3D cross-point phase-change memory for storage-class memory
We survey progress in the 3D cross-point phase-change memory (PCM) field over recent years, starting from the choice of 3D-capable access devices to candidate Ovonic threshold switching (OTS) materials, particularly with high cycling endurance and good thermal stability. First, we discuss 3D integration challenges faced when combining OTS and PCM. Then, we review the operation scheme of the OTS+PCM cross-point devices as well as the criteria that an OTS access device needs to meet (e.g. V th and I OFF) to successfully operate true cross-point array. We also review arsenic (As) and non-As-based OTS materials and discuss their properties as well as those of phase-change materials, focusing in particular on fast switching speed and long endurance compounds, which are among those proposed for storage-class memory (SCM). Finally, we briefly survey recent work on OTS integrated with PCM in stackable devices for SCM application.