Lifetime Extrapolation Research Articles

Cost effectiveness of pembrolizumab plus lenvatinib compared with chemotherapy for treating previously treated advanced endometrial cancer in Sweden

Objective Pembrolizumab plus lenvatinib was recently approved for the treatment of advanced or recurrent endometrial carcinoma in women with disease progression on or following prior treatment with a platinum‑containing therapy in any setting, and who are not candidates for curative surgery or radiation (KEYNOTE-775/Study-309; NCT03517449). The objective was to assess the cost effectiveness of pembrolizumab plus lenvatinib compared with chemotherapy from a Swedish healthcare perspective. Materials and methods A lifetime partitioned-survival model with three health states (progression free, progressed disease, death) was constructed. Chemotherapy was represented by paclitaxel or doxorubicin. Overall survival, progression-free survival, time on treatment, and utility data were obtained from KEYNOTE-775 (database lock: March 1, 2022). Costs (in 2020 Swedish Krona [SEK]) included drug acquisition and administration, health state, end of life, adverse event management, subsequent treatment, and societal (scenario analysis). Outcomes were calculated as quality-adjusted life-years (QALY) and life-years. Model results were presented as incremental cost-effectiveness ratios for all-comers, patients with proficient mismatch repair tumors, and deficient mismatch repair tumors. Deterministic and probabilistic sensitivity analyses were conducted. Results Pembrolizumab plus lenvatinib is a cost-effective treatment when compared with chemotherapy, with estimated deterministic and probabilistic incremental cost-effectiveness ratios of SEK 795,712 and 819,757 per QALY gained. Pembrolizumab plus lenvatinib was associated with a large incremental QALY and life-year gain per person versus chemotherapy over the model time horizon (1.49 and 1.76). Limitations Time-to-event data were incomplete and semiparametric and parametric curves were utilized for lifetime extrapolation. Willingness-to-pay thresholds, costs, and utility weights vary by country, which would vary the treatment’s cost effectiveness in different countries. Conclusions This partitioned survival analysis suggests that pembrolizumab plus lenvatinib is cost effective compared with chemotherapy in Sweden for women with advanced or recurrent endometrial carcinoma following previous systemic therapy. Results were robust to mismatch repair status and to changes in parameters/assumptions.

A Universal Scaling Formulation of the Generalized Peck’s Equation for Corrosion Limited Lifetime in Self-Heated ICs

Since the early 1980s, the highly accelerated stress test in conjunction with conventional Temperature-Humidity-Bias testing has been the industry-standard method for interpreting relative humidity (RH) and temperature (T) dependent failure modes in non-hermetically packaged ICs, solar modules, and other electronic components. In recent years, however, testing requirements based on JEDEC standards and the corresponding lifetime extrapolation to end-use conditions using Peck’s equation have been criticized as overly conservative for modern self-heated logic/power ICs. In practice, the self-heated ICs correlate RH, and T in a way that is not explicitly accounted for by Peck’s equation. In this study, we investigate the IC lifetime due to electrochemical failures – Cu-Al bond wire corrosion – by considering the effects of ambient RH, T, duty cycle, and self-heating temperature rise using an integrated self-consistent finite element-based Multiphysics model and propose a generalized Peck’s equation for self-heated ICs. Our study reveals how the asymmetry between On and Off-state heating leads to dramatic suppression of the effective RH experienced by an integrated circuit and, most importantly, identifies that the corrosion of Cu-Al bond wire occurs in spikes during the on-off transition when both RH and T are high. The generalized Peck’s equation also predicts an elegant scaling relationship among the fundamental variables associated with a self-heated IC lifetime. The prediction is validated by experimental lifetime data from self-heated IC published in the literature. The experimental validation of the physics-informed generalized Peck’s equation suggests the possibility of more accurate (and optimistic) lifetime predictions of modern ICs and solar modules.

