High temperature reaction of nitric oxide with Si surfaces: Formation of Si nanopillars through nitride masking and oxygen etching

In this article, we report the fabrication of Si nanopillars by surface rea ction with nitric oxide (NO) at high temperature. NO was leaked onto clean Si surfaces, at a temperature of similar to 850 degrees C, in ultrahigh vac uum chamber and examined in situ by x-ray and ultraviolet photoelectron spe ctroscopy, Auger electron spectroscopy, low energy electron diffraction, an d ex situ by atomic force microscopy. NO molecules dissociate on the surfac e and nitrogen atoms thus produced form nitride islands. These islands act as protective masks for the etching of Si by the oxygen atoms, through the desorption of SiO species. Occurrences of these two simultaneous processes results in the formation of nanometer sized Si pillars (typical basewidth 1 00-150 nm and height 5-15 nm) capped by silicon nitride. These pillar struc tures are separated by clean Si areas as shown by the clear presence of two domains. We also show that the height of these Si pillars can be increased by ex situ chemical etching. (C) 1999 Americnn Vacuum Society. [S0734-211X (99)00304-2].