Solution-based processing of the phase-change material KSb5S8

A hydrazine-based process for solution-depositing phase-change materials (PCMs) is demonstrated, using KSb5S8 (KSS) as an example. The process involves dissolving the elemental metals and chalcogen in hydrazine at room temperature and spin-coating the solution onto a substrate, followed by a short low-temperature (T <= 250 degrees C) anneal. The spin-coated KSS films, which range in thickness from 10 to 90 nm, are examined using variable temperature X-ray diffraction, medium energy ion scattering (MEIS), Rutherford backscattering spectroscopy (RBS), and scanning electron microscopy (SEM). The spin-coated KSS films exhibit a reversible amorphous-crystalline transition with a relatively high crystallization temperature (similar to 280 degrees C). Selected other chalcogenide-based PCMs are also expected to be suitable for thin-film deposition using this approach.