| AVS 60th International Symposium and Exhibition | |
| Nanometer-scale Science and Technology | Wednesday Sessions |
| Session NS+BI+EM-WeA |
| Session: | Nanopatterning and Nanolithography |
| Presenter: | S. Chiang, University of California, Davis |
| Authors: | M.S. van Zijll, University of California, Davis S. MacIntyre, University of California, Davis S. Chiang, University of California, Davis |
| Correspondent: | Click to Email |
Defects often act as nucleation points for island growth on surfaces. Earlier studies found that sputtering surfaces of silicon and germanium could create ordered arrays of dot and ripple structures. As a result of the sputtering and annealing cleaning procedures on Ge(110), we had previously observed the formation of pyramid structures, which could serve as engineered defects for island growth. Although these structures had some similarities to the dot patterns observed by other groups, the better defined shapes and the larger separation between the pyramid structures were striking. In an effort to better understand and control the formation of these defects, we used scanning tunneling microscopy (STM) under ultra high vacuum (UHV) conditions to measure the shapes, sizes, and spatial distribution of the observed pyramid structures on Ge(110) as a function of the argon ion sputtering energy. The samples were sputtered with low-energy ions ranging from 200eV to 500eV at an incident angle of 34o. The bases of the pyramids are rhombuses due to the 16x2 reconstruction of the Ge(110) surface. The lengths of the rhombuses range from 10 to 80nm, and the side-walls slant upward at ~4o from the horizontal. A Monte Carlo simulation of the sputtering process is used to determine the dependence of the sputtering yield on the binding energy of the surface atoms and on the incident ion energy, thereby giving insight into the process of pyramid formation.