Atomic layer deposition (ALD) of chromium oxide (Cr₂O₃) thin films is investigated in a custom built hot wall viscous flow reactor configuration at 300 °C. Chromium(III) 2,4-pentanedionate [Cr(acac)₃] and ozone (O₃) are employed as the metal and the oxygen sources, respectively. In situ quartz crystal microbalance (QCM) and ex situ x-ray reflectivity studies are utilized as the two complementary techniques to monitor the growth mechanism and self-limiting deposition chemistry during Cr₂O₃ ALD. In situ QCM studies reveal a negligible nucleation period on the previously grown Al-OH* terminated surface before revealing the perfectly linear growth mechanism at 300 °C. The saturated growth rate is found to be ca. 0.28 Å/cycle. In addition, excessive O₃ exposure also reveals an alternative, controlled, and spontaneous etching pathway of the growing film as a result of the partial surface oxidation of Cr₂O₃. The as-deposited thin films are found to exhibit a polycrystalline rhombohedral structure without any preferential orientation. X-ray photoelectron spectroscopy studies reveal uniform distribution of Cr and O throughout the stack of ca. 40 nm film with minimum C impurities. High resolution scans of Cr 2p core level also confirm the presence of Cr in the +3 oxidation state with the corresponding multiplet spectrum.

中文翻译：

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氧化铬的原子层沉积-沉积和蚀刻之间的相互作用

在定制的热壁粘性流动反应器中，在300°C下研究了氧化铬（Cr ₂ O ₃）薄膜的原子层沉积（ALD）。2,4-戊二酮酸铬（III）[Cr（acac）₃ ]和臭氧（O ₃）分别用作金属和氧源。原位石英晶体微天平（QCM）和异位x射线反射率研究被用作监测Cr ₂ O ₃ ALD过程中的生长机理和自限沉积化学的两种互补技术。原位QCM研究表明，在先前生长的Al-OH *封端的表面上，成核时间可以忽略不计，然后揭示了在300°C时完全线性的生长机理。发现饱和的增长率约为。0.28Å/周期。此外，由于Cr ₂ O ₃的部分表面氧化，过量的O ₃暴露还显示出生长膜的另一种，受控的和自发的蚀刻路径。发现所沉积的薄膜表现出多晶的菱面体结构而没有任何优先的取向。X射线光电子能谱研究表明Cr和O在整个ca堆中均匀分布。40 nm膜具有最少的C杂质。Cr 2 p的高分辨率扫描 核心能级还确认了+3氧化态下Cr的存在以及相应的多重谱。