ROLE OF OXYGEN IN THE ANGULAR-DISTRIBUTION OF SPUTTERED CONSTITUENTS FROM FE CR ALLOY STUDIED BY LASER POST-IONIZATION SNMS/

Laser post-ionization sputtered neutral mass spectrometry (SNMS) has b een applied to study the angular distribution of the sputtered constit uents of Fe-40at%Cr alloys. Preferred Cr ejection was observed in the direction of the target normal under sputtering in atmosphere with a s ufficient amount of oxygen gas, while there is no distinct difference in the angular dependence of the ratio of ejected components without o xygen. Comparing the results obtained by this method with those by the thin film deposition method, it is certified that the same results ca n be attained by both methods, although in-situ measurement of the ang ular distribution of the sputtered constituents is possible only by th e laser SNMS method. This tendency is considered to be due to the form ation of Fe segregated layers on the surface of the alloy by the prese nce of oxygen.