塑封半导体器件的可靠性增长分析

应用ＥＤＲＩＣ可靠性模型对彩电配套用塑封整流二极管进行了增长分析,讨论了该器件的失效模式、失效机理及增长对策,使该器件的可靠性得到了较大的增长。     

Noise as a diagnostic and prediction tool in reliability physics

A review of the possibility of using noise measurements in analysis and prediction of electron device reliability is given. The noise as an informative parameter for device reliability and its advantages and disadvantages are discussed. A review of qualitative and quantitative noise reliability indicators for diodes, transistors and integrated circuits as well as the methods for failure and defect analysis are presented.     

The reliability of laser diodes and laser transmitter modules

This paper reviews the reliability of laser transmitter modules for use in optical fibre transmission systems. Methods for reliability testing and lifetime prediction are discussed and the dominant failure mechanisms affecting laser modules are described. The current status of laser module reliability is discussed, based on both published results, and on the findings of a study at BT Laboratories of the reliability of commercial laser modules from ten manufacturers. It is concluded that significant progress has been made in the reliability of laser diodes, through the understanding of basic failure mechanisms, leading to long predicted lifetimes for a number of different laser structures. However, module packaging is less reliable and further work is required to identify and eliminate those materials and processing technologies which lead to the risk of early failure.     

Reliability investigation and characterization of failure modes in Schottky diodes

Schottky diodes may be realized by various techniques, depending on application and processing technology. M/A-COM has recently developed an enhancement/depletion (E/D) pHEMT process, used primarily for control circuits around its mature RF circuitry. We report here a reliability study of two diodes (configured using E-FETs), subjected to both high temperature and forward bias accelerated stress. Different failure modes observed during accelerated life tests of the two diode configurations are discussed, and the causes for aging are analyzed. Results of the stress test are backed by equivalent circuit modeling using ADS™. The differences in the effect of these failure modes on circuit performance are discussed.     

Thermally accelerated life testing of single mode, double-heterostructure, AlGaAs laser diodes operated pulsed at 50mW peak power

Single spatial mode, double-heterostructure, channel-substrate-planar AlGaAs laser diodes have been life tested under thermally accelerated conditions to characterize the reliability of the diodes in a digital, optical communication system intended for space application. The diodes were operated pulsed under constant drive current conditions at 50 mW peak power, 25 ns pulse width, and 1 percent duty cycle in a dry, inert environment at ambient test temperatures at 40,55, and 70°C. Diode performance parameters as related to the space application, such as pulsewidth, peak power, wavelength spectrum, spatial mode, and threshold current, were periodically monitored. Tests have continued for over 14 000 h. The test results for all diodes with failure defined by power degradation alone is compared to the test results for single mode diodes with failure defined by power degradation, wavelength shift and spatial mode changes. It is found that the life test results are substantially equivalent but differ from earlier published reports for laser diodes operated CW. An activation energy of about 0.39 eV is deduced with a predicted median life of about5 times 10^{4}h at 20 °C. These values are somewhat lower than those found for diodes operated CW and are attributed to the use of single mode laser diodes here. It is concluded that thermally accelerated life testing for single spatial mode laser diodes must incorporate a means to separate bulk material, current, and optical density induced degradation effects. A test scheme is proposed.     

Highly Reliable High-Power 86-GHz Components and Transmitter--Receiver Modules

The reliability of semiconductor active devices is related to the junction temperature of diodes used. This paper describes the reliability design and performance of 86-GHz active components and transmitter-receiver modules for a guided millimeter-wave transmission system. The components are IMPATT oscillators, IMPATT amplifiers, varactor frequency multipliers, and Schottky-barrier diode upconverters. The maximum output powers of these active devices are calculated for a given mean time between failure (MTBF). Active components and transmitter-receiver modules for 86-GHz operation were manufactured based upon the design with considerations for reliability as well as RF performance.     

