I am experiencing high n type background doping levels in my MOCVD process when I grow GaAs and AIGaAs devices. I think the problem is in the arsine I use. I'm buying the best grade available. What can I do?
Higher background levels of n type dopants in GaAs and AlGaAs structures are caused by trace levels of germanium, silicone and sulfur species present in the arsine. As customer applications evolve, the purity requirements for arsine must as well. Until recently, background doping levels of 1015/cm3 were considered acceptable in most applications. In general, most currently available highpurity grades of arsine can satisfy these requirements. However, process changes and demand for more sophisticated devices have resulted in the need for lower background doping levels. To address these more stringent requirements, Air Products is introducing MegabitTM III arsine, our purest grade available. Our new Megabit III arsine has significantly reduced the amounts of germanium, silicon and sulfur species. Testing done at an independent laboratory proved the effectiveness of Megabit III on thick gallium arsenide films, with excellent results. In all cases, the background doping level was <<1014/cm3. Our research has shown that Air Products' Megabit III arsine will perform more consistently and produce fewer defects in our customers' finished products. Click here for product information.
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