Deuterium at the Si-SiO2 interface detected by secondary-ion mass spectrometry

Secondary-ion mass spectrometry (SIMS) has been used to measure depth profiles of deuterium in thermally grown films of SiO2 on Si. Deuterium is a readily traceable element which simulates hydrogen chemistry and thereby permits detection of effective changes in the hydrogen content of annealed oxides even in the presence of high background concentrations of hydrogen in the sputtering ambient or oxide layer. For oxidized silicon annealed in atomic deuterium, SIMS profiles clearly reveal an accumulation of deuterium at the Si-SiO2 interface. It is demonstrated that the pile-up of deuterium is not a consequence of ion migration (’’snow plowing’’) during ion sputtering.