Molecular Beam Epitaxial Growth Over Multiple Wafers Using an Indium-Free Mounting Technique

Abstract

ABSTRACTAn indium-free substrate mounting technique was developed for a 190-mm diameter substrate holder on which three 3-inch GaAs substrates are mounted. Reduction of the heat conduction between the substrates and the holder kept the temperature variation in the substrate within ±5° C. Highly uniform epitaxial layers were grown with low residual impurity concentrations using this technique. The variations in layer thickness and carrier concentration of Si-doped GaAs and AlGaAs epitaxial layers were within ±1% over the substrate holder. High mobility of a two-dimensional electron gas in a selectively doped GaAs/N-AlGaAs heterostructure was obtained uniformly over three 3-inch wafers. Since the holder was designed to hold the wafers without stress, no stress-related degradation of the surface morphology was observed.