The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Byunggook Park - One of the best experts on this subject based on the ideXlab platform.
-
trap profiling in Nitride storage Layer in 3 d nand flash memory using retention characteristics and ac text g _ mathrm m method
IEEE Electron Device Letters, 2015Co-Authors: Minkyu Jeong, Byunggook Park, Hojung Kang, Sungmin Joe, Sungkye Park, Jongho LeeAbstract:The trap density ( $N_{t}$ ) in Nitride storage Layer of 3-D NAND flash memory cells with tube-type channel structure is extracted. To extract $N_{t}$ profile in the Nitride Layer, retention characteristics, and ac-transconductance ( $\text{g}_{\rm m}$ ) method are used, and equations are derived in cylindrical coordinate. The $N_{t}$ profile at $E_{C}- E_{T}$ smaller than 1 eV is extracted using retention characteristics of the cells measured at high temperature. The peak value of extracted $N_{t}$ is $\sim 1 \times 10^{\mathbf {19}}$ cm $^{\mathbf {-3}}$ eV $^{\mathbf {-1}}$ at a $E_{C}-E_{T}$ of 0.93 eV. AC- $g_{\rm m}$ method is used to profile the $N_{t}$ in $ E_{C}-E_{T}$ higher than 1 eV. Extracted $N_{t}$ profile shows a reasonable continuity between both approaches and looks like a Gaussian function.
-
electron trap density distribution of si rich silicon Nitride extracted using the modified negative charge decay model of silicon oxide Nitride oxide silicon structure at elevated temperatures
Applied Physics Letters, 2006Co-Authors: I H Park, Hyungcheol Shin, Byunggook ParkAbstract:The authors modified the charge decay model of silicon-oxide-Nitride-oxide-silicon-type memory at the temperatures above 150°C. The modified model includes the effect of the internal electric field induced by the charges trapped in silicon Nitride Layer. The authors extracted the trap density distributions in energy level of the Si-rich silicon Nitride using the model and compared them with those of stoichiometric silicon Nitride. It has been revealed that the Si-rich silicon Nitride has larger trap density in shallow energy level than the stoichiometric silicon Nitride and this relation is reversed as the energy level goes deeper.
-
charge decay characteristics of silicon oxide Nitride oxide silicon structure at elevated temperatures and extraction of the Nitride trap density distribution
Applied Physics Letters, 2004Co-Authors: Hyungcheol Shin, Byunggook ParkAbstract:We investigated the charge decay characteristics of a silicon-oxide-Nitride-oxide-silicon type nonvolatile memory at elevated temperatures. Based on the amphoteric trap model and the thermal emission model of the trapped charge, we propose an advanced charge decay model which includes the effect of the bottom oxide, and apply it to extraction of the trap density distribution in energy levels of the Nitride Layer. The samples prepared have Nitride films deposited simultaneously and are classified into two groups according to the thickness of the bottom oxide. The trap density distributions extracted from two groups showed good consistency.
D Landolt - One of the best experts on this subject based on the ideXlab platform.
-
tribocorrosion behavior of plasma Nitrided ti 6al 4v alloy in neutral nacl solution
Surface & Coatings Technology, 2001Co-Authors: F P Galliano, Emanuele Galvanetto, S Mischler, D LandoltAbstract:Abstract The tribocorrosion behavior of plasma Nitrided Ti–6Al–4V alloy is investigated in a 0.9 M NaCl solution at room temperature by means of a sliding wear tribometer, utilizing alumina balls as the counterface material. Tests were performed at open circuit potential and under anodic polarization and the electrochemical parameters, namely anodic current, potential and galvanic current were continuously monitored. The plasma nitriding treatments were performed at two different temperatures, 973 K and 1173 K, and the resulting microstructures and phases were characterized. At 973 K a thin TiN–Ti 2 N Layer was formed while at the higher temperature this compound Layer was thicker and an inner hardened subLayer was present. In the absence of such an inner Layer the sliding of the alumina pins promoted the nucleation and growth of microcracks in the Nitride Layer, leading to quick failure of the coating. The samples treated at higher temperature showed a more uniform wear process of the Nitride Layer, without crack formation, and even after its removal, the hardened subLayer did not suffer from the typical delamination wear of untreated Ti–6Al–4V. The damaging or removal of the protective passive film due to rubbing leads to the formation of a galvanic couple between the anodic wear track and the outside surface. The fraction of electrochemically removed material with respect to the total wear volume was approximately 0.2 for the untreated alloy and 0.5 for the Nitride Layer.
