Effect of substrate temperature on the deposition of Al-doped ZnO thin films using high power impulse magnetron sputtering

TL;DR

This study investigates how substrate temperature affects the electrical and structural properties of Al-doped ZnO thin films deposited via high power impulse magnetron sputtering, revealing optimal conditions for conductivity and stability.

Contribution

It demonstrates that high substrate temperatures improve film crystallinity and electrical performance while maintaining process stability at various oxygen pressures.

Findings

Lowest resistivity achieved at 600°C substrate temperature

Improved crystallinity enhances electrical mobility and moisture stability

HiPIMS process remains stable at high oxygen partial pressures

Abstract

Al-doped ZnO thin films were deposited using reactive high power impulse magnetron sputtering at substrate temperatures between room temperature and 600 $\bullet$ C. Two sample series with different oxygen partial pressures were studied. The films with the lowest resistivity of 3 x 10 -4 $\Omega$cm were deposited at the highest substrate temperature of 600 $\bullet$ C. The improvement of the electrical properties could be related to an improvement of the mobility due to the improved crystallinity. This improved crystallinity also increased the stability of the films towards ambient moisture. On the other hand, the detrimental influence of negative oxygen bombardment could be avoided, as the HiPIMS process can take place in the metal or transition mode even at relatively high oxygen partial pressures.