Sangwoo Kang

Capacitorless Dynamic Random Access Memory Cell with Highly Scalable Surrounding Gate Structure

We propose the surrounding gate metal oxide semiconductor field effect transistor (MOSFET) with vertical channel [surrounding gate and vertical channel (SGVC) cell] as a one transistor (1T) dynamic random access memory (DRAM) cell. To confirm the memory operation of the SGVC cell, we fabricated a highly scalable SGVC cell. Because of its vertical channel structure and common source architecture, it can readily be made into a 4F2 cell array. The sensing margin was around 6 µA which is sufficiently large for read operation. Read retention time was about 4 ms meaning that the read operation is non-destructive. Also, we have revealed that not only an increase in the volume of the floating body region but also an adequate amount of charge is required for an increase in the sensing margin.

Capacitorless DRAM Cell with Highly Scalable Surrounding Gate Structure

To overcome the scalability issues and process complexity of 1-transistor/1-capacitor DRAM cell, capacitorless 1-transistor (1T) DRAM cells have been recently proposed and investigated [1]. The mainstream 1T DRAM cell is a floating body transistor cell (FBC) which consists of a MOSFET with its body floating electrically. The FBC is implemented by a MOSFET formed on partially depleted silicon-on-insulator (PD-SOI).[2,3] Because the floating body is used as a storage node, the FBC does not require complicated processes for storage capacitor. Therefore, the FBC has a simple process and can be made below 4F

Self-Aligned Dual-Gate Single-Electron Transistors

A novel complementary metal–oxide–semiconductor (CMOS) process compatible and self-aligned fabrication method for the dual-gate single-electron transistor (DG-SET) is presented. The performance of previous versions of the DG-SET was limited by inherent parasitic elements and its fabrication process was divergent from conventional CMOS, limiting the possibility of co-integration. Through simulation, the parasitic elements are confirmed to be caused by the non-self-alignment of the control gate, side gates, and source/drain. To resolve such issues, a new type of DG-SET was fabricated using a self-aligned process. Measurement results obtained at room temperature revealed clear Coulomb oscillation peaks in the trans-conductance curve. Through parameter extraction and its comparison with previous results, this is confirmed to be the consequence of single-electron tunneling. Also, in order to confirm that the single-electron tunneling is caused by the electrically induced tunneling barriers, and not by random fluctuations along the SOI active, low temperature measurement results for devices with different parameters is compared.

Improving the Endurance Characteristics Through Boron Implant at Active Edge in 1 G NAND Flash

One of the most important issues of NAND flash memory is reliability problems caused by oxide and interface traps. But it has been revealed that their generation rate increases by Fowler-Nordheim current stressing on the tunnel oxide as the channel width of shallow trench isolation (STI) isolated NAND flash cells shrinks and electric field is increased at active edge of STI profile. By adjusting the boron doping of active edge, we decrease not only the electric field but also the trap generation. Also we confirmed the improvement of endurance and bake retention characteristics.

Fabrication and Characteristics of Self-Aligned Dual-Gate Single-Electron Transistors

Single-electron transistors that have electrical tunneling barriers are fabricated, and Coulomb oscillation peaks and negative differential transconductance are observed at room temperature (300 K). Operation characteristics and multioscillation peaks are further investigated at low temperature (80 K). The period of Coulomb oscillation is 2.3 V due to an ultrasmall control gate capacitance, and oscillation peaks are shifted through the side gate bias, which is explained by the derived stability plot for dual-gate structures. Even with the side gates electrically floating, the device still operates as a single-electron transistor since the p-n junction barrier plays a role of tunneling barrier. In addition, by changing the bias condition, double dots are formed along the channel and peak splitting is observed.

Analytical modeling of field-induced interband tunneling-effect transistors and its application

In the room-temperature I-V characteristics of field-induced interband tunneling-effect transistors (FITETs), negative-differential conductance (NDC) characteristics as well as negative-differential transconductance (NDT) characteristics have been observed. The key operation principle of this quantum-tunneling device is the field-induced interband tunneling. To include the effect of interband tunneling, we have developed an analytical equation of interband tunneling current. Due to the inherent SOI-MOSFET structure of the FITET, the current equation of MOSFET has also been included in the analytical equation of the FITET. By comparing the calculated data from these two current components with the measured data, an additional excess tunneling current component has been introduced in the final analytical equation of the FITET. SPICE simulation results with this analytical model have shown good agreements with the experimental results. Also, this analytical model has been applied to verify the functionality of a simple digital logic gate such as XOR and four-level parity checker made by one FITET.

