SPUTTERING PROCESSES IN ALXGA1-XAS AND THE EFFECTS ON POST-IONIZATION DETECTION

Resonance ionization mass spectrometry (RIMS) of neutral atoms and molecules sputtered from GaAs and AlxGa1-xAs is used to elucidate sputtering mechanisms. Sputter yields are measured for a variety of ion beam types, energies and angles of incidence. Although Xe+ sputtering may have greater yields than Ar+, thus removing more material per unit time for post-ionization detection, a significant fraction of molecules, e.g. Al2, are formed, reducing atomic signals. At low incident energy (2 keV) and high angle of incidence (60-degrees), Al RIMS signals are not linearly related to Al content. Possible preferential sputtering of As by Xe+ in AlAs promotes Al2 formation, thus reducing Al signals. Ar+ sputtering improves atomization efficiency.