Burn-in Effect Research Articles

A high-resolution, data-driven agent-based model of the housing market

This paper presents a complex, modular, 1:1 scale model of the Hungarian residential housing market. All of the 4 million households with their relevant characteristics and all of the flats with detailed attributes like size, state and neighbourhood quality are represented, based on empirical micro-level data. The model features transactions in the housing and rental markets, a construction sector, buy-to-let investors, credit markets, house price dynamics, a procyclical banking sector regulated by a macroprudential authority and exogenous macroeconomic environment. While these features increase the complexity considerably, they also make it possible to surpass existing tools, most importantly in two aspects. First, the granularity of the model enables much higher resolution and heterogeneity in the results, and second, the detailed mapping to empirical data makes it possible to run the simulations in prompt time with only minimal burn-in effects. Thus, the model enables the study of the impact of selected macroprudential, fiscal and monetary policies on the housing market in a more detailed and plausible way than in the case of the traditional analytical tools. After calibrating the model on Hungarian data, it managed to reproduce the key characteristics of the housing market even at disaggregated levels based on regions and the income deciles of the households. To demonstrate the model's practicality, we also present two applications, assessing the impact of construction cost shocks and family support measures on the housing market.

Burn-in effect in InGaP/GaAs HBT with intrinsically or extrinsically carbon doped base layer

InGaP/GaAs heterojunction bipolar transistors (HBTs) with intrinsically or extrinsically carbon doped base layers were grown by metal-organic chemical vapor deposition. Burn-in effect and the influence of thermal annealing at different temperatures on these devices were investigated. Results show that the intrinsically-carbon-doped HBTs demonstrate a higher current gain of 155 and a burn-in value of 24.0%, while the extrinsically-carbon-doped HBTs show a current gain of 92 and a burn-in value of 5.3%. Thermal annealing after exposing the base layer decreases the burn-in value from 24.0% to 5.7% and from 5.3% to 1.3% for intrinsically and extrinsically carbon doped HBTs, respectively, proved to be an effective method to eliminate the burn-in effect of HBT devices by hydrogen out diffusion. However, it also damages the base layer quality, leading to increased base recombination current and decreased current gain.

Revival of Insulating Polyethylenimine by Creatively Carbonizing with Perylene into Highly Crystallized Carbon Dots as the Cathode Interlayer for High-Performance Organic Solar Cells.

The development of new electron transporting layer (ETL) materials to improve the charge carrier extraction and collection ability between cathode and the active layer has been demonstrated to be an effective approach to enhance the photovoltaic performance of organic solar cells (OSCs). Herein, water-soluble carbon dots (CDs) as ETL material have been creatively synthesized by a vigorous chemical reaction between polyethylenimine (PEI) and 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) via a simple one-step hydrothermal method. Taking full advantage of the high electron transfer property of PTCDA and the work function (WF) reduction ability of PEI, CD gained high electron mobility due to its large π-conjugated area and reduced the WF of indium tin oxide (ITO) by 0.75 eV. As for the photovoltaic performance of devices, inverted OSCs based on CDs have achieved a high power conversion efficiency (PCE) of 17.35%, exhibiting no burn-in effect with no reduction in PCE after more than 4000 h of storage. The successful application of CDs in OPV has developed a new avenue for designing efficient ETL materials that benefits the photovoltaic performance of OSCs.

Progress in Understanding Degradation Mechanisms and Improving Stability in Organic Photovoltaics.

Understanding the degradation mechanisms of organic photovoltaics is particularly important, as they tend to degrade faster than their inorganic counterparts, such as silicon and cadmium telluride. An overview is provided here of the main degradation mechanisms that researchers have identified so far that cause extrinsic degradation from oxygen and water, intrinsic degradation in the dark, and photo-induced burn-in. In addition, it provides methods for researchers to identify these mechanisms in new materials and device structures to screen them more quickly for promising long-term performance. These general strategies will likely be helpful in other photovoltaic technologies that suffer from insufficient stability, such as perovskite solar cells. Finally, the most promising lifetime results are highlighted and recommendations to improve long-term performance are made. To prevent degradation from oxygen and water for sufficiently long time periods, OPVs will likely need to be encapsulated by barrier materials with lower permeation rates of oxygen and water than typical flexible substrate materials. To improve stability at operating temperatures, materials will likely require glass transition temperatures above 100 °C. Methods to prevent photo-induced burn-in are least understood, but recent research indicates that using pure materials with dense and ordered film morphologies can reduce the burn-in effect.

