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.
|Journal||Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films|
|Publication status||Published - Jan 1 2011|
ASJC Scopus subject areas
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films