A tray for an ampoule of a delivery system of solid precursor materials used in Atomic Layer Deposition (ALD) processes, Chemical Vapor Deposition (CVD) processes or both. The tray is configured to be able to have a reduced profile size when compressed to enhance the ease of which the tray can be inserted into the ampoule, and the tray is configured to expand in size to make improved contact with inner wall surfaces of the ampoule to provide improved heat transfer from the inner wall to the tray and ultimately to the solid precursor materials disposed on the tray.