Lifetime cost-effectiveness simulation of once-weekly exenatide in type 2 diabetes: A cost-utility analysis based on the EXSCEL trial

AimsThe Exenatide Study of Cardiovascular Event Lowering (EXSCEL) trial assessed once-weekly exenatide (EQW) vs. placebo, added to usual care in 14,752 patients with type 2 diabetes mellitus (Clinicaltrials.gov: NCT01144338). We assessed the lifetime cost-effectiveness of adding EQW vs. usual care alone from a healthcare perspective. MethodsMedical resource use and EQ-5D utilities were collected throughout the study. Within-trial results were extrapolated to a lifetime horizon using the UK Prospective Diabetes Study Outcomes Model version 2 (UKPDS-OM2), predicting predict cardiovascular and microvascular events. Cost-effectiveness was evaluated separately for US and UK settings, with outcomes measured in quality-adjusted life-years (QALYs). ResultsEQW plus usual care gained 0.162 QALYs at an additional cost of $41,545/patient, compared with usual care in a US setting. The incremental cost-effectiveness ratio (ICER) was $259,223/QALY. In a UK setting, the QALY gain was 0.151 at an additional cost of £6357: an ICER of £42,589/QALY. Sensitivity analyses ranged between $34,369–$269,571 and £3430–£46,560 per QALY gained. ConclusionsIn a lifetime extrapolation, adding EQW to usual care increased QALYs and costs compared with usual care alone. The base-case ICERs exceeded the commonly-cited cost-effectiveness thresholds of $100,000/QALY and £20,000/QALY. However, ICERs were considerably lower in some subgroups, and in sensitivity analyses.

Cost-effectiveness of bilateral vs. single internal thoracic artery grafts at 10 years.

AimsUsing bilateral internal thoracic arteries (BITAs) for coronary artery bypass grafting (CABG) has been suggested to improve survival compared to CABG using single internal thoracic arteries (SITAs) for patients with advanced coronary artery disease. We used data from the Arterial Revascularization Trial (ART) to assess long-term cost-effectiveness of BITA grafting compared to SITA grafting from an English health system perspective.Methods and resultsResource use, healthcare costs, and quality-adjusted life years (QALYs) were assessed across 10 years of follow-up from an intention-to-treat perspective. Missing data were addressed using multiple imputation. Incremental cost-effectiveness ratios were calculated with uncertainty characterized using non-parametric bootstrapping. Results were extrapolated beyond 10 years using Gompertz functions for survival and linear models for total cost and utility. Total mean costs at 10 years of follow-up were £17 594 in the BITA arm and £16 462 in the SITA arm [mean difference £1133 95% confidence interval (CI) £239 to £2026, P = 0.015]. Total mean QALYs at 10 years were 6.54 in the BITA arm and 6.57 in the SITA arm (adjusted mean difference −0.01 95% CI −0.2 to 0.1, P = 0.883). At 10 years, BITA grafting had a 33% probability of being cost-effective compared to SITA, assuming a cost-effectiveness threshold of £20 000. Lifetime extrapolation increased the probability of BITA being cost-effective to 51%.ConclusionsBITA grafting has significantly higher costs but similar quality-adjusted survival at 10 years compared to SITA grafting. Extrapolation suggests this could change over lifetime.

Predicting lifetime of optical components with Bayesian inference.

Virtually all optical materials degrade over time when they are used in high average power or intensity optical systems. Extrapolation of optical components lifetime is crucial in such applications in order to avoid downtime or project failure. Measurements of the laser-induced damage threshold (LIDT) fatigue are usually done using the so-called S-on-1 test described in the ISO 21254-2 standard. The standard, however, suggests only rudimentary techniques for extrapolating LIDT, which are rarely used in practice, therefore, the goal of this work was to provide a framework for analyzing LIDT fatigue data using well established methods of Bayesian statistics. Numerical S-on-1 experiments (assuming constant fatigue) were performed for cases of online detection, interval detection and offline detection. Appropriate lifetime distributions were determined and used to fit simulated data taking into consideration data censoring. Credible intervals of lifetime predictions were determined using Markov chain Monte Carlo (MCMC) technique and compared with results from multiple experiments. The Bayesian lifetime analysis method was compared with technique described in the ISO 21254-2 standard for cases of low and high defect densities. Finally, the outlined extrapolation technique was applied to extrapolate lifetime of HR dielectric mirror.

