• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.751-754
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• 2000

When charge-trap SONOS cells are used flash memory, the tunneling program/erase condition to minimize the generation of interface traps was investigated. SONOSFET NVSM cells were fabricated using 0.35$\mu\textrm{m}$ standard memory cell embedded logic process including the ONO cell process. based on retrograde twin-well, single-poly, single metal CMOS process. The thickness of ONO triple-dielectric for memory cell is tunnel oxide of 24${\AA}$, nitride of 74 ${\AA}$, blocking oxide of 25 ${\AA}$, respectively. The program mode(Vg: 7,8,9 V, Vs/Vd: -3 V, Vb: floating) and the erase mode(Vg: -4,-5,-6 V, Vs/Vd: floating, Vb: 3V) by modified Fowler-Nordheim(MFN) tunneling were used. The proposed programming condition for the flash memory of SONOSFET NVSM cells showed less degradation($\Delta$Vth, S, Gm) characteristics than channel MFN tunneling operation. Also the program inhibit conditions of unselected cell for separated source lines NOR-tyupe flash memory application were investigated. we demonstrated that the program disturb phenomenon did not occur at source/drain voltage of 1 V∼4 V and gate voltage of 0 V∼4.

• Journal of the Semiconductor & Display Technology
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• v.16 no.2
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• pp.66-69
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• 2017

In this paper, solution based Indium Zinc Oxide thin film transistors (IZO TFTs) were fabricated with PVP gate dielectric. To enhance the electrical properties, UV-O3 treatment is proposed on solution based IZO TFTs. The gate leakage current and interface trap density is compatible with conventional ZnO-based TFT with inorganic gate insulator. Especially, the UV-treated device shows improved electrical characteristics compared to the untreated device. These results can be explained by X-ray photoelectron spectroscopy (XPS) analysis, which shows that the oxygen vacancy of UV-O3 treatment is higher than that of no treatment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.1
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• pp.43-47
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• 2024

The size of semiconductor devices has been scaled down to improve packing density and output performance. However, there is uncontrollable spreading of the dopants that comprise the well, punch-stop, and channel-stop when using high-temperature annealing processes, such as rapid thermal annealing (RTA). In this context, low-temperature deuterium annealing (LTDA) performed at a low temperature of 300℃ is proposed to reduce the thermal budget during CMOS fabrication. The LTDA effectively eliminates the interface trap in the gate dielectric layer, thereby improving the electrical characteristics of devices, such as threshold voltage (V_TH), subthreshold swing (SS), on-state current (I_ON), and off-state current (I_OFF). Moreover, the LTDA is perfectly compatible with CMOS processes.

• Journal of the Korean Vacuum Society
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• v.14 no.2
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• pp.91-96
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• 2005

The silicon-on-insulator (SOI) wafer fabrication technique has been developed by using ion-cut process, based on proton implantation and wafer bonding techniques. It has been shown by SRIM simulation that 65keV proton implantation is required for a SOI wafer (200nm SOI, 400nm BOX) fabrication. In order to investigate the optimum proton dose and primary annealing condition for wafer splitting, the surface morphologic change has been observed such as blistering and flaking. As a result, effective dose is found to be in the $6\~9\times10^{16}\;H^+/cm^2$ range, and the annealing at $550^{\circ}C$ for 30 minutes is expected to be optimum for wafer splitting. Direct wafer bonding is performed by joining two wafers together after creating hydrophilic surfaces by a modified RCA cleaning, and IR inspection is followed to ensure a void free bonding. The wafer splitting was accomplished by annealing at the predetermined optimum condition, and high temperature annealing was then performed at $1,100^{\circ}C$ for 60 minutes to stabilize the bonding interface. TEM observation revealed no detectable defect at the SOI structure, and the interface trap charge density at the upper interface of the BOX was measured to be low enough to keep 'thermal' quality.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.116-124
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• 2008

