High Temperature Stability of Si/SiO sub 2 Interfaces and the Influence of SiO Flux on Thermomigration of Impurities in SiO sub 2.

We analyze experimentally unidirectional mass transport of As implanted into a SiO sub 2 film covered with Si and heated to 1405C in a temperature gradient. The data can only be explained if we postulate that the thermomigration process is mediated by a flux of SiO molecules, flowing from the Si/SiO sub 2 interfaces into the oxide. From the delay times before the onset of As drift, we estimate diffusivity of SiO at ~4x10 sup (-13) cm sup 2 /sec at 1405C.