Thermally Stable and High-Speed Ge-Te Based Ovonic Threshold Switching Selector With a Ge Intercalated Structure

Abstract

Thermal stability and switching speed of ovonic threshold switching (OTS) selector are key elements for its high-speed memory application. However, current methods tend to introduce over complicated elements and even toxic elements which will improve fabrication process complexity and be environment unfriendly. In this work, we studied a Ge-Te based OTS selector with Ge intercalated layers inserted in OTS layer. Through Poole-Frenkel model fitting, we found that the Ge intercalated layers introduced energy barrier, reducing device off-current while improving its thermal stability. The optimized device showed a thermal stability improvement of more than 180°C. In the meantime, the optimized device had good switching performance with fast switching speed of 8.2 ns, low off-current of 10 nA, and endurance of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${1}.{3} \times {10}^{{10}}$ </tex-math></inline-formula> . After a 350°C annealed process, the device performance showed good uniformity and almost no degradation. This work provides experiment guidance of the high thermal stability requirement for OTS selectors.