Molecular Precursors for the CVD of Gallium and Indium Oxides

用于 CVD 氧化镓和氧化铟的分子前体

• 批准号: EP/F035675/1
• 负责人: Claire Jane Carmalt
• 金额: $ 51.56万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FF035675%2F1
• 关键词: Molecular; Precursors; CVD; Gallium; Indium; Molecular; Precursors; CVD; Gallium; Indium

The goal of this study is to develop new highly volatile CVD precursors to deposit gallium oxide and indium oxide films free from contamination (e.g. C, F) and for a detailed investigation of the gas sensing and TCO (thermally conductive oxide) properties of the resulting films. Gallium oxide (Ga2O3) is considered to be one of the most ideal materials for application as thin-film gas sensors at high temperature. It is thermally stable and an electrical insulator at room temperature but semiconducting above 400 oC. At temperatures above 900 oC the electric conductivity changes depend on the concentration of oxygen, hence the oxygen concentration can be detected. Oxygen gas sensors have practical use in monitoring and controlling oxygen concentrations in exhaust gases of automobiles, as well as waste gases and chemical processes. Above 400 oC Ga2O3 thin-film operates as a surface-control-type sensor to reducing gases, e.g. CO and EtOH. Therefore, it is possible to switch the function of the sensor with temperature. Indium oxide films are both transparent to visible light and conductive (TCO). Dopants (e.g. Sn) can be used to increase the conductivity of the films and to make them more suitable for applications such as in solid-state optoelectronic devices. Group 13 hydrido species possess several notable characteristics that result in them being attractive as precursors to solid-state materials. Firstly, the lack of metal-carbon bonds has the potential to reduce the amount of carbon impurities in the final material and processing temperatures can potentially be reduced due to the thermally frail metal-hydride bonds. Secondly, group 13 hydrides are attractive as precursors as they are considerably more volatile than alkyl derivatives. Thus, a range of novel volatile hydrido-gallium and indium alkoxide complexes as well as heteroleptic alkoxides will be developed. The deposition of Ga2O3 and In2O3 thin-films from the novel precursors synthesised in this programme via low pressure chemical vapour deposition (LP)CVD and aerosol assisted (AA)CVD will be investigated and the gas sensor properties of the films will be assessed. By utilising a wide range of precursors and deposition techniques we will be able to produce different microstructures and develop a correlation landscape between microstructure and gas sensing response. Indium gallium oxide (GaxInyO3) is an exceptional material for TCO applications with absolute transparency that exceed all other oxides / coupled with extremely high charge mobility. Thin-films of GaxInyO3 will be grown using combinatorial atmospheric pressure (AP)CVD and mixed nanoparticulate Ga2O3 inside host In2O3 by AACVD/APCVD from the novel precursors. We have the ability to lay down thin films using a new combinatorial APCVD reactor to make films of graded composition. This new reactor enables upto 400 different compositions to be made on a single plate in one CVD experiment. This is important as it will enable us to rapidly screen composition space in the gallium-indium oxide system and make idealised and optimised compositions for gas sensing and TCO applications. The ability to optimise composition and hence performance in a single CVD experiment would demonstrate the power of the combinatorial technique. Further we have a new reactor design for making indium oxide with embedded nanoparticles- such as gallium oxide. In this system the aerosol flow enters the deposition chamber below the APCVD gas flow, this has the benefit of allowing composite films to be made in which nanoparticles either present or generated in the aerosol droplet are embedded in the APCVD host film. This combined approach will enable us to investigate different nanoparticle densities, sizes and forms and how these effect the gas sensing properties.

这项研究的目的是开发新的高度挥发性CVD前体，以沉积氧化壳和氧化物膜无污染（例如C，F），并详细研究所得膜的气体传感和TCO（热传导氧化物）特性。在高温下，氧化甲壳（GA2O3）被认为是用作薄膜气体传感器的最理想材料之一。它是热稳定的，是室温下的电绝缘体，但半导体以上400 oC。在高于900 OC的温度下，电导率变化取决于氧气的浓度，因此可以检测到氧气浓度。氧气传感器在监测和控制汽车的排气以及废气和化学过程的氧气浓度方面具有实际使用。高于400 OC GA2O3薄膜以表面对照型传感器的运行，以减少气体，例如CO和ETOH。因此，可以用温度切换传感器的功能。氧化二膜均与可见光和导电（TCO）透明。掺杂剂（例如SN）可用于提高膜的电导率，并使它们更适合于诸如固态光电设备等应用。第13组Hydrido物种具有几种显着的特征，使它们作为固态材料的前体有吸引力。首先，缺乏金属碳键有可能减少最终材料中碳杂质的量，并且由于热脆弱的金属水合键可能会降低加工温度。其次，第13组氢化物具有吸引前体，因为它们比烷基衍生物更挥发性。因此，将开发一系列新型的挥发性氢化氢 - 烷氧化物配合物以及杂色的烷氧化物。将研究通过低压化学蒸气沉积（LP）CVD和气溶胶辅助（AA）CVD中合成的新型前体中GA2O3和In2O3薄膜的沉积，并评估膜的气体传感器性能。通过利用广泛的前体和沉积技术，我们将能够产生不同的微观结构，并在微结构和气体传感响应之间发展相关格局。氧化镁（Gaxinyo3）是具有绝对透明度的TCO应用的特殊材料，超过了所有其他氧化物 /与极高的电荷迁移率相结合。 Gaxinyo3的薄膜将使用组合大气压（AP）CVD和混合纳米刻度GA2O3在host in2O3内生长。我们有能力使用新的组合APCVD反应器来制作薄膜以制成分级成分的膜。这种新的反应器可在一个CVD实验中在单板上制成400种不同的组合物。这很重要，因为它将使我们能够快速筛选氧化物氧化衣系统中的组成空间，并为气体传感和TCO应用做出理想化和优化的组合物。优化组合物并因此在单个CVD实验中的性能的能力将证明组合技术的力量。此外，我们采用了一种新的反应器设计，用于用嵌入式纳米颗粒（例如氧化韧带）制造氧化钠。在该系统中，气溶胶流进入APCVD气流下方的沉积室，这具有允许制作复合膜的好处，其中将纳米颗粒嵌入APCVD宿主膜中。这种合并的方法将使我们能够研究不同的纳米颗粒密度，大小和形式，以及它们如何影响气体传感特性。