A (2 root 3x2 root 13) surface phase in the 6H-SiC(0001) surface studied by scanning tunneling microscopy

The structure of Si-rich 6H-SiC(0001) surfaces has been investigated by sca nning tunneling microscopy (STM) and low-energy electron diffraction. We ob served a surface phase with [GRAPHICS] periodicity (designated as (2 root 3X2 root 13) for convenience), coexistin g with the known stable (3 X3) phase, in a surface obtained by annealing th e (3X3) surface at 800 degrees C. A structural model containing eight Si ad atoms per unit cell on the Si adlayer is proposed, which is consistent with the present STM images and with the extension of the (3X3) model structure . (C) 1999 American Institute of Physics. [S0003-6951(99)03731-6].