Estimation of system reliability for uncooled optical transmittersusing system reliability function

This paper investigates the system reliability for 155 Mb/s optical transmitters by deriving a system reliability function from reliability data of each component for transmitters, laser diode, photodiode, optical assembly, and driver IC. The reliability data for each component reliability function have been obtained from accelerated aging test. The reliability parameters such as failure rate, mean time-to-failure (MTTF), standard deviation are obtained from a probability plotting method. From the system reliability function, the MTTF of the optical transmitter at 65°C was estimated to be 47000 h with 95% confidence. In this estimation, we introduced modified lifetime of laser diodes and reliability function of optical assembly     

Roughness-enhanced reliability of MOS tunneling diodes

Both electrical and optical reliabilities of PMOS and NMOS tunneling diodes are enhanced by oxide roughness, prepared by very high vacuum prebake technology. For rough PMOS devices, as compared to flat PMOS devices, the Weibull plot of T_BD shows a 2.5-fold enhancement at 63% failure rate, while both the D₂ and H₂-treated flat PMOS devices show similar inferior reliability. For rough NMOS devices, as compared to flat NMOS devices, the Weibull plot of T_BD shows a 4.9-fold enhancement at 63% failure rate. The time evolutions of the light emission from rough PMOS and NMOS diodes degrade much less than those of flat PMOS and NMOS diodes. The momentum reduction perpendicular to the Si/SiO₂ interface by roughness scattering could possibly make it difficult to form defects in the bulk oxide and at the Si/SiO₂ interface by the impact of the energetic electrons and holes     

Micro-Raman spectroscopy applied in crystal structure analysis on the ESD failure mechanism of SiC JBS diodes

This paper propose a novel reliability analysis approach for electrostatic discharge (ESD) stress on 4H-SiC junction barrier Schottky (JBS) diodes using the technology of Micro-Raman spectroscopy. Several conventional analysis are firstly used to determine the failure site after the JBS diodes are destructed by ESD stress, including optical microscope (OM), Photoemission microscopy (PEM) and scanning electron microscopy (SEM). Then, the Micro-Raman spectroscopy is applied to analyze element identification and crystal structure of micro failure site. The analysis reveals that high electric field and high temperature concentrate in the high-voltage termination, resulting in diode burnout and changing the physical microstructure of base SiC. Furthermore, in the micro failure site, 4H-SiC with different Raman spectrum from base 4H-SiC are clearly found, and carbon escapes out from base SiC by combustion, leaving a mixture of amorphous silicon and polysilicon, which is decomposed from the base SiC on the failure surface.     

Reliability problems in TTL-LS devices

An analysis of the possible failure modes of TTL-LS was carried out, with particular emphasis on long term thermal stability of Schottky diodes, all realized by PtSi - Ti/W - Al metallization system.Only from one supplier were there diodes in which changes in the characteristics, due to metallization defects, were observed during accelerated thermal cycles. On the contrary, once its uniformity is guaranteed, the Ti/W barrier layer inhibits the Si-Al interdiffusion up to 550 °C, 1 hr thermal annealing.Sensitivity to negative input pulses and electrical overstresses were also investigated.Scanning electron microscope and microprobe, and voltage contrast techniques seem to be more suitable instruments to investigate the reliability of such devices than the conventional life tests.The technology employed today seems provide suitable reliability for TTL Low-Power Schottky devices.     

Light emitting diodes reliability review

The increasing demand for light emitting diodes (LEDs) has been driven by a number of application categories, including display backlighting, communications, medical services, signage, and general illumination. The construction of LEDs is somewhat similar to microelectronics, but there are functional requirements, materials, and interfaces in LEDs that make their failure modes and mechanisms unique. This paper presents a comprehensive review for industry and academic research on LED failure mechanisms and reliability to help LED developers and end-product manufacturers focus resources in an effective manner. The focus is on the reliability of LEDs at the die and package levels. The reliability information provided by the LED manufacturers is not at a mature enough stage to be useful to most consumers and end-product manufacturers. This paper provides the groundwork for an understanding of the reliability issues of LEDs across the supply chain. We provide an introduction to LEDs and present the key industries that use LEDs and LED applications. The construction details and fabrication steps of LEDs as they relate to failure mechanisms and reliability are discussed next. We then categorize LED failures into thirteen different groups related to semiconductor, interconnect, and package reliability issues. We then identify the relationships between failure causes and their associated mechanisms, issues in thermal standardization, and critical areas of investigation and development in LED technology and reliability.     

