Low reset current mushroom cell phase‐change memory (PCM) using fiber‐textured homostructure GeSbTe on highly oriented seed layer

Abstract

We report a low reset current 1T1R mushroom cell phase‐change memory (PCM) device that uses fiber‐textured homostructure GeSbTe (GST) grown on highly‐oriented TiTe2 seed layer. The homostructure device outperformed the industry standard device, that uses doped polycrystalline GST, on most figures of merit. The homostructure devices were also benchmarked against superlattice PCM devices with 10 periods of 5/5nm GST/Sb2Te3 grown on the TiTe2 seed layer, and were found to have same low reset current. We also observed by TEM that the alternating layers of GST/Sb2Te3 and TiTe2/Sb2Te3 in superlattice devices is intermixed in the switched region after the devices are cycled with reset/set pulses. Additionally, when the superlattice device is left in the set state the intermixed switched region crystallinity is textured and exhibits van der Waals gaps. The superlattice PCM devices require a precise layered structure that is hard to yield on a full wafer scale. In contrast, fiber‐textured homostructure PCM cells reported here are easily manufacturable, while providing similarly low reset current and low resistance drift which makes this device suitable for analog AI computation.This article is protected by copyright. All rights reserved.