OBSERVATION OF AN INTERMEDIATE CHEMICAL STATE OF SILICON IN SI-SIO2 INTERFACE BY AUGER SPUTTER PROFILING

We have observed, for the first time, a chemical state of silicon different from that of the pure bulk silicon or silicon in SiO2, using Auger electron spectroscopy. In the E N (E) spectra this state gives a major transition at 83.3 eV compared to 90.3 eV for bulk Si and 74.2 eV for SiO 2. We have observed this state both at the Si/SiO2 interface of MOS oxide structures during sputter profiling and for thin native oxides without sputtering. The state is difficult to see in the dE N (E)/dE spectra due to the presence of the sharp edge of the free silicon peak at 92 eV which tends to mask it.