Real-time growth monitoring of oxygen plasma enhanced ZnO atomic layer deposition using in-situ spectroscopic ellipsometry*

In this study, we use in-situ SE to monitor the real-time growth of ZnO ultrathin films fabricated by atomic layer deposition, where Zn(CH₃)₂ organometallic precursor and oxygen plasma serve as the main reactant and co-reactant, respectively. A simplistic model so-called dynamic dual box model is proposed to establish an extensive understanding of the cyclic surface modifications and the continuous growth mechanisms of ZnO thin films [1]. This makes it possible to develop reliable ALD recipes in-situ. We were able to collect in-situ SE data while growing ZnO ultra-thin films within the spectral range of 0.7-3.4 eV at a 67.9° angle of incidence. Additionally, we project that the model may be used to assess in-situ SE data that was collected during the deposition of different oxide materials. The effect of temperature on growth rate is studied to untangle its role in the thickness gain per cycle. Complementary crystallographic, chemical, and morphological investigations were performed by using x-ray diffraction, x-ray photoelectron spectroscopy, and atomic force microscopy, respectively.

References:

[1] Kilic, Ufuk, et al. "Precursor-surface interactions revealed during plasma-enhanced atomic layer deposition of metal oxide thin films by in-situ spectroscopic ellipsometry." Scientific reports 10.1 (2020): 10392.