INVESTIGATION OF THE BERYLLIUM ION-SURFACE INTERACTION

The energy and temperature dependence of self-sputtering yields of ber yllium were measured. The energy dependence of the beryllium self-sput tering yield agrees well with that calculated by Eckstein et al. Below 770 K the self-sputtering yields are temperature independent; at T-ir r. > 870 K the yield increases steeply. Beryllium samples were implant ed at 370 K with monoenergetic 5 keV hydrogen ions and with a stationa ry hydrogen plasma power flux of about 5 MW/m(2). In the fluence range of 5 x 10(22)-1.5 x 10(25) m(-2) the depth profile is shifted towards the surface with increasing fluence and the concentration of trapped hydrogen atoms is reduced from 3.3 x 10(21) to 7.4 x 10(20) m(-2). Abo ut 95% of the trapped hydrogen is located within bubbles and only simi lar to 5% is trapped as atoms, With increasing implantation fluence th e bubbles coalesce, producing channels through which hydrogen escapes.