Long-term RF Burn-in Effects on Dielectric Charging of MEMS Capacitive Switches

This paper experimentally quantified the long-term effects of RF burn-in, in terms of burn-in and recovery times, and found the effects to be semipermanent. Specifically, most of the benefit could be realized after approximately 20 min of RF burn-in, which would then last for several months. Additionally, since similar effects were observed on both real and faux switches, the effects appeared to be of electrical rather than mechanical nature. These encouraging results should facilitate the application of the switches in RF systems, where high RF power could be periodically applied to rejuvenate the switches.

Highly reliable silicon carbide photodiodes for visible-blind ultraviolet detector applications

Highly efficient polytype 4H silicon carbide (4H-SiC) p–n diodes for ultraviolet (UV) light detection have been fabricated, characterized, and exposed to high-intensity mercury lamp irradiation (up to 17 mW/cm2). The behavior of the photocurrent response under UV light irradiation using a low-pressure mercury UV-C lamp (4 mW/cm²) and a medium-pressure mercury discharge lamp (17 mW/cm²) has been studied. We report on long-term UV photoaging tests performed for up to 22 mo. Results demonstrate the robustness of SiC photodiodes against UV radiation. The devices under test showed an initial burn-in effect, i.e., the photocurrent response dropped by less than 5% within the first 40 h of artificial UV aging. Such burn-in effect under UV stress was also observed for previously available polytype 6H silicon carbide (6H–SiC) p–n photodetectors. After burn-in, no measurable degradation has been detected, which makes the devices excellent candidates for high irradiance UV detector applications.

Research and discussion on the lock-in threshold variation of ring laser gyro

The lock-in threshold can be obtained by reducing the rotation rate. The lock-in threshold obtained using this method is inconsistent with the angle random walk derived from Allan variance. A dynamic burn-in grating model is proposed. The burn-in effect happens in the mirror not only in the standing wave state, but also in the traveling wave state, and it responds dynamically to beat frequency, which is different from previous research results. It can be derived that the lock-in threshold increases with the decrease of rotation rate for this model, and many puzzling phenomena of the ring laser gyro can be explained.

Burn-in considering yield loss and reliability gain for integrated circuits

This paper presents burn-in effects on yield loss and reliability gain for a lifetime distribution developed from a negative binomial defect density distribution and a given defect size distribution, after assuming that the rate of defect growth is proportional to the power of the present defect size. While burn-in always results in yield loss, it creates reliability gain only if either defects grow fast or the field operation time is long. Otherwise, burn-in for a short time could result in reliability loss. The optimal burn-in time for maximizing reliability is finite if defects grow linearly in time and is infinite if defects grow nonlinearly in time. The optimal burn-in time for minimizing cost expressed in terms of both yield and reliability increases in the field operation time initially but becomes constant as the field operation time is long enough. It is numerically shown that increasing mean defect density or defect clustering increases the optimal burn-in time.

High-Current-Gain Direct-Growth GaN/InGaN Double Heterojunction Bipolar Transistors

We report high-current-gain n-p-n GaN/InGaN double-heterojunction bipolar transistors (DHBTs) using a direct-growth fabrication processing approach. The impact of the indium composition in the base layer was studied, and a burn-in effect using a constant-base-current stressing method was observed. We found that DHBTs with higher indium composition in the InGaN base layer may help reduce the base resistance and lower the surface recombination current but may result in higher bulk recombination current. A device burn-in effect was also studied. The postprocessing current stressing step helps increase free-hole concentration in the base, reduce the bulk recombination current, and enhance the current gain. As a result, a direct-growth GaN/In0.03Ga0.97N DHBT with a peak current gain of 105 and a collector current density > 6.5 kA/cm2 was demonstrated on a sapphire substrate.

