Wafer cassette, and liquid phase growth system and liquid-phase growth process which make use of the same

A wafer cassette comprises a holding member having a depression corresponding to the shape of the substrate, and a cover having an opening smaller than the surface size of the substrate. The substrate is to be held in the depression by means of the holding member and the cover, and the substrate is to be covered at its one-side surface, side and all peripheral region of the other-side surface, with the holding member at its depression and with the cover at the edge of its opening. Also disclosed are a liquid-phase growth system and a liquid-phase growth process which make use of the wafer cassette.