Function Of Ion Mass Research Articles

Creation of surface damage on a nickel (110) surface by bombardment with 3–30 keV noble gas ions

The creation of bombardment induced damage structures on a nickel (110) surface has been studied as a function of ion mass, ion energy and bombardment temperature. The damage creation curves which were measured with low energy ion scattering (LEIS) could be described by a function of the form N 0[1− exp(−D/D 0)] 1 2 , in which D is the bombardment dose, N 0 is the number of damage sites at saturation and D 0 is a characteristic dose. It was found that N 0 does not depend on the mass and energy of the bombarding ion or on the bombardment temperature up to 100°C. The characteristic dose D 0 depends strongly on the bombardment temperature and on the ion mass. The observed energy dependence of D 0 was rather weak. The results are discussed in terms of a model which takes into account clustering of vacancies which are created by sputtering of surface atoms and of annealing by diffusion of thermally activated adatoms.

Enhanced etching of ion-implanted silicon nitride in buffered hydrofluoric acid

The preferential etching of ion-implanted pyrolytic silicon nitride (Si3N4) and plasma-deposited silicon nitride in buffered hydrofluoric acid has been studied as a function of ion mass, energy, and dose. The dose dependence of etching enhancement produced by light ions (H and He) shows that the relevant concentration parameter is the density of displaced atoms rather than the concentration of the implanted impurity. In addition to the atomic displacement mechanism, a species-dependent contribution is seen. For Si3N4 the enhancement produced by most ions is 7, whereas P gives 15. For plasma-deposited nitride, the average enhancement is 3, with values of 8 observed for P and 1.5 for B. These enhancement values can be reduced by in situ annealing due to localized ion beam heating. This annealing occurs at bulk sample temperatures which are several hundred degrees Centrigrade lower than the temperatures required to produce the same result in a furnace anneal.

THE LUMINESCENCE RESPONSE OF PHOSPHORS TO LOW ENERGY ION BOMBARDMENT

The luminescence response of samples of ZnS:Ag and Zn2SiO4:Mn to bombardment with various ions was determined as a function of the ion energy. For ZnS:Ag, within the range of ion energies studied (E < 25 kev.), the luminescence response, L, is related to the ion energy, E, according to [Formula: see text]. E0 is a threshold energy which is not a very sensitive function of ion mass. For Zn2SiO4:Mn no threshold energy was observed except in the case of Li7+ ions, the lightest ions used with this phosphor. The experimental results for ZnS:Ag appear to be consistent with a theory in which it is assumed that the bombarding particles penetrate the phosphor as neutral atoms and produce luminescence by electronic excitation of the lattice atoms due to small impact parameter collisions.