Redistribution of boron during thermal oxidation of silicon studied by SIMS using Ar ⁺ bombardment and the MISR method. Part I: Methodology

Quantitative depth profiling of boron through SiO 2 /Si interfaces, when profiling with Ar + , is complicated by the matrix effects. The presence of oxygen affects the sensitivity of boron by three orders of magnitude and accurate determination of the distribution of the distribution coefficient of boron at the interface is only possible when the matrix effects can be elminated or taken into account in the quantification. By using matrix‐sensitive correlation factors, a sensitivity curve of boron at different primary ion current densitites was established. This relation shows a good long‐term reproducibility. Moreover, a physical interpretation of the shape of the sensitivity curve of boron is given by comparison with pure Si and SiO 2 . Tentative explanations for the behaviour of different Si x O y z+ species in conditions of varying primary ion current density and oxygen backfill are given. The influence of the oxygen backfill pressure on the sputter rate of silicon was investigated and problems arising in the profilation of boron in SiO 2 /Si interfaces were addressed. Practical applications of the described methodology are discussed in Part II of this series.