Abstract: Systems and methods for providing controllable substrate-to-source arrangements in a Molecular Beam Epitaxy (MBE) system to selectively adjust a distance, orientation, or other geometric configuration as between the source(s) and substrate(s) used in epitaxial growth systems are described herein. It has been found that by controllably adjusting height, crucible type and angle, and other processing conditions, that extremely high thickness uniformity can be accomplished in epitaxially grown wafers.