Investigation on HfO2 properties grown by ALD using TDMAH as precursor

HfO2 films have increasingly extensive applications in optical and electronic industry. In order to obtain controllable properties of HfO2 film, its growth behavior needs to be studied. HfO2 thin films prepared by Atomic Layer Deposition (ALD) were studied in this work. Growth behavior was elucidated by controlling the cycles of ALD and characterized by both structural and optical measurements. As the increase of thickness of the film, HfO2 converts from amorphous to monoclinic and the preferred orientation of (200) and (020) lattice plane is strengthened in monoclinic phase. Oriented arrangement of atoms is relevant to the gradient structure of HfO2 film and abundant protuberant islands on the surface of HfO2 film. Annealing experiment proved the orientation of atomic arrangement in amorphous HfO2 which promotes the continuous variation of HfO2 films in refractive index (n). And the orientation arrangement eventually contributes to crystallization of the film which will significantly reduce the laser induced damage threshold (LIDT) of the film. Analysis of optical properties in this work can provide useful information for the preparation of optical coating containing HfO2.

Automated summary

This study investigates the growth behavior of HfO2 films prepared by ALD. It is found that as the thickness of the film increases, HfO2 transforms from amorphous to monoclinic phase, and the orientation of atomic arrangement is related to the surface morphology of the film.