Low RESET Current Mushroom‐Cell Phase‐Change Memory Using Fiber‐Textured Homostructure GeSbTe on Highly Oriented Seed Layer
G. M. Cohen, Amlan Majumdar, Cheng‐Wei Cheng, Asit Ray, D. Piatek, L. Gignac, C. Lavoie, A. Grun, H-Y. Cheng, Z-L. Liu, H.L. Lung, Hiroyuki Miyazoe, Robert L. Bruce, M. BrightSky
Abstract
Herein, a low RESET current 1T1R mushroom‐cell phase‐change memory (PCM) device that uses fiber‐textured homostructure GeSbTe (GST) grown on highly oriented TiTe 2 seed layer is reported. The homostructure device outperformed the industry standard device, that uses doped polycrystalline GST, on most figures of merit. The homostructure devices are also benchmarked against superlattice (SL) PCM devices with 10 periods of 5/5 nm GST/Sb 2 Te 3 grown on the TiTe 2 seed layer, and are found to have same low RESET current. It is also observed by transmission electron microscopy that the alternating layers of GST/Sb 2 Te 3 and TiTe 2 /Sb 2 Te 3 in SL devices are intermixed in the switched region after the devices are cycled with RESET/SET pulses. Additionally, when the SL device is left in the SET state, the intermixed switched region crystallinity is textured and exhibits van der Waals gaps. The SL 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 artificial intelligence computation.