Apparatus for providing depletion-free uniform thickness cvd thin-film

Abstract

A novel apparatus for forming depletion-free uniform thickness CVD thin-film on semiconductor wafers includes a diffusion furnace, a boat loader coupled to the furnace for loading and removing a batch of semiconductor wafers into and out of the furnace, and a semiconductor wafer support boat for removably retaining a plurality of vertically oriented semiconductor wafers on the boat. The boat includes supporting surfaces so arranged that depletion-free uniform thickness thin-film is provided on both sides of each of the vertically oriented wafers. The semiconductor wafer support boat preferably includes two laterally spaced elongated rails each having an undulatory longitudinal section defining plural ridge portions spaced apart by plural valley portions. The ridges on one of the rails are provided with transverse slots that cooperate with confronting transverse slots provided on the confronting ridge portions on the other one of the rails to define a plurality of wafer edge receiving channels. The valley portions of the walls of the rails effectively shift the depletion zone away from each wafer edge receiving channel, thereby providing depletion-free uniform thickness CVD thin-film. The system may advantageously be employed for low temperature photochemical and photosensitized vacuum chemical vapor deposition processes.