Reply to “Comments on “Observations on Component Infant Mortality and Burn-In Effectiveness””

In the paper under discussion, the Van der Pol article referenced by this author and also by the commentator is a study of a large number of devices used in commercial products where both the long term reliability in system application (field reliability) and long term life test were compared to sample burn-in testing. The authors of this reference found that life test data and system reliability were both well fitted to Weibull distribution. The formulae in the IEEE forum article are based on an empirical fit to this very large number of experimental data points. These are not assumptions but simply an empirical model well grounded in an extensive experimental data set. This author does not assert that a single failure mechanism is appropriate to a complete explanation of infant mortality in integrated circuits. I concur that many failure mechanisms actually apply with different failure characteristics (best detected by failure analysis of infant mortals) and different acceleration.

Comments on "Observations on component infant mortality and burn-in effectiveness

This paper presents the comments of the author on the work of Mr. Cooper (2008) by pointing out two concerns: First, the discussion of burn-in, and the tone of one of the major references (van der Pol et al. (1998)), would lead one to believe that burn-in is the only screen currently or commonly used to identify infant mortality or to detect substandard components. Second, it appears that Cooper's assumptions regarding acceleration factors may be suitable in cases where burn-in is the only screen in use, where the defects are susceptible to the burn-in stresses, and where only a limited number of different failure modes are present.

Observations on Component Infant Mortality and Burn-In Effectiveness

The following concepts are discussed: burn-in effectiveness, component failure distributions, early life distribution, early life failures, infant mortality.

Total Dose Effects in Op-Amps With Compensated Input Stages

This paper discusses total dose damage in operational amplifiers with compensated input stages. The impact of this design approach on unit-to-unit variability of radiation damage is examined, along with hardness assurance methods that can be used to bound the radiation behavior. Data is included for an unusually large sample (100 devices) of one device type. Half of those devices were subjected to burn-in before irradiation to investigate the effect of burn-in on radiation response.

Elimination of Burn-in Effect in Metal–Organic Chemical Vapor Deposition Grown InGaP/GaAs Heterojunction Bipolar Transistors by Multistep In situ Annealing

The burn-in effect in InGaP/GaAs heterojunction bipolar transistors (HBTs) grown by metal–organic chemical vapor deposition was eliminated by a multistep in situ annealing process. The presence of hydrogen in the HBT base region is the origin of the burn-in effect. An in situ annealing process was conducted during the growth of the emitter cap to reduce the concentration of hydrogen incorporated in the base region. However, diffusion may cause hydrogen to be retrapped in the base and emitter regions during the growth of the residual structure after annealing. In order to eliminate the burn-in effect, a multistep in situ annealing process was evaluated for its ability to overcome the indiffusion of hydrogen. In this investigation, a burn-in effect of less than 5% for metal–organic chemical vapor deposition grown HBTs was achieved without noticeably degrading the device performance by four-step in situ annealing.

Role of Annealing in Constant Period of Voltage Stress on the Burn-in Effect Suppression of InGaP/GaAs Heterojunction Bipolar Transistors

Rapid thermal annealing (RTA) is proved to be more efficient in dissociating hydrogen complexes than using a constant period of voltage stress (CPVS). Without waiting for the bond breaking of complexes by minority carrier injection, RTA favors the critical base–emitter voltage (VBE) responsible for the occurrence of burn-in (BI) from 1.75 to 1.4 V and thus assists CPVS in reducing VBE by about 25% used in BI suppression. Besides eliminating the BI, the sample first prepared by RTA and followed by CPVS has larger base and collector current densities at VBE>1.1 V and reaches 6 times those at VBE>1.3 V compared with the sample only using by CPVS.

Correlation between the base–emitter interface crystalline quality and the current gain in InGaP/GaAs HBTs grown by MOVPE

We demonstrated that the InGaP emitter ledge passivation in InGaP/GaAs heterojunction bipolar transistor (HBT) could suppress the recombination components in I B induced by the extrinsic base surface and the defects activated by the current stress. Similar suppression of I B by the current stress was found in unpassivated HBT with the 2 min growth interruption at the base–emitter interface under PH 3 partial pressure and we attributed this to the existence of an intermediate layer at the base–emitter interface that would improve the interface crystalline quality and reduce the recombination component of I B induced by defects at the base–emitter edge. Unpassivated HBT with the shorter post-growth annealing in time in hydrogen atmosphere, however, showed the increase in the current gain β with the current stress because of the burn-in effect rather than the decrease in β due to the increase of I B induced by defects.

