Investigation of SiC clean surface and Ni/SiC interface using scanning tunneling microscopy

We have studied 6H-SiC(0 0 0 1)Si surfaces with and without Ni atoms on top. 6H-SiC(0 0 0 1) clean surfaces were obtained by resistive heating of a SiC sample for a few minutes at about 1100 °C in UHV. Structural change of such clean 6H-SiC(0 0 0 1) surface was studied by scanning tunneling microscope (STM) after heat treatment at several temperatures. Then we deposited 1–2 Å of Ni on thus cleaned surface. The initial stage of the adsorption process of Ni atoms on 6H-SiC(0 0 0 1) substrate was analyzed using STM to clarify Ni islands formation. Furthermore, we heated Ni(1–2 Å)/6H-SiC(0 0 0 1)Si specimens at 400–800 °C. After heating at 600 °C, 2√3×2√3 surface structure was observed. Structure model of this surface has been proposed.