The emission of neutral clusters in sputtering
The mass, angle and energy resolved emission of neutral clusters in sputtering was studied for a variety of metals and semiconductors. The main phenomena and results are the following: (i) Cluster emission from a series of transition metals reveals a prominent contribution of clusters to the total flux of ejected particles but there is no simple scaling of cluster intensities with the average sputtering yields. With increasing number of constituents, relative intensities of neutral clusters decrease much faster than those of secondary-ion clusters. (ii) The relative intensities of clusters emitted from amorphous and crystalline semiconductors are identical, but the energy spectra of Ge(n)- clusters (n= 1-4) sputtered from Ge (111) peak at a slightly higher energy (1 eV) as compared to spectra taken from amorphous Ge. The intensities of all Ge(n)- clusters exhibit the same dependence on emission angle; this holds for both the amorphous and crystalline Ge-sample. (iii) The flux of neutral monomers, dimers and trimers sputtered from Cu(111), Ni(111), and Ag(111) crystals shows a pronounced anisotropic emission along the <110> lattice directions which is ascribed to a momentum alignment in the anisotropic part of the collision cascade. Energy spectra taken along <110> are found to peak at higher energies than those obtained from a random emission angle.
Bibliographic Reference: Article: Applied Physics A, Vol. 48 (1989), pp. 261-271.
Record Number: 198910734 / Last updated on: 1994-12-01
Original language: en
Available languages: en