| MS Seminar

Name of the Speaker: Mr. Arvind Kumar Singh (EE21S119)
Guide: Prof. Anbarasu Manivannan
Online meeting link: https://meet.google.com/oin-mgps-hxp
Date/Time: 14th March 2025 (Friday), 2:00 PM
Title: Impact of Eccentricity on the Performance of Nanotube Phase Change Memory Device

Abstract :

Phase Change Memory (PCM) is a promising candidate for non-volatile memory technology due to its low power consumption, high programming speed, scalability, and excellent data retention. A major challenge in PCM development is reducing the RESET current (IRESET) for low-power operation. This study investigates structural engineering, specifically nanotube PCM (NT-PCM) architecture, to address this challenge using 3-D TCAD simulations. The nanotube structure confines heat effectively, leveraging a tubular oxide or inner oxide within the Ge2Sb2Te5 (GST) active material and exhibiting higher interfacial thermal resistance (TBR GST/SiO2 = 5e-4 cm²·K/W) compared to conventional cylindrical mushroom-type devices. Results show a significant reduction in IRESET, with a 57% decrease for a 113 nm² GST/heater contact area and a 72% decrease for a 295 nm² area. However, PCM devices are highly sensitive to process variations, particularly at the nanoscale. Eccentricity, which quantifies deviations from ideal cylindrical symmetry, emerges as a critical factor influencing thermal efficiency and programming characteristics. Simulations reveal that eccentricity transitions NT-PCM cross-sections from circular to elliptical, significantly altering the GST/heater contact area and heat distribution. Among the analyzed configurations, common eccentric (CE), confocal (CF), and concentric (CC); CE and CF exhibit pronounced sensitivity, with IRESET increases of 83% and 75%, respectively, for an eccentricity of 0.83 and inner oxide diameter 5 nm. This study highlights the potential of NT-PCM devices for low-power operation while highlighting the critical need to mitigate process variations, particularly eccentricity, to achieve reliable performance in nanoscale PCM devices.