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

It has been shown that low temperature (300 degrees C) remote plasma enhanc ed processing can separately and independently control interface formation and bulk oxide deposition on silicon substrates. Plasma processing is follo wed 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 subs trates to determine if it can provide a successful pathway to device-qualit y Ge-dielectric interfaces. The new process also employs a three-step proce ss: (i) an O-2/He plasma-assisted, predeposition oxidation of the germanium surface to form a superficial germanium-oxide passivating film, (ii) depos ition of a SiO2 bulk film by remote plasma-enhanced chemical vapor depositi on from SiH4 and O-2, and (iii) a postdeposition anneal for chemical and st ructural relaxation. The resulting interfaces are improved by the predeposi tion, plasma-assisted oxidation step, but are still far too defective for d evice applications. (C) 2000 American Vacuum Society. [S0734-2101(00)13304- 4].