• Korean Journal of Materials Research
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• v.11 no.3
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• pp.159-163
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• 2001

The success of SDB (silicon wafer direct bonding) technology can be estabilished by bonding on the bonded interface with no defects and Preventing temperature dependent bubbles. In this research, we observed the behavior of the intrinsic bubbles by transmitting the infrared light and the increase of the bubble pressure was found. And, the $SiO_2$-$SiO_2$ bonded wafer was achieved, which generates no intrinsic bubbles in the annealing under the atmospheric pressure. The intrinsic bubbles in the $SiO_2$-$SiO_2$ bonded wafer were generated in the annealing in the ultra high vacuum. This experimental result shows the relation between the bubble growth and the pressure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.796-803
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• 1998

Intrinsic and proximity gettering are popular processes to get higher cumulative production yield and usually adopt multi-step annealing and high energy ion implantation, respectively. In order to test the combined processed of these, high energy \ulcornerAs\ulcorner ion implantation and 2-step annealing process were adopted. After the ion implantation followed by 2-step annealing, the wafers were cleaved and etched with Wright etchant. The morphology of cross section on samples was inspected by FESEM. The concentration profile of As was measured by SRP. The location and type of secondary defects inspected by HRTEM were dependent on the 1st annealing temperatures. That is, a line of dislocation located at $1.5mutextrm{m}$ apart from the surface at $600^{\circ}C$ lst annealing was changed to some dislocation lines or loops nearby the surface at 100$0^{\circ}C$. The density of dislocation line was reduced but the size of the defects was enlarged as the temperature increased.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.128-133
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• 1999

In recent years, LSI devices have become more powerful and lower-priced, caused by a development of various wafer materials and an increase in the diameter of wafers. On the other hand, these have created some serious problems in manufacturing of wafers because materials used as semiconductor substrate are very brittle. In view of this fact, there are some trials to apply shear-mode(or ductile-mode) grinding for efficient manufacturing of semiconductor wafers instead of conventional lapping process. In fact grinding process that has not only more excellent degree of accuracy but also more adaptable to fully automated manufacturing than lapping, is already used in Si machining field. This paper described the elementary studies to establish the grinding technology of wafers. First, we investigated the variation of grinding force and the transition of grinding mode as various grinding conditions. Then, it was inspected that the change of grinding force affected the integrity such as the topography and the roughness of ground surfaces, and led to the chemical defects generation and distribution in damaged layer. The degree of defects was estimated by FT-IR(Fourier Transformed Infrared) Spectroscopy and Auger Electron Spectroscopy

• Journal of Radiation Protection and Research
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• v.48 no.3
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• pp.124-130
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• 2023

Background: When bipolar junction transistors (BJTs) are used as switches, their switching characteristics can be deteriorated because the recombination time of the minority carriers is long during turn-off transient. When BJTs operate as low frequency switches, the power dissipation in the on-state is large. However, when BJTs operate as high frequency switches, the power dissipation during switching transients increases rapidly. Materials and Methods: When silicon (Si) BJTs are irradiated by fast neutrons, defects occur in the Si bulk, shortening the lifetime of the minority carriers. Fast neutron irradiation mainly creates displacement damage in the Si bulk rather than a total ionization dose effect. Defects caused by fast neutron irradiation shorten the lifetime of minority carriers of BJTs. Furthermore, these defects change the switching characteristics of BJTs. Results and Discussion: In this study, experimental results on the switching characteristics of a pnp Si BJT before and after fast neutron irradiation are presented. The results show that the switching characteristics are improved by fast neutron irradiation, but power dissipation in the on-state is large when the fast neutrons are irradiated excessively. Conclusion: The switching characteristics of a pnp Si BJT were improved by fast neutron irradiation.

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.637-641
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• 2012

Due to its high production cost and relatively high energy consumption during the Siemens process, poly-silicon makers have been continuously and eagerly sought another silicon route for decades. One candidate that consumes less energy and has a simpler acidic and metallurgical purification procedure is upgraded metallurgical-grade (UMG) silicon. Owing to its low purity, UMG silicon often requires special steps to minimize the impurity effects and to remove or segregate the metal atoms in the bulk and to remove interfacial defects such as precipitates and grain boundaries. A process often called the 'gettering process' is used with phosphorus diffusion in this experiment in an effort to improve the performance of silicon solar cells using UMG silicon. The phosphorous gettering processes were optimized and compared to the standard POCl process so as to increase the minority carrier lifetime(MCLT) with the duration time and temperature as variables. In order to analyze the metal impurity concentration and distribution, secondary ion mass spectroscopy (SIMS) was utilized before and after the phosphorous gettering process.

