Mitigating Pillar-to-Pillar Variability of Ground Select Transistor in 3-D NAND Flash Memory
IEEE TRANSACTIONS ON ELECTRON DEVICES
Authors: Bhatt, Upendra Mohan; Manhas, Sanjeev Kumar; Nayyar, Kaustubh; Kumar, Arvind; Pakala, Mahendra
Abstract
The threshold voltage variability of the select transistors is an important issue in the development of 3-D NAND flash memory. Particularly, pillar-to-pillar variations in threshold voltage (V-T) of the ground select transistor (GST) are critical across the wafer. The V-T variation is attributed to the nonuniformity in the plug height of the epitaxially grown silicon layers in different pillars. In this article, we propose different techniques to achieve performance uniformity in different strings across the wafer in terms of V-T distribution of GST. We show that by optimizing the channel doping and gate metal work function (WF) of the GST, the NAND string V-T nonuniformity can be eliminated. It is also shown that V-T variability can be further minimized by optimizing GST gate length. Further, we present a two-MOSFET model for the pillar-to-pillar V-T variation across the wafer. This study provides important results for designing 3-D NAND memories with higher performance uniformity for the pillar-to-pillar variations in strings across the wafer.
Identification of phostensin in association with Eps 15 homology domain-containing protein 1 (EHD1) and EHD4
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Authors: Lin, Yu-Shan; Huang, Kuang-Yung; Yu, Hui-Chun; Lu, Ming-Chi; Fan, Cheng-Jhong; Tseng, Hsien-Yu Huang; Jhuang, Bi-Yao; Liu, Su-Qin; Lai, Ning-Sheng; Lin, Ta-Hsien; Huang, Hsien-Bin
Abstract
Phostensin (PTS) encoded by KIAA1949 is a protein phosphatase 1 (PP1)-binding protein. In order to explore the cellular functions of PTS, we have searched PTS-binding proteins by using coimmunoprecipitation in combination with shotgun proteomics. Here, we report two novel PTSbinding proteins, Eps 15 homology domain-containing protein 1 (EHD1) and EHD4. PTS associated with EHD proteins was also observed in GST pull-down assays. Immunofluorescence microscopy demonstrated that the complex was co-localized at the endocytic vesicles. EHD proteins have been known to play a critical role in regulation of endocytic transport. Overexpression of PTS-beta can attenuate the endocytic trafficking of transferrin. (C) 2020 Elsevier Inc. All rights reserved.