Accelerated Testing of SiC Power Devices under High-Field Operating Conditions

Power metal-oxide-semiconductor field-effect transistors (MOSFETs) experience conditions of high field during normal operation. During switching conditions, unexpected transient events may occur which force devices into avalanche or short circuit conditions. Moreover, silicon carbide devices typically experience higher fields in the gate oxide and drift regions than comparable Si devices due to channel and drift property differences. A summary of SiC MOSFET reliability and ruggedness test results are reported here. Reliability tests under high field conditions: positive-bias and negative-bias temperature instability (PBTI, NBTI) to examine threshold stability; time-dependent dielectric breakdown (TDDB) for gate oxide lifetime extrapolation; high-temperature reverse bias (HTRB); and HTRB testing under high neutron flux to determine terrestrial neutron single-event burnout (SEB) rates. High-power ruggedness evaluation is presented for SiC MOSFETs under forced avalanche conditions (unclamped inductive switching (UIS)) and under short-circuit operation to bound device safe operating areas. Overall results demonstrate the intrinsic reliability of SiC MOSFETs.

Model for the Prediction of the Lifetime and Energy Yield of Methyl Ammonium Lead Iodide Perovskite Solar Cells at Elevated Temperatures.

With the realization of highly efficient perovskite solar cells, the long-term stability of these devices is the key challenge hindering their commercialization. In this work, we study the temperature-dependent stability of perovskite solar cells and develop a model capable of predicting the lifetime and energy yield of perovskite solar cells outdoors. This model results from the measurement of the kinetics governing the degradation of perovskite solar cells at elevated temperatures. The individual analysis of all key current-voltage parameters enables the prediction of device performance under thermal stress with high precision. An extrapolation of the device lifetime at various European locations based on historical weather data illustrates the relation between the laboratory data and real-world applications. Finally, the understanding of the degradation mechanisms affecting perovskite solar cells allows the definition and implementation of strategies to enhance the thermal stability of perovskite solar cells.

Voltage-Dependent Activation Energy Maps for Analytic Lifetime Modeling of NBTI Without Time Extrapolation

To enable MOSFETs lifetime extrapolation of up to 10 years, bias temperature instability (BTI) is commonly accelerated via increased stress voltage and increased temperature. We demonstrate that BTI can be described by a unique activation energy map including the voltage and temperature dependence of stress and recovery and use capture and emission time maps to model the time dynamics responsible for the threshold voltage shift of BTI. Based on this approach, we present a new measurement technique, further called temperature-accelerated measure-stress-measurements (TA-MSM) enabling lifetime modeling of BTI without any time extrapolation. We show the application of this technique to simulate standard qualification measurements, fast wafer-level reliability measurements as well as the degradation after ac and dc burn-in stress. In addition, we show that the TA-MSM technique is a valuable tool for the study of the permanent component and the recently discovered reverse recovery effect.

Comphy — A compact-physics framework for unified modeling of BTI

Metal-oxide-semiconductor (MOS) devices are affected by generation, transformation, and charging of oxide and interface defects. Despite 50 years of research, the defect structures and the generation mechanisms are not fully understood. Most light has been shed onto the charging mechanisms of pre-existing oxide defects by using the non-radiative multi-phonon theory. In this work we present how the gist of physical models for pre-existing oxide defects can be efficiently abstracted at a minimal loss of physical foundation and accuracy. Together with a semi-empirical model for the generation and transformation of defects we establish a reaction-limited framework for unified simulation of bias temperature instabilities (BTI). The applications of the framework we present here cover simulation of BTI for negative (NBTI) and positive (PBTI) gate voltages, life time extrapolation, AC stress with arbitrary signals and duty cycles, and gate stack engineering.

