Tuning the Thermal Properties of Hafnium Precursors by Tailoring the Ligands
Tuning the Thermal Properties of Hafnium Precursors by Tailoring the Ligands
复制标题
通过定制配体来调节铪前驱体的热性能
DOI：
--
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
A. Devi
中科院分区：
文献类型：
--
作者：
Ke Xu;A. Milanov;A. Devi
第四类金属氧化物薄膜材料(二氧化钛、氧化锆和氧化汞)因其优越的物理性能(高介电常数、折射率、硬度等)而被广泛应用于替代栅氧化物材料，如用于cmos器件、光纤、传感器、热障涂层、光波导等。金属有机化学气相沉积(MOCVD)和原子层沉积(ALD)被认为是最有吸引力的薄膜沉积方法，其中一致性和均匀性是至关重要的。MOCVD或ALD等成功的气相沉积工艺的主要挑战之一是能否获得具有适当的热和物理性质的合适的前体。最近的研究表明，胍基过渡金属和稀土金属络合物具有良好的热学性能，可以成功地作为氧化物和氮化物薄膜MOCVD和ALD的前驱体[3-6]。本研究探讨了螯合配体的配位空间体积对生成的卤基胍和酰胺基前驱体的热性能的影响。在此背景下，通过热分析对一系列Hf前驱体的物理性质进行了详细的研究。我们的工作集中在使用热重(TG)分析来研究挥发的起始温度和发生前体分解的温度区域。进行了详细的等温热重研究，以确定各络合物的蒸发速率，并分析了它们在不同设定温度下长时间保持的长期热稳定性。图1显示了已研究的四种不同的Hf化合物的比较TG数据。
Group IV metal oxide thin films materials (TiO2, ZrO2 and HfO2) find a range of potential applications such as alternative gate oxide materials for CMOS devices, optical fibers, sensors, thermal barrier coatings, waveguides etc. [1,2] owing to their advantageous physical properties (high permittivity, refractive index, hardness etc.). Metalorganic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD) are considered as most attractive thin film deposition methods where conformality, uniformity are crucial. One of the major challenges for a successful vapor deposition process such as MOCVD or ALD is the availability of suitable precursors exhibiting appropriate thermal and physical properties. Recently it has been shown that guanidinate-based transition metal and rare-earth metal complexes exhibit promising thermal properties and can successfully be employed as precursors for MOCVD and ALD of oxide and nitride thin films [3-6]. This study explores the effect of the ligand sterical bulk of the chelating ligand on the resulting thermal properties of hafnium guanidinato and amidinato based precursors. In this context, the physical properties of a series of Hf precursors have been studied in detail by thermal analysis. Our efforts concentrate on the use of thermogravimetric (TG) analysis to investigate the onset temperature of volatilization and temperature regime where precursor decomposition takes place. Detailed isothermal TG studies were carried out to determine the evaporation rates and analyse the long term thermal stability of the individual complexes when maintained at different set temperatures for long periods of time. Figure 1 shows the comparative TG data for the four different hafnium compounds that have been investigated.