M Ahsan - One of the best experts on this subject based on the ideXlab platform.
-
co2 laser gas assisted nitriding of ti 6al 4v alloy
Applied Surface Science, 2006Co-Authors: B S Yilbas, Cagdas Karatas, Omer Keles, I Y Usta, M AhsanAbstract:Abstract Laser gas assisted nitriding of Ti–6Al–4V alloy is carried out and Nitride compounds formed and their concentration in the surface vicinity are examined. SEM, XRD and XPS are accommodated to examine the Nitride Layer characteristics. Microhardness across the Nitride Layer is measured. Temperature field and nitrogen distribution due to laser irradiation pulse is predicted. It is found that the Nitride Layer appears like golden color; however, it becomes dark gold color once the laser power irradiation is increased. The δ-TiN and ɛ-TiN are dominant phases in the surface vicinity. The needle like dendrite structure replace with the feathery like structure in the surface region due to high nitrogen concentration. No porous or microcracks are observed in the Nitrided Layer, except at high power irradiation, in this case, elongated cracks are observed in the surface region where the nitrogen concentration is considerably high.
F T Cheng - One of the best experts on this subject based on the ideXlab platform.
-
laser diffusion nitriding of ti 6al 4v for improving hardness and wear resistance
Applied Surface Science, 2011Co-Authors: H C Man, M Bai, F T ChengAbstract:Abstract Owing to poor tribological properties, titanium (Ti) alloys are usually surface-treated to enhance their surface properties. Laser surface nitriding, among others, is a common method employed to increase hardness and wear resistance for Ti alloys. Conventional laser nitriding involves surface melting of Ti alloys in a nitrogen atmosphere. This inevitably results in a roughened surface and post-treatment might be required. The present study aims at laser diffusion nitriding Ti alloys without surface melting via carefully selecting the laser processing parameters. The Nitrided surface was characterized by X-ray diffractometry (XRD), optical microscopy (OM), scanning-electron microscopy (SEM), and profilometry. The Nitride Layer formed was about 1.62 μm upon repeated passes. The change in surface roughness resulting from laser diffusion nitriding was only minimal. Nanoindentation measurements revealed that the hardness of the Nitride Layer was around 11.3 GPa, being about 2.3 times that of Ti–6Al–4V. Ball-on-slab sliding wear test recorded a reduction in wear volume by about 8 times. The results of the present work thus demonstrate the feasibility of diffusion nitriding of Ti–6Al–4V by laser treatment for enhancing its surface properties and performance.
Hyungcheol Shin - One of the best experts on this subject based on the ideXlab platform.
-
electron trap density distribution of si rich silicon Nitride extracted using the modified negative charge decay model of silicon oxide Nitride oxide silicon structure at elevated temperatures
Applied Physics Letters, 2006Co-Authors: I H Park, Hyungcheol Shin, Byunggook ParkAbstract:The authors modified the charge decay model of silicon-oxide-Nitride-oxide-silicon-type memory at the temperatures above 150°C. The modified model includes the effect of the internal electric field induced by the charges trapped in silicon Nitride Layer. The authors extracted the trap density distributions in energy level of the Si-rich silicon Nitride using the model and compared them with those of stoichiometric silicon Nitride. It has been revealed that the Si-rich silicon Nitride has larger trap density in shallow energy level than the stoichiometric silicon Nitride and this relation is reversed as the energy level goes deeper.
-
charge decay characteristics of silicon oxide Nitride oxide silicon structure at elevated temperatures and extraction of the Nitride trap density distribution
Applied Physics Letters, 2004Co-Authors: Hyungcheol Shin, Byunggook ParkAbstract:We investigated the charge decay characteristics of a silicon-oxide-Nitride-oxide-silicon type nonvolatile memory at elevated temperatures. Based on the amphoteric trap model and the thermal emission model of the trapped charge, we propose an advanced charge decay model which includes the effect of the bottom oxide, and apply it to extraction of the trap density distribution in energy levels of the Nitride Layer. The samples prepared have Nitride films deposited simultaneously and are classified into two groups according to the thickness of the bottom oxide. The trap density distributions extracted from two groups showed good consistency.