WT55型1.25厘米体效应管加速寿命试验

本文给出了WT55型1.25厘米体效应管加直流工作点,以环境温度为加速变量的寿命试验结果.器件的突然烧毁严重影响其可靠性,使失效率约为10~(-5)/小时.然而,试验表明,器件实际寿命可达数百万小时.高温直流功率负荷筛选能有效地淘汰早期失效器件,尤其是淘汰突然烧毁失效器件.选择适当的筛选条件,将使器件在40℃环境温度下工作时,获得低于1000菲特的失效率.文章讨论了筛选条件的选择.严格封帽前的镜检,对提高器件可靠性有积极意义.     

Comparison of power cycling reliability of flexible PCB interconnect smaller/thinner and larger/thicker power devices with topside Sn-3.5Ag solder joints

The power cycling reliability of flexible printed circuit board (PCB) interconnect smaller/thinner (ST) 9.5 mm × 5.5 mm × 0.07 mm and larger/thicker (LT) 13.5 mm × 13.5 mm × 0.5 mm single Si diode samples have been studied. With the assumption of creep strain accumulation-induced fatigue cracking as the failure mechanism of the Sn-3.5Ag solder joints, finite element (FE) simulations predicted a higher power cycling reliability of soldering the flexible PCB on a ST Si diode than on a LT Si diode under similar power cycling conditions. Then the power cycling test results of 10 samples for each type are reported and discussed. The samples were constructed with commercially available ST Si diodes with 3.2/0.5/0.3 μm thick AlSiCu/NiP/Pd topside metallization and LT Si diodes with 5/0.1/1/1 μm thick Al/Ti/Ni/Ag topside metallization. In contradiction with the FE prediction, most ST Si diode samples were less reliable than those LT Si diode samples. This can be attributed to the fact that the failure of the ST diode samples was associated with the weak bonding and hence the shear-induced local delamination of the topside solder joints from the AlSiCu metallization, while the failure of the LT diode samples was mainly caused by the creep strain accumulation-induced fatigue cracking within the solder joints. Such results can be used to not only provide better understanding of the different failure mechanisms, but also demonstrate the importance of employing an appropriate topside metallization on the power devices.     

Reliability of semiconductor lasers for undersea optical transmission systems

The reliability of laser diodes developed for undersea optical transmission systems is analyzed. Up to 1000 device samples of two types (DC-PBH and VSB) are used. An aging test with constant light power operation of 5 mW is carried out at 10, 50, and 70°C for 10 000 h. The median lifetime at 10°C is conservatively estimated to be 1.6 × 10⁶hours. Failure rate at 10°C is estimated at 250 FIT's at 25 years of service for the wear-out failure mode and at less than 50 FIT's for the random failure mode with a sufficient margin. Furthermore, it is determined that reliability can be further improved by selection of long-life lasers through an additional third step screening aging.     

Reliability of photovoltaic systems using seasonal mission profiles and the FIDES methodology

In areas with hot weather, photovoltaic systems can be used to help relieve the peak demand caused by air conditioning equipment. Users, however, are reluctant to invest in solar technology, arguing that the equipment commercially available is unreliable because it was developed for others environments. In this paper, the reliability assessment of a DC/DC converter aimed at PV applications is presented. The reliability estimation was performed following the FIDES methodology, taking into account seasonal mission profiles developed for five specific sites for which there is meteorological data available. The goal was to identify the most failure prone components, and the dominant stress factors. It was found that the smallest contribution to the failure rate occurs during winter. The largest contribution occurs in spring or summer, depending on the site. In the converter, the most failure-prone components were the diodes, which contributed with about 70% of the overall failure rate.     

