Sic Thin Films Of Low Pressure Chemical Vapor Phase Epitaxy Growth And Microstructural Characteristics Of Study

Silicon carbide (SiC) is one of the most popular semiconductor materials with great potential in many microelectronics applications due to its excellent properties such as wide band gap, high breakdown electric field, high electron saturated drift velocity and high thermal conductivity. This dissertation reports the epitaxial growth of SiC films on different substrates (silicon, sapphire and silicon carbide) by chemical vapor deposition (CVD) technique and the influence of growth parameters on the quality of the films. The dissertation provides some important insights into the understanding of the epitaxial growth of SiC films.Chapter 1 reviews the fundamental properties and the research progress in materials and devices of SiC, which includes crystal structures, physical and chemical properties, fabrication of bulk SiC single crystal, techniques of preparing SiC films and some typical SiC devices. Among those techniques in preparing SiC films like sublimation epitaxy, pulse laser ablation deposition, molecular beam epitaxy, CVD, et al, CVD is considered to be the most successful one.Chapter 2 introduces the principles and components of the low pressure and high temperature CVD system that is the first home-made one with the highest temperature up to 1600℃. In addition, taking the gas sources (SiH₄ and C₃H₈) and carrier gas (H2) into consideration, based on the heterogeneous reaction model, a mechanism including two continuous reaction steps of the gas phase and surface is proposed.In Chapter 3, the growth of heteroepitaxial SiC films on single crystal Si substrates has been investigated. The thickness of the SiC films deposited on Si (111) substrates increases from 96 to 134 nm when the deposition temperature changes from 1150 to 1270℃. With further increasing temperature to 1350℃, however, the thickness of the films abruptly decreases to 60 nm. From the surface morphologies of the films, it is suggested that the films could be characterized by three dimensional (3D) island-like growth mode and the island-like particles be larger when temperature...