Solid-state dewetting of Pt on (100) SrTiO_3

摘要

Continuous thin films of Pt on (100) SrTiO_3 substrates were dewetted to form Pt particles at 1,150 ℃, using an oxygen partial pressure of 10~(-20) atm. After retraction of thick (50 or 100 nm) Pt films, SrTiO_3 anisotropic rods, slightly depleted in Ti, were found on the surface of the substrate. Rods did not form after dewetting of thinner (10 nm) Pt films. After dewetting, a ~10 nm thick interfacial phase was found between the Pt and the SrTiO_3. The interfacial phase, based on Sr and containing ~25 at% oxygen, is believed to be a transient state, formed due to Ti depletion from the substrate, resulting in a Pt(Ti) solution in the particles. The interfacial phase forms due to the low oxygen partial pressure used to equilibrate the system, and is expected to influence the electrical properties of devices based on Pt-SrTiO_3.