OP0059 Serum CXCL10 Levels Are Associated with Clinical Manifestations and Disease Activity in Behcet's Disease

Background Chemokines are multifunctional mediators that control leukocyte recruitment into the inflammatory sites and enhance immune responses. It remains to be investigated which chemokines are important in Behcets disease (BD). Objectives The objective of this study was to investigate serum levels of (C-X-C motif) CXC chemokines in BD patients and its association with clinical manifestations and disease activity. Methods Blood samples were collected from 109 BD patients and 34 age-, sex matched healthy controls (HCs). Twenty two follow-up samples were collected in BD patients. Serum CXC chemokines were assayed for the neutrophil chemoattractants (CXCL1 and CXCL8) and lymphocyte chemoattractants (CXCL9, CXCL10, CXCL12, CXCL13 and CXCL16) by using a multiplex assay. Cell surface makers such as CD3, CD4 and CXCR3 in peripheral blood mononuclear cells were investigated by flow cytometry. The clinical features including disease activity, laboratory tests and current medication were evaluated at the time of blood collection. C-X-C chemokine receptor 3 (CXCR3) expression in skin and intestinal lesions from BD patients were assessed via immunohistochemistry. Results Serum levels of CXCL8, CXCL10 and CXCL12 were significantly higher in the BD patients than in HC (p=0.001, p=0.007 and p=0.003, respectively). Serum CXCL10 levels were significantly correlated with disease activity in both Behcets Disease Current Activity Form (BDCAF) and Behcets Syndrome Activity Score (BSAS) (rho =0.336, p<0.001 and rho =0.253, p=0.009, respectively) as well as with number of genital ulcer and erythema nodosum (EN) (rho =0.222, p=0.020 and rho =0.329, p<0.001, respectively). In follow-up BD patients, changes of serum CXCL10 levels were correlated with those of BDCAF (rho =0.425, p=0.048). CXCR3 receptor expression was significantly increased on CD3 positive T cells versus CD3 negative cells in peripheral blood mononuclear cells of both BD patients and HCs (p=0.009 and p=0.031, respectively). Levels of serum CXCL10 were inversely correlated with percentage of CXCR3 expression on CD3 positive T cells in BD patients (rho = -0.523, p=0.022). In immunohistochemistry, the CXCR3 positive inflammatory cells were increased in skin lesions of BD patients than in those of HCs. Conclusions These results suggest that CXCL10/CXCR3 axis contribute to pathogenesis of BD particularly mucocutaneous lesions. Measurement of serum CXCL10 may help to assess disease activity in BD patients. Disclosure of Interest None declared

AB0053 CD20+CD27+CD43+CD70-Cells, Proposed as Human B-1 Cells Are Increased in Systemic Lupus Erythematosus, But Not Correlated with Disease Activity

