Argon ion impact desorption cross sections of chlorine and carbon from molybdenum

Abstract

Total desorption cross sections have been measured for Cl (σ Cl) and C(σ C) on molybdenum by argon ion bombardment for an incidence angle of 60° from the surface normal. For the bombardment an ion gun with low current density ( i 0 ~ 1 × 10 −7 A cm −2) at low system pressure (~10 −9 Torr) was used. The detection was performed by AES and the data were sensitivity factor corrected. The AES analysis of the surface after adsorption showed that Mo, C and Cl contributed to more than 94% of the atomic composition. With known i 0, it is possible to obtain σ from the adsorbate signal vs ion bombardment time curve. For ion energies between 0.2 keV to 1.0 keV the measured value for σ Cl and σ C are 0.5−3 × 10 −15 cm 2 and 0.2−4 × 10 −15 cm 2, respectively. The possible effects of the surface roughness due to prebombardment are discussed.