Statement of the problem: Implant systems result in gaps and cavities between implant and abutment that can act as a trap for bacteria and thus possibly cause inflammatory reactions in the peri-implant soft tissues. Purpose: Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Treponema denticola, and Aggregatibacter actinomycetemcomitans, related to implant-abutment interface microleakage. Material and methods: Samples were taken from 27 subjects with sterilized paper points and were transported in $1{\times}PBS$. The detection of periodontopathogens were performed by polymerase chain reaction with species-specific primers based on 16S rDNA. Results: Our data showed that the detection rate of P. gingivalis and P. intermedia in implant fixture was 59% and 82% in patients respectively. Detection rate of P. gingivalis and P. intermedia in implant crevice was 44% and 82% in patients. Detection rate of P. gingivalis and P. intermedias in tongue was 82% and 82% in patients. Conclusion: Current implant systems cannot safely prevent microbial leakage and bacterial colonization of the inner part of the implant.

• Korean Journal of Materials Research
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• v.4 no.1
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• pp.63-74
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• 1994

The ultrathin oxide films less than 100$\AA$ were grown by thermal oxidation in $N_2O$ ambient to improve the controllability of thickness, thickness uniformity, process reproducibility and their electrical properties. Oxidation rate was reduced significantly at very thin region due to the formation of oxynitride layer in $N_2O$ ambient and moreover nitridation of the oxide layer was simultaneously accompanied during growth. The nitrogen incorporation in the grown oxide layer was characterized with the wet chemical etch-rate and ESCA analysis of the grown oxide layer. All the oxides thin films grown in $N_2O$, pure and dilute $O_2$ ambients show Fowler-Nordheim electrical conduction. The electrical characteristics of thin oxide films grown in $N_2O$ such as leakage current, electrical breakdown, interface trap density generation due to the injected electron and reliability were better than those in pure or dilute ambient. These improved properties can be explained by the fact that the weak Si-0 bond is reduced by stress relaxation during oxidation and replacement by strong Si-N bond, and thus the trap sites are reduced.

• The Korean Journal of Ceramics
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• v.6 no.2
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• pp.138-142
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• 2000

Thin film $LiNbO_3$MFS (metal-ferroelectric-semiconductor) capacitor showed improved characteristics such as low interface trap density, low interaction with Si substrate, and large remanent polarization. This paper reports ferroelectric $LiNbO_3$thin films grown directly on p-type Si (100) substrates by 13.56 MHz RF magnetron sputtering system for FRAM (ferroelectric random access memory) applications. RTA (rapid thermal anneal) treatment was performed for as-deposited films in an oxygen atmosphere at $600^{\circ}C$ for 60sec. We learned from X-ray diffraction that the RTA treated films were changed from amorphous to poly-crystalline $LiNbO_3$which exhibited (012), (015), (022), and (023) plane. Low temperature film growth and post RTA treatments improved the leakage current of $LiNbO_3$films while keeping other properties almost as same as high substrate temperature grown samples. The leakage current density of $LiNbO_3$films decreased from $10^{-5}$ to $10^{-7}$A/$\textrm{cm}^2$ after RTA treatment. Breakdown electric field of the films exhibited higher than 500 kV/cm. C-V curves showed the clockwise hysteresis which represents ferroelectric switching characteristics. Calculated dielectric constant of thin film $LiNbO_3$illustrated as high as 27.9. From ferroelectric measurement, the remanent polarization and coercive field were achieved as 1.37 $\muC/\textrm{cm}^2$ and 170 kV/cm, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.331-331
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• 2009

