Combined Ligand Exchange and Substitution Reactionsin Atomic Layer Deposition of Conformal Ge2Sb2Te5Film for Phase Change Memory Application.

Forphase change memories application, Ge–Sb–Te filmswere prepared by a stable and reliable atomic layer deposition (ALD)method. Ge(OC2H5)4, Sb(OC2H5)3, [(CH3)3Si]3Sb, and [(CH3)3Si]2Te wereused to deposit various layers with compositions that can be describedby combinations of GeTe2–Sb2Te layersincluding Ge2Sb2Te5at a substratetemperature as low as 70 °C. A shift in composition of Sb–Tefilms from Sb2Te3to Sb2Te compositionwas achieved by combining ligand exchange and substitution reactionbetween Sb in [(CH3)3Si]3Sb and Tein the Sb2Te3layer. This surface-limited ALDprocess allowed highly conformal, smooth, and reproducible film growthover a contact hole structure, highlighting the feasibility of phasechange memory applications. [ABSTRACT FROM AUTHOR]