Nanofabrication using structure controlled hydrogenated Si clusters deposited on Si surfaces

We studied structure formation by deposition of hydrogen-saturated Si clust ers Si6H13+ and Si8H19+ on Si (111)-(7X7) surfaces using the deposition sys tem of cluster ions equipped with a scanning tunneling microscope (STM) for surface observation, The system uses a quadrupole ion trap as a mass-selec tive source of cluster ion beams and delivers to the substrate a beam of Si 6H13+ focused to 2 mm diameter with a current of similar to 100 pA for the cluster kinetic energy on impact with the surface >5 eV. It was observed th at when these clusters are deposited with suitable kinetic energy, i.e., si milar to2 eV/Si atom, the impact energy makes the clusters mobile on the su rface, leading to self-formation of cluster-agglomerated structures at step edges and along domain boundaries of (7X7) phases. Intentional manipulatio n of the deposited clusters is also possible using the STM tip; the cluster s can be accumulated to the tip position by applying bias voltage larger th an 3 V. (C) 2000 American Vacuum Society. [S0734-211X(00)16306-1].