Wet Chemical Processing of (0001)Si 6H‐SiC Hydrophobic and Hydrophilic Surfaces

The wetting characteristics of polished or polished and thermally oxidized, on‐ and off‐axis (0001)Si 6H‐SiC [the silicon‐terminated surface of SiC] surfaces in selected acids and bases have been determined and compared with that of (111)Si. Auger electron and X‐ray photoelectron spectroscopies and low energy electron diffraction were used to characterize the chemical state and order of these surfaces. The oxidized SiC surfaces were hydrophilic after oxide removal with a 10:1 HF solution and were terminated with approximately a monolayer containing OH, CO, CH, and F species. The same effects were observed for the similarly treated [the carbon‐terminated surface of SiC], , and surfaces. The as‐polished SiC surfaces were hydrophobic and covered with a thin (5–10 Å) contamination layer composed primarily of C‐C, C‐F, and Si‐F bonded species. Removal of this layer using an RCA SCl etch or Piranha clean resulted in a disordered hydrophilic SiC surface. A 20 Å amorphous Si capping layer both passivated the SiC surfaces and provided a better alternative to the aforementioned contamination layer for producing hydrophobic surfaces on this material. © 1999 The Electrochemical Society. All rights reserved.