INTERACTION OF ENERGETIC OXYGEN WITH DIFFERENT BORON CARBON MATERIALS/

Pure graphite (EK 98), baron-doped graphite (3%B, 15%B, 20%B), thin ba ron/carbon layers (a-C/B:H films) and B4C were irradiated with energet ic oxygen ions of 1-5 keV to study the erosion and retention behaviour of energetic oxygen. The reaction of O+ ions with these materials lea d mainly to the formation of volatile CO and CO2 together with physica lly sputtered carbon, boron and boron oxide species. Compared with gra phite, the retention of oxygen in the boron/carbon materials is higher and the reemission of CO and CO2 is delayed after starting the bombar dment. The thermal desorption of the implanted oxygen in form of CO oc curs in addition tb the normal CO peak at 950 K in a second peak at ab out 1600 K. At these high temperatures also BO, B2O2 and B2O3 (peaked between 1200 K and 1400 K) are desorbed.