SILICON (3) 7X7 STRUCTURE

The Si(111) 7 × 7 structure has been observed within 9 sec of cleaving Si crystals at 850°C. Analysis shows that sufficient Fe to be regarded as essential for the structure cannot diffuse from the bulk in the time, although Li or Cu could. Sufficient contamination to form 1% of a monolayer could form by surface diffusion from the crystal sides, provided surface diffusion coefficients considerably greater than 5 × 10 -5 cm2 sec-1 at 750°C were applicable. © 1969 The American Institute of Physics.