DC reactive magnetron sputtering, annealing, and characterization of CuAlO2 thin films

Blake L. Stevens, Cathleen A. Hoel, Carolyn Swanborg, Yang Tang, Chuanle Zhou, Matthew Grayson, Kenneth R. Poeppelmeier, Scott A. Barnett

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

CuAlOx thin films were prepared at three substrate temperatures (TS =60, 300, and 600 °C) and two oxygen partial pressures (P O2 =0.5 and 2 mTorr) via dc reactive magnetron sputtering from Cu-Al 50-50 at. % alloy targets and subsequent annealing. As-deposited films with P O2 =0.5 mTorr were oxygen deficient; although the delafossite structure formed upon annealing, electrical properties were poor. Films deposited with P O2 =2 mTorr transformed into the delafossite structure and exhibited p -type conductivity after annealing under N2 at temperatures TA 750 °C. Conductivity generally increased with increasing TS and decreasing TA. A special case of P O2 =2 mTorr and low TS (60 °C) resulted in a partially crystalline oxide phase that transformed into the delafossite structure at TA =700 °C and yielded the highest conductivity of 1.8 S cm-1. In general, a TA near the phase formation boundary led to an increase in conductivity. Low-temperature hydrothermal annealing was also investigated and shown to produce mixed phase films exhibiting the delafossite structure along with CuO, AlOOH, and Al2 O3.

Original languageEnglish
Article number011018
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Volume29
Issue number1
DOIs
Publication statusPublished - Jan 1 2011

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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