Investigation of chemical mechanical polishing of zinc oxide thin films

• Published in: Applied surface science Vol. 257; no. 13; pp. 5837 - 5843
• Main Authors: Gupta, Sushant, Kumar, Purushottam, Chakkaravathi, A. Arul, Craciun, Doina, Singh, Rajiv K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.04.2011; Elsevier
• Subjects: Chemical mechanical polishing; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Mathematical analysis; Mechanical polishing; Physics; Polishing; Roughness; Surface roughness; Thin films; Transparent conducting oxide; Zinc oxide; Thin films; Zinc oxide; Chemical mechanical polishing; Transparent conducting oxide; Chemical polishing; Mechanical polishing
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2011.01.116

► Highly smooth zinc oxide thin films were demonstrated. ► Chemical mechanical polishing process for zinc oxide was developed. ► Chemical and mechanical aspect of CMP process synergistically work to demonstrate high removal rates with high surface finish. ► Modified Preston's equation was proposed. Zinc oxide has become an important material for various applications. Commercially available zinc oxide single crystals and as-grown zinc oxide thin films have high surface roughness which has detrimental effects on the growth of subsequent layers and device performance. A chemical mechanical polishing (CMP) process was developed for the polishing of zinc oxide polycrystalline thin films. Highly smooth surfaces with RMS roughness <6Å (as compared to the initial roughness of 26±6Å) were obtained under optimized conditions with removal rates as high as 670Å/min. Effects of various CMP parameters on removal rate and surface roughness were evaluated. The role of pH on the polishing characteristics was investigated in detail.