The challenge of developing next-generation electronic devices increasingly demands control at the molecular level, which in turn depends upon a detailed understanding of the reactions driving the growth and processing of these materials. In this presentation, we will describe the use of spectroscopic techniques to monitor gas-surface reactions during semiconductor growth and modification. Two systems highlighting the approach will be discussed. The first system is the chemical vapor deposition of amorphous and microcrystalline semiconductors.

The semiconductor thin films are grown by plasma-assisted and hot-wire chemical vapor deposition, and the evolution of the structure and bonding in the films is followed under various process conditions using in situ diagnostics. Hydrogen radical-surface reactions are proposed to play an influential role in the film growth, and measurement of the temperature-dependent kinetics of these reactions will be described. In the second example, we will discuss the development of synthetic strategies for organic functionalization of semiconductor surfaces. Methods for controlling the interfacial bonding at hybrid organic/semiconductor interfaces are important for applications such as microchip-based sensors. Surface cycloaddition reactions are shown to occur readily between unsaturated hydrocarbons and the Si(100)-2x1 surface, leading to a covalently-attached organic layer and providing an important route to semiconductor surface functionalization in vacuum.