Hafnium oxide ($HfO_2$) attracted by one of the potential candidates for the replacement of si-based oxides. For applications of the high-k gate dielectric material, high thermodynamic stability and low interface-trap density are required. Furthermore, the amorphous film structure would be more effective to reduce the leakage current. To search the gate oxide materials, metal-insulator-metal (MIM) capacitors was fabricated by pulsed laser deposition (PLD) on indium tin oxide (ITO) coated glass with different oxygen pressures (30 and 50 mTorr) at room temperature, and they were deposited by Au/Ti metal as the top electrode patterned by conventional photolithography with an area of $3.14\times10^{-4}\;cm^2$. The results of XRD patterns indicate that all films have amorphous phase. Field emission scanning electron microscopy (FE-SEM) images show that the thickness of the $HfO_2$ films is typical 50 nm, and the grain size of the $HfO_2$ films increases as the oxygen pressure increases. The capacitance and leakage current of films were measured by a Agilent 4284A LCR meter and Keithley 4200 semiconductor parameter analyzer, respectively. Capacitance-voltage characteristics show that the capacitance at 1 MHz are 150 and 58 nF, and leakage current density of films indicate $7.8\times10^{-4}$ and $1.6\times10^{-3}\;A/cm^2$ grown at 30 and 50 mTorr, respectively. The optical properties of the $HfO_2$ films were demonstrated by UV-VIS spectrophotometer (Scinco, S-3100) having the wavelength from 190 to 900 nm. Because films show high transmittance (around 85 %), they are suitable as transparent devices.

• Mass Spectrometry Letters
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• v.3 no.1
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• pp.10-14
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• 2012

Artificially oxidized cysteine residues in peroxiredoxin 6 (Prx6) were detected by electrospray interface capillary liquid chromatography-linear ion trap mass spectrometry after the preparation of two-dimensional gel electrophoresis (2D-GE). We used Prx6 as a model protein because it possesses only two cysteine residues at the 47th and 91st positions. The spot of Prx6 on 2D-GE undergoes a basic (isoelectric point, pI 6.6) to acidic (pI 6.2) shift by exposure to peroxide due to selective overoxidation of the active-site cysteine Cys-47 but not of Cys-91. However, we detected a tryptic peptide containing cysteine sulfonic acid at the 47th position from the basic spot and a peptide containing both oxidized Cys-47 and oxidized Cys-91 from the acidic spot of Prx6 after the separation by 2D-GE. We prepared two types of oxidized Prx6s: carrying oxidized Cys-47 (single oxidized Prx6), and other carrying both oxidized Cys-47 and Cys-91 (double oxidized Prx6). Using these oxidized Prx6s, the single oxidized Prx6 and double oxidized Prx6 migrated to pIs at 6.2 and 5.9, respectively. These results suggest that oxidized Cys-47 from the basic spot and oxidized Cys-91 from the acidic spot are generated by artificial oxidation during sample handling processes after isoelectric focusing of 2D-GE. Therefore, it is important to make sure of the origin of cysteine oxidation, if it is physiological or artificial, when an oxidized cysteine residue(s) is identified.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.11
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• pp.941-948
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• 2009

The present study aims at the examination of the effects of 1 mol% NiO addition on the reaction, microstructure development, resultant electrical properties, and especially the bulk trap and interface state levels of $ZnO-Bi_2O_3-Sb_2O_3$ (Sb/Bi=0.5, 1.0, and 2.0) systems (ZBS). The samples were prepared by conventional ceramic process, and characterized by density, XRD, SEM, I-V, impedance and modulus spectroscopy (IS & MS) measurement. The sintering and electrical properties of Ni-doped ZBS (ZBSN) systems were controlled by Sb/Bi ratio. Pyrochlore ($Zn_2Bi_3Sb_3O_{14}$) was decomposed more than $100^{\circ}C$ lowered in ZBS (Sb/Bi=1.0) by Ni doping. The reproduction of pyrochlore was suppressed by the addition of Ni in ZBS. Between two polymorphs of $Zn_7Sb_2O_{12}$ spinel ($\alpha$ and $\beta$), microstructure of ZBSN (Sb/Bi=0.5) composed of a-spinel was more homogeneous than $Sb/Bi{\geq}1.0$ composed of $\beta$-spinel phase. In ZBSN, the varistor characteristics were not improved drastically (non-linear coefficient $\alpha\;=\;6{\sim}11$) and independent on microstructure according to Sb/Bi ratio. Doping of Ni to ZBS seemed to form ${V_0}^{\cdot}$ (0.33 eV) as dominant bulk defect. From IS & MS, especially the grain boundaries of Sb/Bi=0.5 systems were divided into two types, i.e. sensitive to oxygen and thus electrically active one and electrically inactive intergranular one with temperature.