A Study on the Life-Time Assessment Ways and Various Failure Types of 154 kV Porcelain Insulators Installed in South Korea

In this study, we investigated 154-kV porcelain insulators with various failure types and discussed the causes of the failures. In South Korea, 1,223,538 154 kV porcelain insulators (produced by a foreign company) are in active service in 2017, installed in overhead power transmission lines. Among them, 797,659 (65.19%) have been used over 30 years in active service. Porcelain insulators employed in transmission lines need to exhibit a high electrical resistance, mechanical strength, stability, and ability to maintain satisfactory performance under various environments. In this study, a life-time assessment strategy is proposed for the 154 kV porcelain insulators according to the operational circumstances. The life-time extrapolation of porcelain insulators in 154-kV transmission lines is very challenging, owing to the complex aging process. As the first step of the life-time extrapolation, we characterized the failure types. Various factors such as temperature, rain, dust, acids, corrosion, vibrations, and mechanical and electrical stresses, over a long period of time can lead to various types of failures in porcelain insulators.

A Novel Algorithm for Lifetime Extrapolation, Prediction, and Estimation of Emerging PV Technologies

AbstractAccurate determination of the lifetime of novel hybrid and organic solar cells is often rather challenging due to the very dynamic behavior of such cells over time and ageing curves with shapes of varying nature. Therefore, in order to accurately and reproducibly determine the lifetime of photovoltaic devices with such a behavior, a novel elaboration algorithm is developed, which enables automatic smoothing, filtering, and extrapolation of the real lifetime data and reproducible determination of the lifetime parameters defined in the International Summit on OPV Stability guiding standards. The algorithm is also capable of predicting the lifetime of devices, not tested until the end of sample life, given that there is sufficient number of measured data points to perform reliable extrapolation of ageing curves (to a limited time frame). The algorithm is discussed in detail and a range of examples for different lifetime data are presented.

Cost-effectiveness of enzyme replacement therapy with alglucosidase alfa in adult patients with Pompe disease

BackgroundPompe disease is a rare, progressive, metabolic disease, and the first treatable inheritable muscle disorder. Enzyme replacement therapy (ERT) with alglucosidase alfa is disease specific and the only medicinal product authorized for the treatment of Pompe disease. Costs of ERT are very high as for most orphan drugs. This study investigates the cost-effectiveness of ERT compared to supportive treatment in adult patients with Pompe disease.MethodsSurvival probabilities were estimated from an international observational dataset (n = 283) using a time-dependent Cox model. Quality of life was estimated on a Dutch observational dataset using a previously developed conceptual model which links clinical factors to quality of life. Costs included costs of ERT, costs of drug administration and other healthcare costs. Cost-effectiveness was estimated using a patient-level simulation model (n = 90), synthesising the information from underlying models for survival, quality of life and costs. The cost-effectiveness model estimated the (difference in) lifetime effects and costs for both treatments. Two scenarios were modelled: (1) a worse case scenario with no extrapolation of the survival gain due to ERT beyond the observed period (i.e. from 10 years onwards); and (2) a best case scenario with lifetime extrapolation of the survival gain due to ERT. Effects were expressed in (quality adjusted) life years (QALYs). Costs were discounted at 4.0% and effects at 1.5%.ResultsSubstantial increases in survival were estimated – discounted incremental life years of ERT ranged from 1.9 years to 5.4 years in the scenarios without and with extrapolation of survival gains beyond the observed period. Quality of life was also significantly better for patients receiving ERT. Incremental costs were considerable and primarily consisted of the costs of ERT. Incremental costs per QALY were €3.2 million for scenario 1 and €1.8 million for scenario 2.ConclusionsThe availability of extended, prospectively collected, longitudinal observational data on the most important input parameters required to construct a cost-effectiveness model is quite exceptional for orphan diseases. The cost-effectiveness model showed substantial survival gains from ERT. Despite these substantial gains, ERT was not cost-effective in the treatment of adult Pompe disease because of the high cost of treatment.

