Chlorine incorporation and phase separation at the SiO2/Si interface during thermal oxidation of silicon in C1/O2 atmospheres

In the use of thermally grown oxides on silicon for the fabrication of metal-oxide-semiconductor (MOS) devices, mobile alkali ions introduced as contaminants adversely affect electrical stability. It has been found, however, that through the use of a gas containing chlorine in the oxidizing atmosphere, the alkali ions can be trapped and neutralized providing stable devices. But although the electrical properties of these chlorinated oxides have been well characterized, the understanding from a materials perspective is not yet complete. This paper will attempt to add to that understanding through a description of observations of the oxidation process and their rationalization in a proposed model