Real-time scanning tunneling microscopy observation of Si(100)-(2x1)->(2xn)-> c(4x4) structural phase transitions

Abstract

We report on the discovery of Si(100)-(2 x 1)-->(2 x n)-->c(4 x 4) structural phase transitions. Annealing the Si(100)-(2 x 1) surface between 590 and 700 degrees C for some hours causes dimer vacancies to increase and nucleate into chains, ultimately forming the (2 x n) structure. After further annealing. c(4 x 4) areas appear grow. and finally cover the entire surface. Experimental results raise the possibility not only that c(4 x 4) is a stable low-temperature structure of Si(100), but that (2 x 1) is a high-temperature phase stabilized at room temperature owing to its kinetic limitations. (C) 1998 Elsevier Science B.V.