Chemical Vapor Deposition Of Silicon Germanium Carbon Films

This thesis reports on the growth chemistry and appropriate process parameters that result in the formation of micro-crystalline silicon-germanium and silicon-carbon films. The growth technique uses an electron-cyclotron-resonance-chemical-vapor-deposition apparatus. This apparatus allows the process engineer to control such parameters as the plasma resonance plane, substrate temperature, microwave power, vacuum pressure, gas flow ratios, and gas combinations. The plasma gas is hydrogen and the precursor gases are silane and germane. The hydrogen ions and electrons in the plasma dissociate the precursor gases into radicals that give rise to film growth on the substrate. The substrate temperatures are kept below 300 C so that deposition on polyimide substrates can be performed.

Carbon (C) and Silicon Germanium (SiGe) work like a magic sauce. At least in small concentrations, they make everything taste better. It is remarkable enough that SiGe, a new material, and the heterobipolar transistor, a new device, appear on the brink of impacting the exploding wireless market. The addition of C to SiGe, albeit in small concentrations, looks to have breakthrough potential. Here, at last, is proof that materials science can put a rocket booster on the silicon-mind, the silicon transistor. Scientific excitement arises, as always, from the new possibilities a multicomponent materials system offers. Bandgaps can be changed, strains can be tuned, and properties can be tailored. This is catnip to the materials scientist. The wide array of techniques applied here to the SiGeC system bear testimony to the ingenious approaches now available for mastering the complexities of new materials

Despite the vast knowledge accumulated on silicon, germanium, and their alloys, these materials still demand research, eminently in view of the improvement of knowledge on silicon-germanium alloys and the potentialities of silicon as a substrate for high-efficiency solar cells and for compound semiconductors and the ongoing development of nanodevic

From 1995-2000, researchers at The University of Texas at Austin and the University of Wisconsin, Madison investigated and demonstrated new, intelligent manufacturing processes for growing epitaxial silicon alloy thin films that employ input from in situ optical process sensors to maintain precise control of film composition and thickness. The research team accomplished what was set forth in the original proposal. Significant progress was made in understanding the fundamental chemistry and physics of thin alloy films that affects the sensor operation and growth models, in developing and implementing state estimation and model predictive control techniques, in advancing optical sensors that can provide a complete description of the film properties, and in the design and demonstration of strained SiGe/Si and SiGeC/Si heterostructures with significant device performance enhancements over Si-based devices.

A comprehensive overview of chemical vapor deposition (CVD), an extremely versatile process for manufacturing coatings, powders, fibers, and monolithic components.