• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.3
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• pp.111-115
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• 2006

We investigated accelerated soft error rate(ASER) in 8M static random access memory(SRAM) cells. The effects on ASER by well structure, operational voltage, and cell transistor threshold voltage are examined. The ASER decreased exponentially with respect to operational voltage. The chips with buried nwell1 layer showed lower ASER than those either with normal well structure or with buried nwell1 + buried pwell structure. The ASER decreased as the ion implantation energy onto buried nwell1 changed from 1.5 MeV to 1.0 MeV. The lower viscosity of the capping layer also revealed lower ASER value. The decrease in the threshold voltage of driver or load transistor in SRAM cells caused the increase in the transistor on-current, resulting in lower ASER value. We confirmed that in order to obtain low ASER SRAM cells, it is necessary to also the buried nwell1 structure scheme and to fabricate the cell transistors with low threshold voltage and high on-current.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.4
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• pp.199-203
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• 2006

This paper presents an ASER (Accelerated Soft Error Rate) integral model. The model is based on the facts that the generated EHP/s(electron hole pairs) are diminished after some residual range of the incident alpha particle, where residual range is a function of the incident angle and the capping layer thickness over the semiconductor junction. The ASER is influenced by the flux of the alpha particles, the junction area ratio, the alpha particle incident angle when the critical charge is same as the collected charge, and the sizes of the alpha source and the chip. The model was examined with 8M static RAM samples. The measured ASER data showed good agreement with the calculated values using the model. The ASER decreased exponentially with respect to the operational voltage. As the capping layer thickness increases up to $16{\mu}m$, the ASER increases, and after that thickness, the ASER decreases. The ASER increased as the depth of BNW increased from $0{\mu}m\;to\;4{\mu}m$. and then saturated. The ASER decreased as the node capacitance increased from 2fF to 5fF.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.6
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• pp.242-245
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• 2005

We compared and analyzed ASER (Accelerated Soft Error Rate) for cell structures and metal plate capacitance in the fabricated 16M SRAM. Application of the BNW (Buried NWELL) lowered the ASER value compared to the normal well structure. By applying the metal plate capacitor with the BNW, the lowest ASER value can be obtained. The thinner oxide thickness of the metal plate capacitor provides higher capacitance and lower ASER value. The ASER is improved from 2200 FIT to 1000 FIT after sole application of the BNW. However, it is dramatically improved to 15 FIT once the metal plate capacitor is additionally applied.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.6
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• pp.507-511
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• 2006

We investigated accelerated soft error rate (ASER) in static random access memory (SRAM) cells of thin film transistor (TFT) type. The effects on ASER by cell density, buried nwell structure, operational voltage, and polysilicon-2 layer thickness were examined. The increase in the operational voltage, and the decrease in the density of SRAM cells, respectively, resulted in the decrease of ASER values. The SRAM chips with buried nwell showed lower ASER than those with normal well structure did. The ASER decreased as the test distance from alpha source to the sample increased from $7{\mu}m\;to\;15{\mu}m$. As the polysilicon-2 thickness increased up to $1000\;{\AA}$, the ASER decreased exponentially. In conclusion, the best condition for low soft error rate, which is essential to obtain highly reliable SRAM device, is to apply the buried nwell structure scheme and to fabricate thin film transistors with the thick polysilicon-2 layer

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.1
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• pp.15-18
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• 2003

The characteristics of accelerated soft error rate (ASER) for fabricated 8M SRAM are evaluated for various well structures. The application of the Buried NWell (BNW) and the variations of each well structure, well dose in process conditions are checked by ASER failure in time (FIT) in terms of reliability. The application of only the BNW shows the lowest ASER FIT value. The BNW added to the Buried PWell (BPW) shows a 200% increase and the BNW plus the Striped BPW (SBPW) shows a 100% increase compared to applying the BNW. The cases of applying SBPW show very high ASER FIT.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.4
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• pp.1-8
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• 2012

This paper presents a method for obtaining an exact average symbol error rate (ASER) of M-ary Phase Shift Keying (MPSK) for opportunistic amplify-and-forward (OAF) relay systems over Rayleigh fading channels. This is based on the relay selection probability when a relay is selected as the best one with respect to the received signal-to-noise ratio. We then derive the modified moment generating function (MGF) for OAF relay systems by taking the given relay selection probability into consideration. Based on the modified MGF, we derive the exact ASER which accurately explicates OAF relay system characteristics. Our results confirm that the derived ASER provides a tight upper bound for OAF relay systems.

• Journal of Korean Society for Quality Management
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• v.32 no.3
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• pp.10-28
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• 2004

This research analysed the Interaction which focus on service quality perception, customer satisfaction, re-use intention in the golf club. First of all, we review the existing literature on measurement of service quality and management. As a result of this review and survey of the employer in golf club, thirteen factors emerged as important to the service management of the golf club; Reservation and Access(RSNA), Golf Course and Convenience Facilities(GCNF), Personal Services(PSER) and After Services(ASER). The structural equation model was utilized for analyzing the influence of service quality factors upon the customer satisfaction and re-use intention. Results show that service quality factors have a statistically significant impact on the customer satisfaction of the golf club. RSNA and GCNF investigated the factors influencing on the satisfaction degree of the customers. But the GCNF and PSER were not significant. Especially, GCNF factors directly influenced on the customer satisfaction and also indirectly impact on the intention of using again.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.686-689
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• 2004

As the demands of X-Y linear motors increase, it becomes very important to measure flatness errors and to compensate them. In this study, in order to investigate flatness errors, a laser interferometer is used for measurement. To improve the measurement efficiency, a Union Jack method is adopted instead of a square method. The square method is frequently used because of its accuracy, but it requires many measurement points. In this study, the Union Jack method with Grey Theory is used. By using the Grey Theory, unmeasured data are predicted, and these are compared with results of the square method. The results show that the Union Jack method with Grey Theory is accurate enough to replace the square method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.2
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• pp.548-558
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• 1995

An experimental investigation has been conducted to study the spray and combustion characteristics using the air-assisted twin fluid atomizer. Axial mean and fluctuating velocity components as well as drop-size distributions in non-reaction spray were measured with a nonintrusive phase doppler technique. Droplet number density distributions were also visualized using high speed CCD camera. Locations of spray and flame boundaries are obtained by direct photographic method. It is confirmed that at the fixed fuel flow rate, the increase of the atomizing air flow causes improvements on both spray and combustion characteristics under stable flame conditions. Internal group combustion modes where flame is located inside the spray boundary are observed to exist in the upstream region of higher droplet number density.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.816-819
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• 2000

Recently the styrofoam has been used fur material of press die pattern. The object of this research is to develope an automated laser system for manufacture of press die pattern which depends chiefly on handwork during its process. After converting 3-D CAD model into cross-sectional shape information, the unnecessary part of the section is vapored away by laser. The depth and width of cut are mainly under the control of laser power and beam feed rate. The optimum manufacturing conditions are obtained by preliminary experiments. It is necessary fur precise styrofoam pattern manufacturing to develope laser system which has sufficient motion accuracy and program or beam path generation and automatic control of this system.