High-temperature scanning tunneling microscopy study of the ‘16×2’⇔(1×1) 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 ‘16×2’ structure and the 1×1 structure appearing on a clean Si(110) surface. The ‘16×2’ structure is the dominant structure on the clean Si(110) surface at room temperature. It has also been shown that the (17,15,1)2×1 steps, whose length is 5 nm in the 〈111〉 direction, exist in the domain of the ‘16×2’ structure. The transition ‘16×2’+(17,15,1)2×1 step⇔(17,15,1)2×1⇔1×1 is observed upon heating, where the first process starts at 968 K and the second finishes at 1043 K. The temperature width between the phase transition is about 80 K. From 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 temperature, a roughening transition. Namely, Tc (=968 K) is the temperature for the Ising transition and TR (=1043 K) is that for the roughening transition.