Study on Solid-Phase Crystallization of Amorphized Vanadium-Doped ZnO Thin Films

作者：Watanabe Akihiro; Chiba Hiroshi; Kawashima Tomoyuki; Washio Katsuyoshi

来源：Journal of Electronic Materials, 2016, 45(4): 2008-2012.

DOI：10.1007/s11664-016-4338-3

• Zinc oxide
• vanadium
• buffer layer
• solid-phase crystallization
• RF magnetron sputtering

The effects of post-annealing and film thickness on the solid-phase crystallization (SPC) of amorphized vanadium-doped ZnO (VZO) thin films were investigated. The 2-500-nm-thick VZO (V of about 4 at.%) thin films were deposited on a c-face sapphire substrate at room temperature by RF magnetron sputtering and subsequently were annealed at an annealing temperature (T (A)) from 700A degrees C to 900A degrees C in a nitrogen atmosphere. From in-plane x-ray diffraction (XRD) measurements, the as-deposited VZO film had a faint in-plane orientation at the initial stage of deposition. However, the ZnO(100) XRD intensity weakened with increasing film thickness and no diffraction peak was seen over 35-nm thick. That is, the pseudo-amorphous film was fabricated. By annealing the 100-nm-thick VZO film over 700A degrees C, the sixfold symmetry appeared. The ZnO(100) XRD intensity increased sharply at a T (A) of 800A degrees C and was saturated at a higher T (A). The c axis orientation reached a peak at a T (A) of 800A degrees C according to the ZnO(002) XRD intensity. Concerning the effect of film thickness in the case of T (A) = 800A degrees C, both the in-plane and c axis orientation improved up to 100-nm thick and deteriorated over it. At a T (A) a parts per thousand yen 850A degrees C or film thickness a parts per thousand yen200 nm, where the c axis orientation was deteriorated, the secondary phase-like Zn3V2O8 was formed. As a result, it is found that the careful selection of the T (A) and film thickness is necessary to avoid the formation of secondary phase-like Zn3V2O8 to fabricate the high-quality buffer layer via SPC.

• 出版日期2016-4