Surface reaction kinetics of Ga 1− xIn xP growth during pulsed chemical beam epitaxy

Abstract

The understanding of thin film growth processes and their control requires the development of surface-sensitive real-time optical characterization techniques that are able to provide insight into the surface reaction kinetics during an organometallic deposition process. These insights will allow us to move the control point closer to the point where the growth occurs, which in a chemical beam epitaxy (CBE) process is a surface reaction layer (SRL), built up of physisorbed and chemisorbed precursor fragments between the ambient and film interface. This contribution presents results on parameter estimations of rate constants and optical response factors in a reduced order surface kinetics (ROSK) model, which has been developed to describe the decomposition and growth kinetics of the involved organometallic precursors and their incorporation in the film deposition. As a real-time characterization technique, we applied p-polarized reflectance spectroscopy (PRS) during low temperature growth of epitaxial Ga 1− x In x P heterostructures on Si(0 0 1) substrates by pulsed chemical beam epitaxy (PCBE). The high surface sensitivity of PRS allows us to follow alterations in composition and thickness of the SRL as they are encountered during periodic precursor supply. The linkage of the PRS response to the ROSK model provides the base for the parameter estimation, giving insights into the organometallic precursor decomposition and growth kinetics.