Surface reaction kinetics of Ga1-xInxP growth during pulsed chemical beam epitaxy

The understanding of thin film growth processes and their control requires the development of surface-sensitive real-time optical characterization tec hniques 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, whic h 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 or der surface kinetics (ROSK) model, which has been developed to describe the decomposition and growth kinetics of the involved organometallic precursor s and their incorporation in the film deposition. As a real-time characteri zation technique, we applied p-polarized reflectance spectroscopy (PRS) dur ing low temperature growth of epitaxial Gal,In,P heterostructures on Si(0 0 1) substrates by pulsed chemical beam epitaxy (PCBE). The high surface sen sitivity of PRS allows us to follow alterations in composition and thicknes s 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 par ameter estimation, giving insights into the organometallic precursor decomp osition and growth kinetics. (C) 2001 Elsevier Science B.V. All rights rese rved.