Background Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of multiple autoantibodies by hyperactive B cells. B-1 cells distinguished from conventional B cell, perform a protective role in defending against microbial pathogens by secreting natural antibodies. Recently, human B-1 cells identified phenotypically according to the characterization of murine B-1 cells, were reported to be increased in peripheral blood of SLE patients. Objectives The aim of this study is to investigate the frequency of B-1 cells and its correlation with disease activity in SLE. Methods Peripheral blood mononuclear cells were isolated from 21 SLE patients and 16 age/sex matched healthy controls. Frequencies of B-1 cells were analyzed by multicolor flow cytometry using antibodies against CD3, CD20, CD27, CD43, and CD70. Phenotype of human B-1 cells was identified by CD3-CD20+CD27+CD43+CD70-. Correlation of B-1 cell frequency with the disease activity of SLE was analyzed according to anti-dsDNA antibody, complement level, renal involvement, platelets count, white blood cell count, erythrocyte sedimentation rate (ESR), and SLE disease activity index (SLEDAI) score. Results Absolute B cell count was significantly decreased in SLE patients compared to healthy controls (mean ± SE: 29813±8096 cells/ml vs. 62593±10465 cells/ml, p=0.002). Frequencies of B-1 cell in total B cells were significantly increased in SLE patients compared to healthy controls (1.86±0.33 vs. 0.79±0.10, p=0.025). SLE patients with anti-dsDNA antibody tended to have higher frequency of B-1 cells than patients without anti-dsDNA antibody (1.92±0.39 vs. 1.77±0.60). However there was no correlation between complement level, renal involvement, platelets count, white blood cell count, ESR, or SLEDAI score and B-1 cell frequency. Conclusions The frequencies of B-1 cell were significantly higher in SLE compared to healthy controls. But there was no correlation between disease activity and B-1 cell frequency. References Griffin DO, Holodick NE, and Rothstein TL. Human B1 cells in umbilical cord and adult peripheral blood express the novel phenotype CD20+ CD27+ CD43+ CD70-. J. Exp. Med 2011;208:67-80. Griffin DO, and Rothstein TL. Human B1 cell frequency: isolation and analysis of human B1 cells. Front. Immunol. 2012;3:122. Tørring C, Petersen CC, Bjerg L, et al. The B1-cell subpopulation is diminished in patients with relapsing-remitting multiple sclerosis. J Neuroimmunol. 2013;262:92-99. Disclosure of Interest None declared

AB0124 Inhibitory Effects of A Novel Bispecific Antibody against Tnf-Alpha and CXCL10 in Animal Model of Rheumatoid Arthritis

Background Tumor necrosis factor-α (TNF-α) plays a crucial role in the pathogenesis of rheumatoid arthritis (RA) and monoclonal antibodies targeting TNF-α are used as a popular therapeutic interventions in RA patients. CXCL10 is a chemokine that potentially plays a role in the immunopathogenesis of RA. The development of bispecific antibody (BiAb) as a therapeutic agent for RA may have great clinical potential. We constructed a single-chain BiAb against both TNF-α and CXCL10 (IgG-based format). Objectives We investigated the inhibitory effects of BiAb targeting TNF-α and CXCL10 on in vitro and in vivo model of RA. Methods We performed TNF-α neutralization assay using WEHI cell and tube formation assay of HUVEC cell to investigate TNF-α antagonistic effect of BiAb. Then we performed T cell migration assay induced by CXCL10 using transwell system and inhibitory assay of osteoclastogenesis. The effects of BiAb were determined by arthritis severity score, histological damage in Tg197 human TNF transgenic mice. Results BiAb suppressed TNF-α comparatively with adalimumab in TNF-α neutralization assay, tube formation assay and osteoclast differentiation. Cell migration induced by CXCL10 was inhibited by BiAb dose dependently. Treatment with BiAb resulted in beneficial effects on clinical and histological parameters of Tg197 human TNF transgenic mice model. Conclusions Our results demonstrate the novel BiAb effectively neutralized TNF-α and CXCL10 in vitro and in vivo model of rheumatoid arthritis. We suggest that BiAb could be a promising biologic agent for the treatment of RA. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.3074

Fabrication and improved characteristics of self-aligned dual-gate single-electron transistors

Single-electron transistors (SETs) have been expected to become one of the promising devices in future ultra-low power and high-density systems. Especially, silicon based SETs have advantages in the fabrication and design of SET and MOSFET hybrid circuits. Due to its potential, lots of research has been conducted and various structures have been introduced. However, low operation temperature and poor fabrication controllability still remain as main obstacles to widespread utilization. In this respect, dualgate SETs using electrical tunneling barriers have strengths compared to other structures. This is because the height of the tunneling barriers can be controlled through external bias and the quantum dot size is further decreased due to electric field effects. In our research, dual-gate SETs were fabricated with a CMOS compatible and self-aligned process. Process parameters were optimized in order to reduce the total capacitance of a quantum dot, and Coulomb oscillation peak was observed in the roomtemperature operation of the fabricated device.