2D-TCAD Simulation on Retention Time of Z2FET for DRAM Application

Duan, M. , Adamu-Lema, F., Cheng, B., Navarro, C., Wang, X., Georgiev, V.P. , Gamiz, F., Millar, C. and Asenov, A. (2017) 2D-TCAD Simulation on Retention Time of Z2FET for DRAM Application. In: SISPAD 2017: International Conference on Simulation of Semiconductor Processes and Devices, Kamakura, Japan, 7-9 Sept 2017, pp. 325-328. (doi: 10.23919/SISPAD.2017.8085330)

149426.pdf - Accepted Version



Traditional memory devices are facing more challenges due to continuous down-scaling. 6T-SRAM suffers from variability [1-2] and reliability [3-4] issues, which introduce cell stability problems. DRAM cells with one transistor, one capacitor (1T1C) struggle to maintain refresh time [5-6]. Efforts have been made to find new memory solutions, such as one transistor (1T) solutions [7-9]. Floating body based memory structures are among the potential candidates, but impact ionization or band-to-band tunnelling (B2BT) limits their refresh time [10]. A recently proposed zero impact ionization and zero subthreshold swing device named Z2FET [9, 11-12] has been demonstrated and is a promising candidate for 1T DRAM memory cell due to technology advantages such as CMOS technology compatibility, novel capacitor-less structure and sharp switching characteristics. In the Z2FET memory operation, refresh frequency is determined by data retention time. Previous research [11-12] is lacking systematic simulation analysis and understanding on the underlying mechanisms. In this paper, we propose a new simulation methodology to accurately extract retention time in Z2FET devices and understand its dependency on applied biases, temperatures and relevant physical mechanisms. Since the stored ‘1’ state in Z2FET is an equilibrium state [9, 11-12] and there is no need to refresh, we will concentrate on state ‘0’ retention. Two types of ‘0’ retention time: HOLD ‘0’ and READ ‘0’ retention time will be discussed separately.

Item Type:Conference Proceedings
Glasgow Author(s) Enlighten ID:Wang, Dr Xingsheng and Asenov, Professor Asen and Duan, Dr Meng and Cheng, Dr Binjie and Georgiev, Professor Vihar and Adamu-Lema, Dr Fikru
Authors: Duan, M., Adamu-Lema, F., Cheng, B., Navarro, C., Wang, X., Georgiev, V.P., Gamiz, F., Millar, C., and Asenov, A.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Copyright Holders:Copyright © 2017 The Japan Society of Applied Physics
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
702351REMINDERAsen AsenovEuropean Commission (EC)687931ENG - ENGINEERING ELECTRONICS & NANO ENG