Critical field behavior and antiband instability under controlled surface electromigration on Si(111)

Abstract

In this study we investigate step bunching and antiband surface instabilities on Si(111). We experimentally study the effects of a controlled electromigration field on the onset of antibands. We analyze the initial stage of antiband formation on step bunched surfaces under conditions of constant temperature of 1270 • C, while systematically varying the applied electromigration field. The relationship between the electromigration field and minimum terrace width required to initiate the antiband formation has been established. Also, we systematically measured values of the critical electromigration field, which is required to initiate the step-bunching process on Si(111) at 1130 • C (regime II) and 1270 • C (regime III). The dependence of the critical field on the mean atomic terrace width has been investigated and discussed.

Antiband instability on vicinal Si(111) under the condition of diffusion-limited sublimation

“…13 Therefore, when using Eq. (5), we implicitly assume that E cr = 0 and pass this assumption onto Eq.…”

“…This problem was not identified in earlier theoretical studies, where E cr was implicitly assumed to be equal zero. 26 Extrapolating the E cr (l) experimental dependence 13 shows that in the practical case of heavy desorption, this is a reasonable assumption for surfaces with a small angle of misorientation of less than 0.5 • .…”

“…These investigations demonstrate that, in the most studied third temperature regime, the critical field for Si(111) is significant and grows linearly with the increasing surface misorientation angle. 13 For example, for Si(111) with misorientation of 3 • (l = 5.7 nm) or 4 • (l = 4.3 nm), E = 2.0 V/cm is less than E cr , and the value of L m obtained with these parameters from Eq. (20) would not be physically meaningful.…”

“…It implies that for a given force F , the terrace width L t required for the onset of the antiband instability is the same for any initial interstep distance (l), which is determined by the overall surface off cut from the low index plane. The results of recent experimental investigations strongly suggest that sublimation on the Si(111) surface is a diffusionlimited process, [13][14][15] which is characterized by relatively slow surface adatom diffusion and fast kinetics at the atomic steps. Here, we provide a theoretical treatment of the antiband instability under the condition of diffusion-limited sublimation.…”

“…The weakest field was determined by the critical electromigration field (E cr ), i.e., the minimum electric field required to initiate the step bunching process. 13 Samples were diced in the shape of rectangular 20 × 1.3 mm 2 strips from n-type doped 0.525-mm-thick Si(111) wafers, with the misorientation angles (α) from the Si(111) plane in the range 1.1 • -4 • towards the direction, and the long sides of the samples aligned to the miscut direction. Initially, each sample was outgassed in a crucible for 24 hours at 700 • C. To reduce surface defects, the samples were then dc-annealed for 24 hours at a temperature of approximately 450-500 • C, which was followed by repeated dc flash-annealing up to 1250 • C for 10 seconds.…”