MOCVD growth and characterization of 100-mm diameter (Ga1-xAlx) 0.5In0.5P/GaAs epitaxial materials for LED a

摘要

Abstract: High brightness visible light emitting didoes (LEDs) based on GaAlInP/GaAs are now in great demand. In order to meet the requirements for mass production with low unit cost, metalorganic chemical vapor deposition (MOCVD) is the primary deposition process for cost effective large area and multiple wafer growth of compound semiconductors. In this work low pressure MOCVD growth and non-destructive materials characterization on 100 mm wafer size epitaxial films of quaternary GaAlInP grown on GaAs substrates for LED applications is demonstrated. The ability to scale the deposition and fabrication process from the traditionally used 50 mm to 100 mm will be key in further reducing costs. MOCVD system design requires that growth to be laterally uniform, abruptly switchable, and robust against variations in process parameters that can be achieved so that production of high quality and high uniformity GaAlInP films are obtained. In parallel, to this effort there is the need to develop rapid while wafer and non-destructive mapping characterization techniques to investigate GaAlInP materials properties such as sheet resistivity, film thickness, photoluminescence (PL), Fourier transform IR and Raman scattering spectra for both material and for the on-going qualification of material during production. Typical uniformities of GaAlInP epitaxial film thickness, sheet resistivity, major PL band peak wavelength and width are 1-3 percent. For techniques without automatic mapping abilities, multiple point measurements and employed to obtain information over the entire wafer. Variations of these characteristic features, such as sheet resistivity, PL and Raman properties, with different Al compositions and doping are discussed in this work. !17