Summary Abstract: Surface morphology of oxidized and ion-etched silicon by scanning tunneling microscopy

Abstract

Topographical changes induced by low-energy (<1 keV) ion beams are difficult to observe with conventional techniques such as scanning electron microscopy (SEM). However, such topographical changes can drastically alter the electrical properties of structures built on these surfaces, e.g., due to local changes in electric field distribution [D. J. DiMaria and D. R. Kerr, Appl. Phys. Lett. 27, 505 (1975)], and are an area of concern. We have used scanning tunneling microscopy (STM) to study the morphology of silicon (100) surfaces which have been subjected to low-energy argon-ion bombardment. The technique of STM as developed by Binnig and co-workers has recently proven to be a very valuable tool for measuring surface morphology on an atomic scale. We have obtained high resolution (0.5 Å vertical, and 10 Å lateral) topographic images which show roughening of the bombarded surfaces relative to unbombarded (control) samples. The bombarded samples display characteristic hillocks typically 50 Å in diameter and about 10 Å high.