Lifetime predictions of exposed geotextiles and geomembranes

A very frequently asked question regarding all types of geosynthetics is, ‘How long will they last?’ This paper answers the question for exposed geotextiles and geomembranes, assuming that they were properly designed and installed. Furthermore, it compares these new results to the earlier lifetime prediction results of a covered geomembrane. Nonexposed (or covered) lifetime conditions for a 1.5 mm thick high-density polyethylene (HDPE) geomembrane have previously been evaluated and published. Landfill incubation devices at four elevated temperatures of 85, 75, 65 and 55°C were used in the prediction in order to reach 50% of retained strength and elongation. Considering the three stages of (i) depletion of antioxidants, (ii) induction time, and (iii) 50% reduction in mechanical properties, the lifetime extrapolation was made down to 20°C. The 50% reduction value (called halflife throughout the paper) for this geomembrane under these conditions was approximately 450 years. Since the laboratory incubation times took 12 years, other nonexposed geosynthetics were not evaluated under the supposition that the covered situation is generally a moot point for most geosynthetics in their customary applications. For exposed (or uncovered) geosynthetics, however, the situation is quite different. Ultraviolet radiation, elevated temperature and full oxygen are available, which shortens the service lifetime, but how much? For evaluation of this situation, the authors utilized laboratory ultraviolet fluorescent tube weathering devices, as per ASTM D7238, for incubation purposes. Seven different geotextiles and five different geomembranes were evaluated. Each material was incubated at 80, 70 and 60°C until a 50% reduction of strength and elongation occurred. The data was then extrapolated down to 20°C for laboratory halflife values and for comparison with the nonexposed condition. The ratio of nonexposed to exposed lifetime for HDPE geomembranes is approximately seven. The calculations for the 12 exposed geosynthetics then progressed to using site-specific radiation to obtain an equivalent field halflife. Phoenix, Arizona, conditions are illustrated although the procedure is applicable worldwide. Halflife predictions for the geotextiles vary from a few months for the needle punched nonwovens to up to 10 years for monofilaments and high antioxidant formulated products. Results for geomembranes vary from 47 to 97 years, with HDPE being the highest. These exposed halflife results (which took 12 years of laboratory incubation to achieve) are felt to be most interesting and are presented for the first time to an international audience.

Reliability Analysis of LPCVD SiN Gate Dielectric for AlGaN/GaN MIS-HEMTs

In this paper, we investigate Low Pressure Chemical Vapor Deposition (LPCVD) SiN as a gate isolation material for AlGaN/gallium nitride (GaN) MIS-high electron mobility transistor power transistors. We compared the dielectric failure by forward-biased constant-current stress time-dependent dielectric breakdown measurements and statistical Weibull analysis. Several 4” AlGaN/GaN-on-Si wafers have been processed with different gate isolations and processes. Our investigation includes the dependence of the dielectric breakdown on the process flow (influence of dry etch), the thickness of the dielectric (12–20 nm), the area scaling, and the gate electrode, where we also consider the recently presented poly-silicon electrode. Additionally, we show the influence of the current density through the gate on the charge-to-breakdown characteristics as well as the influence of the temperature on the breakdown behavior. Using the poly-silicon electrode and 20 nm LPCVD SiN as gate isolation, we achieved a charge-to-breakdown of ${Q}_{\text {BD, 10}~\text {mA}/\text {cm}^{2}} ={3.7} ~ \text {kC}/\text {cm}^{{2}}$ at $\text {T} = {130} {^{\circ }}\text {C}$ for ${j} = {10} ~ \text {mA}/\text {cm}^{{2}}$ . A 20-years lifetime (100 ppm, $\text {T} = {130} {^{\circ }}\text {C}$ ) extrapolation for a scaled area of ${0.2} ~ \text {mm}^{{2}}$ ( $\buildrel \wedge \over = {W}_{G} = {100} ~ \text {mm}$ ) leads to a positive gate voltage of ${V}_{\text {G}} = {9.4} ~ \text {V}$ .

