High-temperature scanning tunneling microscopy study of the '16 x 2'doubleleft right arrow(1 x 1) phase transition on an Si(110) surface

High-temperature scanning tunneling microscopy (HTSTM) has been applied to analyze the mechanism of a reversible phase transition between the '16 x 2' structure and the 1 x 1 structure appearing on a clean Si(110) surface. Th e '16 x 2' structure is the dominant structure on the clean Si(110) surface at room temperature. It has also been shown that the (17,15,1)2 x 1 steps, whose length is 5 nm in the < 111 > direction, exist in the domain of the '16 x 2' structure. The transition '16 x 2' +(17,15,1)2 x 1 step double lef t right arrow (17,15,1)2 x 1 double left right arrow1 x 1 is observed upon heating, where the first process starts at 968 K and the second finishes at 1043K. The temperature width between the phase transition is about 80 K. F rom taking account of the two processes of the transitions, we can say that the system undergoes at first the Ising transition and, at a higher temper ature, a roughening transition. Namely, T-c (= 968 K) is the temperature fo r the Ising transition and T-R(= 1043 K) is that for the roughening transit ion. (C) 2000 Elsevier Science B.V. All rights reserved.