A change-point analysis for modeling incomplete burn-in for light displays

In testing display devices such as Plasma Display Panels (PDPs), the observed degradation in luminosity can exhibit an unstable period due to incomplete burn-in during the manufacturing process. We introduce a log-linear model with random coefficients and a change point to describe the nonlinear degradation path. The change point represents the time at which the burn-in period has finished and the degradation in the luminosity changes to a slower and more stable rate. The inference procedure for the lifetime distribution is based on maximum likelihood estimators and results indicate that reliability estimation can be improved substantially by using the change-point model to account for product burn-in effects. An example based on laboratory tests of PDPs helps to illustrate the procedure.

Burn-in policies for products having dormant states

Many systems might have a long time dormant period, during which the systems are not operated. For example, most building services products are installed while a building is constructed, but they are not operated until the building is commissioned. Warranty terms for such products may cover the time starting from their installation times to the end of their warranty periods. Prior to the commissioning of the building, the building services products are protected by warranty although they are not operating. Developing optimal burn-in policies for such products is important when warranty cost is analysed. This paper considers two burn-in policies, which incur different burn-in costs, and have different burn-in effects on the products. A special case about the relationship between the failure rates of the products at the dormant state and at the operating state is presented. Numerical examples compare the mean total warranty costs of these two burn-in policies.

TWO-LEVEL BURN-IN FOR RELIABILITY AND ECONOMY IN REPAIRABLE SERIES SYSTEMS HAVING INCOMPATIBILITY

When a system is assembled from components, incompatibility often occurs as a result of the assembly process. The ability to quantify incompatibility is very important for making burn-in decisions because the goal of system burn-in is to minimize the incompatibility factor. In the past, incompatibility has been only partially represented in the system prediction models because it was assumed that assembly had no effect on the components. This paper presents a more accurate model for system prediction by allowing for the possibility that, in some cases, assembly adversely affects the components. After applying a superposition of delayed renewal processes and a nonhomogeneous Poisson process for modeling times between system failures, we derive and analyze the effects of component and system burn-in on the system cost and performance. Examples are included to demonstrate how to determine optimal component and system burn-in times simultaneously based on an equivalent problem formation and nonlinear programming.

Suppression of the burn-in effect in InGaP/GaAs heterojunction bipolar transistors by constant period of voltage stress

Two significantly abrupt increases of dc current gain (β) at the opposite extremes of base-emitter voltages (Vbe) linked by a relatively slight increase of β in the range of 1.25⩽Vbe⩽1.75 V are found in InGaP/GaAs heterojunction bipolar transistors (HBT’s). It has been proved that the burn-in effect directly causes the second abrupt increase of β occurring at Vbe>1.75 V instead of elsewhere. In addition, choosing Vbe>1.75 V, a higher base-emitter voltage results in a faster increase rate with improvement in current gain transient. Based on these observations, a constant period of voltage stress (CPVS) with Vbe=2.0 V and Vce=3.0 V for 5 min with a specific choice of Vbe>1.75 V (the voltage range corresponding to the second abrupt increase of β) is thus applied to promote the electrical performance of HBT’s. After applying a CPVS, the burn-in effect is substantially suppressed without showing any second abrupt increase of current gain. Although the current measured under both reverse and forward biases is greatly reduced for the base-emitter junction, a CPVS slightly degrades the electrical properties of a base-collector junction. Also, it has been proved that bulk recombination, rather than the surface recombination current, the base contact recombination, or the space-charge recombination, is the dominant base current component causing the burn-in effect. The electrical improvement of the base-emitter junction is due to the annihilation of H-related traps in the base region after a CPVS. Once H− ions form, we propose that these ions are too fast to drift toward the base-collector junction under the reverse bias of the base-collector voltage. After migration through the extrinsic base region, H− ions are supposed to be trapped near the base-collector space region, which results in the degradation of the base-collector junction after a CPVS.