Defect Engineering of BTe Ovonic Threshold Switch (OTS) With Nitrogen Doping for Improved Electrical and Reliability Performance
Jangseop Lee, Sanghyun Ban, Tae Hoon Lee, Hyunsang Hwang
Abstract
This study investigates the effect of N-doping on the nanoscale (d = 30 nm) BTe ovonic threshold switch (OTS) device to achieve ideal selector characteristics in terms of leakage current, cycling endurance, and variation. Based on our findings, N-doping significantly improves device performance. In particular, the N-doped BTe OTS exhibits an ultra-low leakage current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{I}_{\textit {off}}$ </tex-math></inline-formula> @ 1/2 V <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\textit {th}}$ </tex-math></inline-formula> = 750 pA), low threshold voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\textit {th}}$ </tex-math></inline-formula> ) variation ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sigma < 30$ </tex-math></inline-formula> mV), excellent cycling endurance (> 1011), and low <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\textit {th}}$ </tex-math></inline-formula> drift ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\gamma $ </tex-math></inline-formula> = 30 mV/dec.) characteristics. From density functional theory (DFT) calculation, we found that an increase in Te-Te lifetime after the N-doping process can improve the reliability characteristics of the OTS device. This study contributes importantly to the development of high-performance OTS devices, providing a fundamental understanding of the role of N-doping in enhancing device properties.