High vacuum chemical vapour deposition of oxides:: A review of technique development and precursor selection
High vacuum chemical vapour deposition of oxides:: A review of technique development and precursor selection
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DOI：
10.1016/j.surfcoat.2013.06.059
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发表时间：
2013-09
影响因子：
5.4
通讯作者：
Y. Kuzminykh;A. Dabirian;M. Reinke;P. Hoffmann
中科院分区：
文献类型：
--
作者：
Y. Kuzminykh;A. Dabirian;M. Reinke;P. Hoffmann
氧化物材料薄膜广泛用于各种类型的应用。选择合适的沉积方法取决于目标材料和应用。我们在此回顾高真空化学气相沉积（HV-CVD）方法，该方法可以被视为经典低压化学气相沉积（LP-CVD）和分子束外延（MBE）之间的混合技术。总结了 HV-CVD 的主要特点，并分析了其与其他技术的主要区别。前体输送系统的设计从简单的减压到多渗流源系统的演变使得 HV-CVD 方法具有多功能性。全晶圆级沉积、受控前体通量梯度的应用以及基于此的组合工艺优化是该开发的三个主要特征。在这篇文章中，对通过 HV-CVD 沉积的氧化物材料以及文献中报道的前体类型进行了全面概述。 HV-CVD 工艺中主要使用金属醇盐、金属-β-二酮盐和金属烷基化物。在我们的实验室中，以下氧化物材料已使用醇盐前体或衍生物沉积在 HV-CVD 反应器中的全晶圆基板上：TiO2、TiO2-SiO2、Al2O3、Nb2O5、Nb2O5-HfO2、LiNbO3。沉积化学和工艺效率在很大程度上取决于前体类型。由于与 LP-CVD 相比，HV-CVD 气相中分子间碰撞事件减少/不存在，因此观察到沉积过程的物理和化学方面存在显着差异。对于某些醇盐前体，观察到前体分解效率超过 95%，沉积速率高达 500 nm/h，而强氧化剂（O3 或 O2 等离子体）的存在似乎对于使用 β-二酮前体获得氧化物沉积是必不可少的。此处，沉积速率较慢，约为数十纳米/小时。该技术对新型氧化物材料的适用性的主要问题是前驱体的可用性，满足前驱体容易输送、输送系统中的化学稳定性以及高真空下基底上的吸收和分解效率的要求。
Thin films of oxide materials are widely used for various types of applications. The selection of an appropriate deposition method depends on the aimed material and application. We review here a high vacuum chemical vapour deposition (HV-CVD) method, which can be considered as a hybrid technique between classical low pressure chemical vapour deposition (LP-CVD) and molecular beam epitaxy (MBE). The principal features of HV-CVD are summarized and its main differences from other techniques analysed. The evolution of the design of precursor delivery systems from simple pressure reduction to a multiple effusion sources system has enabled the versatility of the HV-CVD method. Full wafer scale deposition, application of controlled precursor flux gradients and, based on it, combinatorial process optimisation are three main features of this development. In this contribution a comprehensive overview of oxide materials, which have been deposited by HV-CVD, and types of precursors reported in the literature is presented and analysed. Mostly metal-alkoxides, metal-β-diketonates and metal-alkyls have been utilized in HV-CVD processes. In our laboratory the following oxide materials have been deposited on full wafer substrates in HV-CVD reactors using alkoxide precursors or derivatives: TiO2, TiO2-SiO2, Al2O3, Nb2O5, Nb2O5-HfO2, LiNbO3.The deposition chemistry and the efficiency of the process vary strongly depending on the precursor type. Due to the reduced/absent intermolecular collision events in the gas phase in HV-CVD as compared to LP-CVD, substantial differences in the physics and chemistry of the deposition processes are observed. Efficient precursor decomposition with more than 95% efficiency and deposition rates up to 500 nm/h have been observed for certain alkoxide precursors, whereas the presence of strong oxidizers (O3or O2plasma) seems to be indispensable in order to obtain an oxide deposit using β-diketonate precursors. Here, slower deposition rates in the order of tens of nm/h are achieved. The main concern of the applicability of the technique for new oxide materials is the availability of precursors satisfying the requirements for easy precursor delivery, chemical stability in the delivery system, and efficiency of the absorption and decomposition on the substrate in high vacuum.