlled Graphene Anode Based on Surface-Controlled Charge Storage Mechanism

The energy and power performance of lithium (Li)-ion batteries is significantly reduced at low-temperature conditions, which is mainly due to the slow diffusion of Li-ions in graphite anode. Here, it is demonstrated that the effective utilization of the surface-controlled charge storage mechanism through the transition from layered graphite to 3D crumpled graphene (CG) dramatically improves the Li-ion charge storage kinetics and structural stability at low-temperature conditions. The structure-controlled CG anode prepared via a one-step aerosol drying process shows a remarkable rate-capability by delivering ≈206 mAh g^–1 at a high current density of 10 A g^–1 at room temperature. At an extremely low temperature of −40 °C, CG anode still exhibits a high capacity of ≈154 mAh g^–1 at 0.01 A g^–1 with excellent rate-capability and cycling stability. A combination of electrochemical studies and density functional theory (DFT) reveals that the superior performance of CG anode stems from the dominant surface-controlled charge storage mechanism at various defect sites. This study establishes the effective utilization of the surface-controlled charge storage mechanism through structure-controlled graphene as a promising strategy to improve the charge storage kinetics and stability under low-temperature conditions.     

Reliability life-testing and failure-analysis of GaAs monolithicKu-band driver amplifiers

`Gallium-arsenide monolithic microwave integrated-circuit (MMIC) Ku-band driver amplifiers were life tested under accelerated high temperature, DC and RF conditions until failure. These MMIC are used in various applications such as radar and satellite communication systems. The failure mechanisms controlling their reliability must be understood in order to improve the lifetime for these and other applications. This paper discusses the experimental procedures, statistical evaluation of the data and failure analysis of the devices. To the authors' knowledge, this is the first report of RF life testing of dual-gate driver amplifiers. The majority of the devices failed catastrophically due to high drain current, while others failed parametrically due to low output power. Failure analysis indicates that degradation of the Si₃N₄ dielectric layer to be the main failure mechanism in these MMIC. Statistical analysis revealed an activation energy of 0.87 eV and a median lifetime of 5.8·10⁴ hours at 140°C channel temperature, which is consistent with surface-phenomena failure mechanisms     

Power cycling test and failure analysis of molded Intelligent Power IGBT Module under different temperature swing durations

Molded IGBT modules are widely used in low power motor drive applications due to their advantage like compactness, low cost, and high reliability. Thermo-mechanical stress is generally the main cause of degradation of IGBT modules and thus much research has been performed to investigate the effect of temperature stresses on IGBT modules such as temperature swing and steady-state temperature. The temperature swing duration is also an important factor from a real application point of view, but there is a still lack of quantitative study. In this paper, the impact of temperature swing duration on the lifetime of 600 V, 30 A, 3-phase molded Intelligent Power Modules (IPM) and their failure mechanisms are investigated. The study is based on the accelerated power cycling test results of 36 samples under 6 different conditions and tests are performed under realistic electrical conditions by an advanced power cycling test setup. The results show that the temperature swing duration has a significant effect on the lifetime of IGBT modules. Longer temperature swing duration leads to the smaller number of cycles to failure. Further, it also shows that the bond-wire crack is the main failure mechanism of the tested IGBT modules.     

Low-Cycle Fatigue Behavior of 95.8Sn-3.5Ag-0.7Cu Solder Joints

Low-cycle fatigue (LCF) behavior of 95.8Sn-3.5Ag-0.7Cu solder joints was investigated over a range of test temperatures (25°C, 75°C, and 125°C), frequencies (0.001 Hz, 0.01 Hz, and 0.1 Hz), and strain ranges (0.78%, 1.6%, and 3.1%). Effects of temperature and frequency on the LCF life were studied. Results show that the LCF lifetime decreases with an increase in test temperature or a decrease of test frequency, which is attributed to the longer exposure time to creep and the stress relaxation mechanism during fatigue testing. A modified Coffin–Manson model considering effects of temperature and frequency on the LCF life is proposed. The fatigue exponent and ductility coefficient were found to be influenced by both the temperature and frequency. By fitting the experimental data, the mathematical relations between the fatigue exponent and temperature, and ductility coefficient and temperature, were analyzed. Scanning electron microscopy (SEM) of the cross-sections and fracture surfaces of failed specimens at different temperature and frequency was applied to verify the failure mechanisms.     

Investigation of Arrhenius acceleration factor for integrated circuit early life failure region with several failure mechanisms

Use of the Arrhenius equation for analysis of burn-in and life test data has been called into question in recent years. Validity of the Arrhenius activation energy is asserted to be restricted to only one failure mechanism. Therefore, if multiple failure mechanisms apply to an integrated circuit type, the temperature acceleration factor must be complex. In this study a model is constructed using the Weibull distribution for the failure rate applicable when there are multiple failure mechanisms. In this model a different Arrhenius activation energy corresponds to each failure mechanism. It is shown that under conditions expected to be valid for most integrated circuits, an empirical effective Arrhenius activation energy can be computed that is valid for life test data taken under typical conditions to better than 10%. This provides some justification for the continued usage of a simple Arrhenius equation as an empirical model to analyze life test data.