Morphology and interface characteristics of ZnO films deposited at room temperature and 750 °C

Highly c-axis oriented ZnO films have been deposited onto Si (100) substrates at room temperature (RT) and 750 °C using radio-frequency reactive magnetron sputtering. The films have been characterized with X-ray diffraction, atomic force microscopy, and transmission electron microscopy (TEM). It is found that the film deposited at RT has grains with a regular shape while the grains show an irregular shape at 750 °C. Both of the films deposited at RT and 750 °C have a crystallographic orientation relationship with the Si substrate, [110]Si//[100]ZnO and (001)Si//(001)ZnO with a deviation angle below 3°. Cross-sectional TEM images reveal that both of the ZnO films deposited at RT and 750 °C are composed of two layers. The first layer is a ZnO transition layer on the Si substrate and the second is a high c-axis oriented layer above the transition layer. The effects of substrate temperature on the growth behavior of ZnO films are discussed.