Ultra-low energy SIMS analysis of boron deltas in silicon

Measuring depth resolution in secondary ion mass spectrometry is of crucial importance. In the case of boron in silicon, the depth resolution is frequently inspected by profiling molecular beam epitaxy (MBE) grown multi-delta-like structures. Recently, it has been shown that the quality of such samples is dependent on the growth parameters. In this paper, we show that samples grown by reduced pressure-chemical vapor deposition feature a lower dynamic range but a superior high intensity sharpness compared to MBE. Thanks to this, the depth resolution parameters reported here are excellent: the full-width at half-maximum is equal to 1.29 nm and the exponential decay length at the trailing edge to 0.64 nm for a 500 eV O-2(+) primary beam at theta = 44degrees with some oxygen flooding. We are even able to discriminate between two B deltas only 1.71 nm apart. (C) 2002 Elsevier Science B.V. All rights reserved.