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

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 400 degrees C due to variation of internal texture. Film strain significantly affects on its mechanical properties, cohesion properties, and electrical conductivity. Electrical resistivity came 4.9x10(-4) Omega -cm and 4.5x10(-4) Omega -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 8.6x10(-4) Omega -cm at room temperature.