摘要 |
A chemical vapor deposition reactor having a process chamber accommodating a substrate holder for wafers, a first gas flow of reactive gases to process the wafers and a crown-shaped gas-collector surrounding the substrate-holder, wherein said reactor further comprises: a base plate and a cover plate disposed respectively beneath and above the substrate-holder, an outer ring surrounding the gas-collector and touching both the base plate and the cover-plate, and a second flow of non-reactive gases propagating in spaces outside the process chamber limited by the base and cover plates and the outer ring, and said second flow acting as a counter-flow for preventing the first reactive gas flow to exit from the process chamber but through the gas-collector.
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