High non-additive sputtering of silicon as large positive cluster ions under polyatomic ion bombardment

Abstract

In the present work comparative studies of relative yields and mass spectra of secondary cluster Si + n ions ( n=1–17) and carbon-containing cluster Si n C + ( n=1–12) and Si n C + 2 ( n=1–6) ions sputtered from a silicon target by atomic and polyatomic Au − m projectiles ( m=1–3) with energy of 9 and 18 keV have been carried out. Anomalously high non-additivity in silicon sputtering as large positive cluster ions under polyatomic ion bombardment has been found. On the basis of the results obtained, a new method of “cluster-SIMS-cluster” registration of impurities in materials under study is proposed. This method makes it possible to increase the element analysis sensitivity more than three orders of a magnitude as compared to traditional SIMS methods.