Title :
Subthreshold Electron Transport Properties of Ultrascaled Phase Change Memory
Author :
Jie Liu ; Xu Xu ; Anantram, Manjeri P.
Author_Institution :
Dept. of Electr. Eng., Univ. of Washington, Seattle, WA, USA
Abstract :
This letter investigates the subthreshold electron transport properties of ultrascaled phase change material (PCM) GeTe, which is sandwiched by TiN electrodes, by using ab initio molecular dynamics, density functional theory, and Green´s function. Our purely ab initio simulations reproduce the measured current-voltage curve characteristics of crystalline (c-) and amorphous (a-) PCM. The ON/OFF ratio and the underlying electron transport mechanism are explained. The electron transport properties of ultrascaled c-PCM are dominated by metal-induced gap states, and the measured linear and exponential shapes of the subthreshold current-voltage curve of ultrascaled a-PCM are a consequence of both the bias window enlarging and the biasinduced change of transmission.
Keywords :
Green´s function methods; ab initio calculations; density functional theory; electrochemical electrodes; electron transport theory; germanium compounds; molecular dynamics method; phase change memories; titanium compounds; Green function; ON-OFF ratio; TiN-GeTe-TiN; ab initio molecular dynamics; amorphous PCM; crystalline PCM; density functional theory; electrode; electron transport mechanism; exponential shape measurement; linear shape measurement; metal-induced gap state; subthreshold current-voltage curve characteristics; subthreshold electron transport property; ultrascaled phase change memory; Current measurement; Phase change materials; Phase change memory; Photonic band gap; Scattering; Shape; Switches; $ab~initio$ molecular dynamics; Green´s function; Green´s function.; Phase change memory; ab initio molecular dynamics; density functional theory; device scaling;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2014.2311461
