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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on GeAsSe by Materials Project

GeAsSe crystallizes in the orthorhombic Pnna space group. The structure is two-dimensional and consists of two GeAsSe sheets oriented in the (0, 0, 1) direction. there are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to two equivalent As2- and two equivalent Se2- atoms to form corner-sharing GeAs2Se2 tetrahedra. Both Ge–As bond lengths are 2.51 Å. Both Ge–Se bond lengths are 2.39 Å. In the second Ge4+ site, Ge4+ is bonded to two equivalent As2- and two equivalent Se2- atoms to form corner-sharing GeAs2Se2 tetrahedra. Both Ge–As bond lengths are 2.50 Å. Both Ge–Se bond lengths are 2.41 Å. As2- is bonded in a distorted trigonal non-coplanar geometry to two Ge4+ and one As2- atom. The As–As bond length is 2.49 Å. Se2- is bonded in an L-shaped geometry to two Ge4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

How arsenic makes amorphous GeSe a robust chalcogenide glass for advanced memory integration

The 3D integration technology in semiconductor fabrication requires a key component, the ovonic threshold switching (OTS) selector, to suppress the current leakage. The As doped amorphous (a-) GeSe glass is a commercialized OTS material in 3D phase-change memory, but the understanding of such a doping mechanism is still inadequate. Here we systematically explore the effect of As doping on the structural, bonding, and dynamics properties of a-GeAsSe using ab initio molecular dynamics simulations. The results reveal that As atoms form strong bonds with both Ge and Se atoms. The distorted octahedral structures and the 5-fold rings linked by atoms are increased. All of these structural features lead to a more disordered configuration. Moreover, as atoms have notably slowed down the atomic mobility, rendering a-GeAsSe a high stability. Overall, our studies offer insightful understanding of As-doping in OTS materials, paving the way for the design and application of advanced selector devices.

36 MATERIALS SCIENCE↗