New approach for the fabrication of device-quality Ge/GeO2/SiO2 interfaces using low temperature remote plasma processing

It has been shown that low temperature (300 degrees C) remote plasma enhanced processing can separately and independently control interface formation and bulk oxide deposition on silicon substrates. Plasma processing is followed by a low thermal budget thermal anneal, e.g., 30 s at 900 degrees C. In this article, this process has been modified and applied to germanium substrates to determine if it can provide a successful pathway to device-quality Ge-dielectric interfaces. The new process also employs a three-step process: (i) an O-2/He plasma-assisted, predeposition oxidation of the germanium surface to form a superficial germanium-oxide passivating film, (ii) deposition of a SiO2 bulk film by remote plasma-enhanced chemical vapor deposition from SiH4 and O-2, and (iii) a postdeposition anneal for chemical and structural relaxation. The resulting interfaces are improved by the predeposition, plasma-assisted oxidation step, but are still far too defective for device applications. (C) 2000 American Vacuum Society. [S0734-2101(00)13304-4].