Application of ultra low energy (ULE) SIMS to emerging diamond technologies

Abstract

We report ultra low energy secondary ion mass spectrometry (ULE-SIMS) analysis of a single crystal boron delta-doped diamond layer with normal incidence O 2 + beam at incident energies of 300 eV, 500 eV and 1 keV. The diamond layer was epitaxially grown using a chemical vapor deposition (CVD) method on a synthetic single crystal diamond substrate grown using a high-temperature, high-pressure technique. The good crystalline quality of the homoepitaxal boron delta-doped layer has allowed the study of the ULE-SIMS measurement process.In contrast to the case of silicon, the transient effects on the sputter yield are very weak: we obtained a differential shift of 0.6 nm/keV -smaller than the depth measurement uncertainty (i.e. the initial erosion rate is marginally slower).The boron ion yield is independent of the incident energy and the decay length is almost so (3.0, 3.1 and 3.5 nm for 300 eV, 500 eV and 1 keV respectively), reflecting a good depth resolution possibly limited by sample structure.The erosion rate is energy independent over a wide range, but carbon ion yields are both energy and boron concentration dependent for high boron concentrations, proportional to (Y B + ) 0.85 . For this reason, care is needed with the boron quantification when the boron content is high.

Atomic spectrometry update. Atomic mass spectrometry

“…The availability of a unique single crystal, B-doped d-layer diamond sample allowed the depth profiling characteristics with normal incidence 0.3-1 keV O 2 + projectiles to be delineated. 186 In contrast to the sputtering of silicon samples, transient effects on the sputter yield were weak, resulting in a differential shift of only B0.6 nm keV À1 at a depth of B25 nm. The erosion rate and B + ion yield did not depend on the projectile energy.…”