This study evidences that the crystallization behavior of a thin HfO2 on Si substrate is strongly associated with its surface condition through a self-formed capping layer, which hinders the natural behaviors ofmost HfO2 films. A self-formed SiO2 layer was found on top of HfO2 by emitting Si from the SiO2 layer that was grown simultaneously at a HfO2/Si interface during annealing, inhibiting the crystallization of HfO2. The suppression of crystallization of HfO2 was also obtained by decomposing a thin 3-aminopropyltrimethoxysilane layer. We thus suggested that the surface-induced variation of crystallinity of HfO2 should be carefully concerned for device applications. (C) 2014 Elsevier B.V. All rights reserved.