Ion bombardment as a technique for preparation of nanometric tips from Si whickers

Oriented arrays of (111)-Si whickers grown by vapor-liquid-solid (VLS) technique on single-crystal (111)-Si substrates were subjected to ion-beam treatment. 30 keV beams of Ar+ ions were used; they were directed along the whickers axis. The average (over the cross-section of the beam) value of the ion current density ranged between 170 and 400 μA/Cm2; the average total doses were (2...6)x1018 ions/cm2. Dependence of the tip shape on ion dose was investigated by SEM-technique. Rather sharp (with curvature radii of about 50 nm) silicon tips were obtained by this method.16 refs., 4 figs