Atomic Layer Deposition of the Conductive Delafossite PtCoO₂

Abstract The first atomic layer deposition process for a ternary oxide is reported, which contains a metal of the platinum group, the delafossite PtCoO₂. The deposition with the precursors trimethyl‐Pt‐methylcyclopentadienyl, Co‐bis(N‐t‐butyl‐N′‐ethylpropanimidamidate), and oxygen plasma results in a process with a nearly constant growth rate and stoichiometric composition over a wide temperature window from 100 to 320 °C. Annealing of the as‐deposited amorphous films in an oxygen atmosphere in a temperature window from 700 to 800 °C leads to the formation of the delafossite phase. Very thin films show a pronounced preferred orientation with the Pt sheets being almost parallel to the substrate surface while arbitrary orientation is observed for thicker films. The conformal coating of narrow trenches highlights the potential of this atomic‐layer‐deposition process. Moreover, heterostructures with magnetic films are fabricated to demonstrate the potential of PtCoO₂ for spintronic applications.