Blister formation of tungsten due to ion bombardment

Blisters formed at tungsten surfaces due to deuterium ion bombardment have been studied systematically in the energy range 100 eV to 1 keV. The bombardment with I keV D+ at room temperature (RT) shows that the blister size increases and the number decreases with the deuterium fluence from 1 X 10(19) to 1 X 10(21) D+/cm(2). No blisters are found at elevated temperatures between 600 and 800 degreesC. For bombardment with an energy as low as 100 eV, blisters are observed at the high fluence of 1 x 10(21) D+ /cm(2). The blister size increases and the number decreases with the bombardment energy. Combined with scanning electron microscopy (SEM) ion beam depth profiling measurements have been used to investigate the effect of blister formation on the trapping behavior of deuterium in tungsten. Double implantations, where 4 keV He+ and 100 eV D+, respectively, were injected in W prior to the bombardment of I keV D+ show a pronounced increase of deuterium retention and blister disappearance. Possible mechanisms are proposed to describe the observed phenomena. (C) 2001 Elsevier Science B.V. All rights reserved.