INTERACTION OF ENERGETIC OXYGEN WITH DIFFERENT BORON/CARBON MATERIALS

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