Nucleation promotion and kinetics on chemical vapor-deposited thin films.

摘要

The growth of thin films by chemical vapor deposition (CVD) has drawn a great attention in the past two decades, and applications of this fabrication process are now key elements in modern technologies. The importance of CVD lies primarily in its versatility for depositing a wide variety of materials as well as excellent conformal coverage on intricately shaped objects. A thorough understanding of the chemistry involved in CVD is essential in order to fully exploit the advantages that it can provide. Nucleation promotion by altering the surface activity is thus investigated and some fascinating phenomena are identified. Additionally, kinetics studies are accomplished for the deposition of a novel material by analyzing the components in the gas phase.; Chapter 1 begins with history of the development of CVD processing and a comparison with other competitive deposition techniques in industry. The various types of CVD processes currently used in production technology are also summarized in this chapter.; Chapter 2 describes a simple optical system designed for determining the induction period of Al CVD by dimethylethylamine alane (DMEAA). Two substrate pretreatment methods for nucleation promotion are evaluated using this device. Films deposited by these methods are smoother and have faster growth rates.; A procedure for real-time monitoring of aluminum film growth using the reflected laser intensity is developed in Chapter 3 to explore the phenomena observed in Chapter 2. Two simulation models are proposed to interpret the changes of reflected laser intensity during deposition. They suggest that deposition on substrates with and without the pretreatment occurs through different film growth modes.; Chapter 4 presents the discovery of a new CVD thin film material and demonstrates the evaluation of its crystal structure, composition and fundamental properties. The concentration changes of precursor in the gas phase are monitored by a mass spectrometer. The reaction kinetics and mechanisms are investigated and correlated with experimental results as compared to theoretical expectation.