Effect of substrate and substrate temperature on microstructure of magnetron sputtering doped-ZnO thin films

Department of Chemistry, Indian Institute of Engineering Science and Technology (IIEST), Shibpur, Howrah-711 103, West Bengal, India

School of Applied Science and Humanities, Haldia Institute of Technology, Haldia-721 657, West Bengal, India

E-mail: himadrisekhar_das@rediffmail.com

Manuscript received online 01 October 2020, revised and accepted 31 October 2020

Al and Ga doped ZnO thin films were deposited on glass, polyethylene naphthalate (PEN) and Si substrate with variation of substrate temperature (Ts) by RF magnetron sputtering. X-Ray diffraction patterns of ZnO:Al (AZO) and ZnO:Ga (GZO) film shows strong peak (002) with a hexagonal wurtzite structure preferentially oriented along the C-axis and have a good crystallinity on Si (100) substrate. But it is observed that the peak position is shifted from its mean position for both; high and room temperature deposited films. Intrinsic stress is developed between substrate molecule and ZnO thin films and as a result; structural defects, voids, and micro-crack are observed for AZO thin film deposited at substrate temperature 400ºC due to variation of internal texture. Film strain significantly affects on its mechanical properties, cohesion properties, and electrical conductivity. Electrical resistivity came 4.9×10^–4 Ω-cm and 4.5×10^–4 Ω-cm for AZO and GZO respectively on glass substrate with optical transmission more than 90%. AZO on PEN (polyethylene terephthalate) substrate shows the resistivity of 8.6×10^–4 Ω-cm at room temperature.