Angle dependent sputtering and dimer formation from vanadium nitride target by Ar⁺ ion bombardment

A compact angle-resolved secondary ion mass spectrometer (AR-SIMS) with a special geometrical configuration, composing of a differentially pumped micro-beam ion-gun, a tillable sample stage and a time-of-flight (TOF) mass spectrometer was applied to measure angular distribution (AD) of secondary ions ejected from VN by oblique 3 keV Ar⁺ sputtering at room temperature. AD of V⁺ was almost identical with that of N⁺, strongly suggesting that Gibbsian segregation did not take place during sputtering. Since the angular dependence of VN Yv⁺ and V₂ ⁺/V⁺ intensity ratios was independent of that of N ⁺ and V⁺ intensities, VN⁺ and V ₂⁺ dimer ions were generated via the "as such" direct emission process.