"Stickier"-Surface SbTe Templates Enable Fast Memory Switching of Phase Change Material GeSbTe with Growth-Dominated Crystallization.

Ge-Sb-Te (GST)-based phase-change memory (PCM) excels in the switching performance but remains insufficient of the operating speed to replace cache memory (the fastest memory in a computer). In this work, a novel approach using SbTe templates is proposed to boost the crystallization speed of GST by five times faster. This is because such a GST/SbTe heterostructure changes the crystallizing mode of GST from the nucleation-dominated to the faster growth-dominated one, as confirmed by high-resolution transmission electron microscopy, which captures the interface-induced epitaxial growth of GST on SbTe templates in devices. molecular dynamic simulations reveal that SbTe templates can render GST sublayers faster crystallization speed because SbTe's "sticky" surface contains lots of unpaired electrons that may attract Ge atoms with less antibonding interactions. Our work not only proposes a template-assisted PCM with fast speed but also uncovers the hidden mechanism of SbTe's sticky surface, which can be used for future material selection.