Abstract
Purpose
The aim of this paper is to provide some specific information on the effects of DC voltage stress on the current, rise time (Tr) and fall time (Tf), at switching between on and off state of power n‐MOSFET devices.
Design/methodology/approach
A constant positive electrical stress voltage technique is used to study the devices in this work by giving the gate a positively bias with respect to source and a short circuit of the drain with the grounded source. Voltage stress is gradually increased by automatic 1 V step until it reaches the max tolerated value by the gate dielectric (70 V for device studied in this paper). Response of the device for electrical stress was measured for different doses (stress time).
Findings
The experimental results show that the rise time increases the beginning of stress dose and then it almost stabilises with time, while fall time decreases at first and then starts to increase for higher stress time. The modification of the device switching time parameters were associated to positive oxide charge and interface state Si/SiO2 effects.
Originality/value
This paper offers new information concerning a very important field in microelectronic devices where the switching speed of the components becomes a major requirement. The technique used to improve the device speed has a very low cost and a simple feasibility.
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Keywords
Yasin Özcelep and Ayten Kuntman
The purpose of this paper is to propose a time‐dependent mobility degradation model which is independent from the process or operating conditions.
Abstract
Purpose
The purpose of this paper is to propose a time‐dependent mobility degradation model which is independent from the process or operating conditions.
Design/methodology/approach
In total, four transistors under test are electrically stressed using constant positive electrical stress voltage technique with the gate bias of VG=40 V DC, where the source and drain were grounded. The authors increased the stress voltage step by step to avoid electrostatic discharge and recorded the ID‐VDS and ID‐VGS measurements in time intervals during the stress.
Findings
The experimental results show that the output current and the threshold voltage of the transistor are increased after the stress. Mobility and channel length are decreased. The changes in the transistor parameters were associated to interface state Si/SiO2 effects. The authors used the physical changes in transistor and proposed a new‐time dependent mobility degradation model. The mobility change was calculated using the proposed model and compared with the experimental results. It was seen that the calculated and experimental results are in good agreement.
Originality/value
This is an original research paper and enables the mobility degradation to be predicted independently from effects of process or operational changes such as oxide thickness, substrate doping, and applied voltages on transistor.
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Keywords
Abstract
Purpose
This work aims to investigate the modifications in a transistor behavior after hot carrier injection processes from the integrated junction.
Design/methodology/approach
A high voltage is applied across the drain‐source contacts, so a reverse current is induced through the integrated junction and defects are then created.
Findings
The results point out to a dependence of the VDMOSFET reliability on the operating conditions which could induce parasitic effects on the structure. Induced defects alter the form of several MOSFET characteristics.
Originality/value
A new method of degradation is presented along with a series of characterization techniques‐based electrical parameters variations.
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Ahmed Amir Tazibt and Farida Aoughlis
During crises such as accidents or disasters, an enormous volume of information is generated on the Web. Both people and decision-makers often need to identify relevant and timely…
Abstract
Purpose
During crises such as accidents or disasters, an enormous volume of information is generated on the Web. Both people and decision-makers often need to identify relevant and timely content that can help in understanding what happens and take right decisions, as soon it appears online. However, relevant content can be disseminated in document streams. The available information can also contain redundant content published by different sources. Therefore, the need of automatic construction of summaries that aggregate important, non-redundant and non-outdated pieces of information is becoming critical.
Design/methodology/approach
The aim of this paper is to present a new temporal summarization approach based on a popular topic model in the information retrieval field, the Latent Dirichlet Allocation. The approach consists of filtering documents over streams, extracting relevant parts of information and then using topic modeling to reveal their underlying aspects to extract the most relevant and novel pieces of information to be added to the summary.
Findings
The performance evaluation of the proposed temporal summarization approach based on Latent Dirichlet Allocation, performed on the TREC Temporal Summarization 2014 framework, clearly demonstrates its effectiveness to provide short and precise summaries of events.
Originality/value
Unlike most of the state of the art approaches, the proposed method determines the importance of the pieces of information to be added to the summaries solely relying on their representation in the topic space provided by Latent Dirichlet Allocation, without the use of any external source of evidence.
Details
Keywords
Duen-Ren Liu, Yun-Cheng Chou and Ciao-Ting Jian
Online news websites provide diverse article topics, such as fashion news, entertainment and movie information, to attract more users and create more benefits. Recommending movie…
Abstract
Purpose
Online news websites provide diverse article topics, such as fashion news, entertainment and movie information, to attract more users and create more benefits. Recommending movie information to users reading news online can enhance the impression of diverse information and may consequently improve benefits. Accordingly, providing online movie recommendations can improve users’ satisfactions with the website, and thus is an important trend for online news websites. This study aims to propose a novel online recommendation method for recommending movie information to users when they are browsing news articles.
Design/methodology/approach
Association rule mining is applied to users’ news and movie browsing to find latent associations between news and movies. A novel online recommendation approach is proposed based on latent Dirichlet allocation (LDA), enhanced collaborative topic modeling (ECTM) and the diversity of recommendations. The performance of proposed approach is evaluated via an online evaluation on a real news website.
Findings
The online evaluation results show that the click-through rate can be improved by the proposed hybrid method integrating recommendation diversity, LDA, ECTM and users’ online interests, which are adapted to the current browsing news. The experiment results also show that considering recommendation diversity can achieve better performance.
Originality/value
Existing studies had not investigated the problem of recommending movie information to users while they are reading news online. To address this problem, a novel hybrid recommendation method is proposed for dealing with cross-type recommendation tasks and the cold-start issue. Moreover, the proposed method is implemented and evaluated online in a real world news website, while such online evaluation is rarely conducted in related research. This work contributes to deriving user’s online preferences for cross-type recommendations by integrating recommendation diversity, LDA, ECTM and adaptive online interests. The research findings also contribute to increasing the commercial value of the online news websites.