Analysis of rapid degradation in high-power (AlGa)As laser diodes

A multitemperature accelerated life test conducted to determine the lifetime and reliability of semiconductor lasers for long-term space applications is discussed. The primary cause of failure during two of these life tests (heat sink temperatures of -20°C and 50°C, respectively) was identified as carbon contamination on the front facet resulting in an initially rapid but saturable decrease in output power. The carbon contamination on the facet was the sole cause of the decrease in power for most of the laser diodes from the -20°C test. Removing the sources of carbon from the laser diodes eliminated the front facet degradation, and this resulted in increased laser diode lifetime in subsequent life tests. The index of refraction and the absorption coefficient of the contamination found on the laser diodes from the -20°C test were calculated. the resulting values compared favorably with those reported by other researchers for amorphous hydrogenated carbon     

Reliability of semiconductor lasers for undersea optical transmission systems

The reliability of laser diodes developed for undersea optical transmission systems is analyzed. Up to 1000 device samples of two types (DC-PBH and VSB) are used. An aging test with constant light power operation of 5 mW is carried out at 10, 50, and 70°C for 10 000 h. The median lifetime at 10°C is conservatively estimated to be1.6 times 10^{6}hours. Failure rate at 10°C is estimated at 250 FIT's at 25 years of service for the wear-out failure mode and at less than 50 FIT's for the random failure mode with a sufficient margin. Furthermore, it is determined that reliability can be further improved by selection of long-life lasers through an additional third step screening aging.     

A Review on the Physical Mechanisms That Limit the Reliability of GaN-Based LEDs

We review the failure modes and mechanisms of gallium nitride (GaN)-based light-emitting diodes (LEDs). A number of reliability tests are presented, and specific degradation mechanisms of state-of-the-art LED structures are analyzed. In particular, we report recent results concerning the following issues: 1) the degradation of the active layer induced by direct current stress due to the increase in nonradiative recombination; 2) the degradation of LEDs submitted to reverse-bias stress tests; 3) the catastrophic failure of advanced LED structures related to electrostatic discharge events; 4) the degradation of the ohmic contacts of GaN-based LEDs; and 5) the degradation of the optical properties of the package/phosphors system of white LEDs. The presented results provide important information on the weaknesses of LED technology and on the design of procedures for reliability evaluation. Results are compared with literature data throughout the text.     

Thermal reliability and performances of InGaP schottky contact with Cu/Au and Au/Cu-MSM photodetectors

We report the Schottky performance and thermal reliability of a wide bandgap InGaP layer in contact with a Cu/Au metallic system. An effective Schottky barrier height of 0.97 eV and an ideality factor of 1.21 can be achieved. The thermal reliability of the resultant Schottky barrier diodes was analyzed using Auger electron spectroscopy and atomic force microscopy. The thermal reliability could be main tained up to 450°C. The failure mechanism was attributable to the decomposition of the InGaP layer and the interdiffusion of the chemical elements at higher temperature. Insensitive photoresponsivity with the in cident optical power was found for the resultant Au/Cu-metal-semiconductor-metalphotodetectors (MSM-PDs). According to the measured temporal response of the Au/Cu-MSM-PDs, the operation frequency could be above 10 GHz.     

对GaAs衬底表面进行氩离子清洗的研究

介绍了离子清洗技术在提高980nm半导体激光器可靠性方面的应用。外延片在空气中解理后，半导体激光器的腔面会吸附上碳和氧等杂质。腔面吸附的氧和碳严重影响了器件的可靠性。本文用GaAs衬底表面模拟半导体激光器的解理腔面，并对其进行氩离子清洗，俄歇电子能谱（AES）分析显示氩离子清洗可以有效地清除GaAS表面的氧和碳等杂质。