• Journal of the Semiconductor & Display Technology
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• v.17 no.4
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• pp.1-5
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• 2018

Atomic force microscopy (AFM) simulation for Si (001) surface defects was conducted by using density functional theory (DFT). Three major defects on the Si (001) surface are difficult to analyze due to external noises that are always present in the images obtained by AFM. Noise-free surface defects obtained by simulation can help identify the real surface defects on AFM images. The surface defects were first optimized by using a DFT code. The AFM tip was designed by using five carbon atoms and positioned on the surface to calculate the system's energy. Forces between tip and surface were calculated from the energy data and converted into an AFM image. The simulated AFM images are noise-free and, therefore, can help evaluate the real surface defects present on the measured AFM images.

• Proceedings of the Materials Research Society of Korea Conference
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• 1995.11a
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• pp.25-26
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• 1995

• Imaging Science in Dentistry
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• v.45 no.1
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• pp.23-29
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• 2015

Purpose: This study aimed to assess the reliability of measurements performed on three-dimensional (3D) virtual models of maxillary defects obtained using cone-beam computed tomography (CBCT) and 3D optical scanning. Materials and Methods: Mechanical cavities simulating maxillary defects were prepared on the hard palate of nine cadavers. Images were obtained using a CBCT unit at three different fields-of-views (FOVs) and voxel sizes: 1) $60{\times}60mm$ FOV, $0.125mm^3$ ($FOV_{60}$); 2) $80{\times}80mm$ FOV, $0.160mm^3$ ($FOV_{80}$); and 3) $100{\times}100mm$ FOV, $0.250mm^3$ ($FOV_{100}$). Superimposition of the images was performed using software called VRMesh Design. Automated volume measurements were conducted, and differences between surfaces were demonstrated. Silicon impressions obtained from the defects were also scanned with a 3D optical scanner. Virtual models obtained using VRMesh Design were compared with impressions obtained by scanning silicon models. Gold standard volumes of the impression models were then compared with CBCT and 3D scanner measurements. Further, the general linear model was used, and the significance was set to p=0.05. Results: A comparison of the results obtained by the observers and methods revealed the p values to be smaller than 0.05, suggesting that the measurement variations were caused by both methods and observers along with the different cadaver specimens used. Further, the 3D scanner measurements were closer to the gold standard measurements when compared to the CBCT measurements. Conclusion: In the assessment of artificially created maxillary defects, the 3D scanner measurements were more accurate than the CBCT measurements.

• Journal of the Korean Vacuum Society
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• v.9 no.3
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• pp.216-220
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• 2000

Photoluminescence (PL) results of $Si^+$-implanted $SiO_2$films on crystalline silicon are reported. Visible and infrared PL are observed for all the samples. The PL spectrums have about 7000 $\AA$, 7400 $\AA$ and 8400 $\AA$ peak positions. As amount of $Si^+$ ion dose changed, the PL peak positions and intensity are changed. In particular, the PL spectrum has three peaks and more intensity than the other $Si^+$ ion implantation samples for $1{\times}10^{17}/cm^2$ $Si^+$ ion implantation. Not nanocrystal but defects that $Si^+$ ions treated are contributed to the PL spectrum. For the changes of $Si^+$ ion dose and annealing time, O rich radiative defects, Si rich radiative defects, and nonradiative defects control the PL spectrum. We confirmed that more radiative defects can be created by control of $Si^+$ ion dose.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.4
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• pp.336-346
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• 1994

We studied the reaction between silicon and carbon. Silicon granules and silicon with 0.2 wt% carbon powders were prepared for sample and then they were heated up to the $1450^{\circ}C, 1550^{\circ}C, 1650^{\circ}C, 1700^{\circ}C$ and were dwelled 1 hr and 4 hrs, respectively. we studied the change of morphologies of molten silicon and the formation of SiC following the reaction withcarbon using optical microscope, SEM, and XRD. Above the melting point of silicon, oxygens are precipitated during the decomposition of quartz used crucible. SiO formed from the reaction between molten silicon and precipitated oxygen evaporated and made the surface defects. SiC were formed with the reaction between the unreacted carbon and molten silicon. Polytype of the SiC formed at the solidification interface was ${\alpha}-SiC$.