Surgery for degenerative cervical myelopathy: a patient-centered quality of life and health economic evaluation

Background ContextDegenerative cervical myelopathy (DCM) represents the most common cause of non-traumatic spinal cord impairment in adults. Surgery has been shown to improve neurologic symptoms and functional status, but it is costly. As sustainability concerns in the field of health care rise, the value of care has come to the forefront of policy decision-making. Evidence for both health-related quality of life outcomes and financial expenditures is needed to inform resource allocation decisions. PurposeThis study aimed to estimate the lifetime incremental cost-utility of surgical treatment for DCM. Design/SettingThis is a prospective observational cohort study at a Canadian tertiary care facility. Patient SampleWe recruited all patients undergoing surgery for DCM at a single center between 2005 and 2011 who were enrolled in either the AOSpine Cervical Spondylotic Myelopathy (CSM)-North America study or the AOSpine CSM-International study. Outcome MeasuresHealth utility was measured at baseline and at 6, 12, and 24 months following surgery using the Short Form-6D (SF-6D) health utility score. Resource expenditures were calculated on an individual level, from the hospital payer perspective over the 24-month follow-up period. All costs were obtained from a micro-cost database maintained by the institutional finance department and reported in Canadian dollars, inflated to January 2015 values. MethodsQuality-adjusted life year (QALY) gains for the study period were determined using an area under the curve calculation with a linear interpolation estimate. Lifetime incremental cost-to-utility ratios (ICUR) for surgery were estimated using a Markov state transition model. Structural uncertainty arising from lifetime extrapolation and the single-arm cohort design of the study were accounted for by constructing two models. The first included a highly conservative assumption that individuals undergoing nonoperative management would not experience any lifetime neurologic decline. This constraint was relaxed in the second model to permit more general parameters based on the established natural history. Deterministic and probabilistic sensitivity analyses were employed to account for parameter uncertainty. All QALY gains and costs were discounted at a base of 3% per annum. Statistical significance was set at the .05 level. ResultsThe analysis included 171 patients; follow-up was 96.5%. Mean age was 58.2±12.0 years and baseline health utility was 0.56±0.14. Mean QALY gained over the 24-month study period was 0.139 (95% confidence interval: 0.109–0.170, p<.001) and the mean 2-year cost of treatment was $19,217.82±12,404.23. Cost associated with the operation comprised 65.7% of the total. The remainder was apportioned over presurgical preparation and postsurgical recovery. Three patients required a reoperation over the 2-year follow-up period. The costs of revision surgery represented 1.85% of the total costs. Using the conservative model structure, the estimated lifetime ICUR of surgical intervention was $20,547.84/QALY gained, with 94.7% of estimates falling within the World Health Organization definition of “very cost-effective” ($54,000 CAD). Using the more general model structure, the estimated lifetime ICUR of surgical intervention was $11,496.02/QALY gained, with 97.9% of estimates meeting the criteria to be considered “very cost-effective.” ConclusionsSurgery for DCM is associated with a significant quality of life improvement. The intervention is cost-effective and, from the perspective of the hospital payer, should be supported.

Application of the defect clustering model for forming, SET and RESET statistics in RRAM devices

