Surface roughening, sputtering

Sputter-induced Roughness. Sputtering single crystal semiconductors, in particular II-VI semiconductors, with Cs" ions results in surface roughening. There is currently no satisfactory explanation of this effect. This effect, and the corresponding reduction of the depth resolution, can be avoided by rotating the sample during the measurement. 

SIMS is inherently damaging to the sample since ion bombardment removes some material from the surface. However, other forms of damage may also occur. These include surface roughening, knock-on effects, preferential sputtering, decomposition, and implantation of source ions [49]. 

In this contribution I will exemplify the power of TDS on some model systems p-quaterphenyl (p-4P) on Au(lll) and p-hexaphenyl (p-6P) on Au(lll), mica(OOOl) and KCl(OOl). I will particularly show that the chemical composition (carbon contamination) and the morphology (surface roughening by sputtering) of the substrate surface can have a tremendous effect on the thin film growth. 

Sputtering can also modify the lattice structure in the form of amorphization and re-crystallization, and introduction of surface roughening. This can occur on both single-component and multicomponent solids. Again, single-component solids are discussed only for the sake of simplicity. 

Correlations suggest that the reduction in sputter rates observed stems from surface roughening. This would be expected as the face of the ripple facing the incoming ion beam will exhibit a reduced angle with respect to the ion beam. Any variation in the sputter rate will also modify the steady-state concentration of ions implanted during sputtering, which will further affect sputter rates. 

In the case of single crystal substrates (this includes single crystal regions within polycrystaUine substrates), different types of surface roughening are noted. These are dependent on the substrate type and the sputtering conditions applied. 

Sputter texturing Surface roughening by preferential sputtering of crystallographic planes or due to isolated inclusions or patches of low sputtering-yield material on the surface. See also Cone formation. 

Among the possibilities are the effect of the weather and atmospheric pollution on the properties of the exposed surfaces of components. They will become roughened and will adsorb increasing amounts of moisture and conductive impurities. Surface discharges may occur which will result in further deterioration due to local high temperatures and the sputtering of metallic impurities from attached conductors. 

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