Improvement of the Properties of Direct-Current Magnetron-Sputtered Al-Doped ZnO Polycrystalline Films Containing Retained Ar Atoms Using 10-nm-Thick Buffer Layers

Junichi Nomoto; Hisao Makino; Tomohiko Nakajima; Tetsuo Tsuchiya; Tetsuya Yamamoto

doi:10.1021/acsomega.9b01761

Improvement of the Properties of Direct-Current Magnetron-Sputtered Al-Doped ZnO Polycrystalline Films Containing Retained Ar Atoms Using 10-nm-Thick Buffer Layers

ACS Omega. 2019 Aug 27;4(11):14526-14536. doi: 10.1021/acsomega.9b01761. eCollection 2019 Sep 10.

Authors

Junichi Nomoto¹, Hisao Makino², Tomohiko Nakajima¹, Tetsuo Tsuchiya¹, Tetsuya Yamamoto²

Affiliations

¹ Advanced Coating Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5-2, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
² Materials Design Center, Research Institute, Kochi University of Technology, 185 Miyanokuchi, Tosayamada, Kami, Kochi 782-8502, Japan.

Abstract

The use of a 10-nm-thick buffer layer enabled tailoring of the characteristics, such as film deposition and structural and electrical properties, of magnetron-sputtered Al-doped ZnO (AZO) films containing unintentionally retained Ar atoms. The AZO films were deposited on glass substrates coated with the buffer layer via direct-current magnetron sputtering using Ar gas, a substrate temperature of 200 °C, and sintered AZO targets with an Al₂O₃ content of 2.0 wt %. The use of a Ga-doped ZnO film possessing a texture with a specific well-defined orientation as the buffer layer was very effective for improving the crystallographic orientation, reducing the residual stress, and improving the carrier transport of the AZO films. The residual compressive stress and in-grain carrier mobility were responsible for the retention of Ar atoms by the films, as observed using an electron probe microanalyzer.