The choice of the right statistical model to describe the distribution of switching parameters (forming, SET and RESET voltages) is a critical requirement for RRAM, as it is used to analyze the worst case scenarios of operation that have to be accounted for while designing the cross-bar array structures, so as to ensure a robust design of the circuit and reliable data storage unit. Several models have been proposed in the recent past to characterize the voltage variations in VFORM, VSET and VRESET using the percolation framework. However, most of these models assume defect generation to be a Poisson process and apply the standard Weibull distribution for parameter extraction and lifetime extrapolation. Recent dielectric breakdown studies both at the front-end as well as back-end have shown that the Weibull statistics does not describe the stochastic trends well enough, more so in downscaled structures at the low and high percentile regions given the possibility of defect clustering which is either physics-driven or process quality-driven. This phenomenon of defect clustering is all the more applicable in the context of resistive random access memory (RRAM) devices, as switching occurs repeatedly at ruptured filament locations where defect clusters pre-exist. This study examines the validity of the clustering model for RRAM switching parameter statistics (time/voltage to FORM, SET and RESET) and presents a physical picture to explain the origin of clustering in RRAM. A large set of data from various published studies has been used here to test the suitability and need for a clustering model based reliability assessment. Dependence of the clustering factor on temperature, voltage, device area, dielectric microstructure and resistance state has also been examined.

Isothermal and cyclic oxidation behaviour of hot-pressed MSi2 compounds (with M = V, Ti, Cr)

The oxidation resistance of MSi2 compounds with M = V, Ti, Cr was investigated from 450 to 950 °C in air under isothermal and cyclic conditions. Vanadium, chromium and titanium disilicide were not subjected to the pest phenomenon at 650 °C over 800 1-h cycles. The results demonstrated very low weight gains regardless of the testing conditions. Oxidation tests were also performed over long duration (1000 h) to identify the oxidation products. The MSi2 compounds were all subjected to the simultaneous oxidation of M and Si despite the formation of a protective silica scale. Increasing the duration of oxidation enhanced the protective properties of the silica scale. Therefore, short-term measurements (by thermogravimetry) did not allow an extrapolation of the MSi2 lifetime. The formation of molten V2O5 induced a higher oxidation rate of VSi2 and delayed the establishment of the protective silica scale compared with CrSi2 and TiSi2.

Degradation Model of a Linear-Mode LED Driver and its Application in Lifetime Prediction

The degradations of a linear-mode LED driver under different voltage stresses are studied. This driver provides a constant current when the output voltage is biased greater than a knee-point voltage. During the stress tests, the knee-point voltage is found to increase due to the aging of the output transistor in the driver. As the knee-point voltage exceeds the applied output voltage, the output current cannot be maintained as constant, and the driver is considered failure. Therefore, the lifetime of the driver can be estimated from the knee-point voltage degradation. In this paper, a lifetime extrapolation method is proposed based on an internal circuit degradation mechanism. The correlations between the degradation model parameters and the applied stress are deduced, and the lifetime of the driver under different voltage stresses can be predicted with this correlation.

Reliability characterization of silicon-based germanium waveguide photodetectors

A silicon-based germanium waveguide photodetector was demonstrated and its reliability related items were investigated. For different reverse biases, the slopes of the dark current increment versus stress time curves were first found to be the same, which made the lifetime extrapolation feasible. The lifetime of the photodetector under different bias was predicted by using a simple extrapolation method. In order to maintain the 10-year lifetime of the photodetector, the bias voltage should be kept lower than − 3 V . For the first time, the degradation mechanism under stress biases was analyzed in detail by the reaction-diffusion (RD) model. The experimental results agree well with the theoretical derivation based on RD model.

Analytical model for anomalous Positive Bias Temperature Instability in La-based HfO2 nFETs based on independent characterization of charging components

PBTI improvement in HfO2 nFETs achieved by a controlled insertion of La.Anomalous negative ΔVTH due to charge exchange between high-k and metal gate.Anomalous and conventional PBTI components are decoupled and studied separately.Analytical model including both components for lifetime extrapolation is presented. Incorporation of rare earth capping layers in the gate stack is an effective technique to tune the threshold VTH voltage of advance CMOS technologies. Furthermore, a reduction of the positive VTH drift (instability) has been reported for rare-earth doped nFETs under positive gate bias stress at high temperature. However, a non-optimized process can lead to an anomalous VTH behavior. We demonstrate that two independent components are responsible for this anomalous behavior which can be decoupled, individually studied, and then projected for meaningful lifetime extrapolations.