VCSEL Growth and Fabrication

Abstract

Epitaxial growth is a very critical and complex process. High quality semiconductor material resulting from epitaxial growth is an absolutely indispensable precondition for proper laser manufacturing. There are two mature technologies, which have established themselves for growth of high quality VCSEL wafers: the metal–organic chemical vapour deposition (MOCVD), sometimes called also metal–organic vapour phase epitaxy (MOVPE), and the molecular beam epitaxy (MBE). The growth process in an MOCVD reactor results from the reaction of the products, created when the growth precursors decompose on contact with the hot substrate. The main growth control parameters are gas fluxes, substrate temperature, reactor pressure and growth time. In an MBE reactor growth materials are contained separately in effusion cells in elemental form, and molecules evaporate off from the cells under high vacuum condition bringing epitaxial material to the substrate. The flux of molecules is controlled by varying the cell temperatures and operating the cell shutters.