Excellent Reliability Characteristics of Ovonic Threshold Switch Device with Higher‐Temperature Forming Technique

Abstract

Amorphous chalcogenide-based ovonic threshold switch (OTS) has significant potential as a selector device in high-density memory arrays. However, to realize the ideal selector device, OTS still needs to enhance its reliability characteristics such as device uniformity and threshold voltage (Vth) drift. Herein, the effect of elevated temperature forming on the selector characteristics of an OTS device is investigated. The findings indicate that the reliability performance of the device significantly improves when the forming process is conducted at higher temperature. In particular, it shows excellent Vth uniformity (sigma = 32 mV) and a notable enhancement in the Vth drift characteristics. Based on trap analysis at cryogenic temperature (77 K), it is confirmed that improved reliability characteristics can be attributed to the stability of the activated trap formed by the HT forming process.

Higher-temperature forming technology is utilized for highly reliable ovonic threshold switch devices. The distribution of threshold voltage (Vth) and device drift characteristics depending on the forming temperature is investigated. Additionally, the trap analysis in cryogenic environment for investigation of random telegraph noise characteristics is presented.image (c) 2023 WILEY-VCH GmbH