Ge diffusion on Si surfaces

Abstract

Ge diffusion on Si(100), (111), and (110) surfaces has been studied by Auger electron spectroscopy and low energy electron diffraction in the temperature range from 600 to 800• C.Surface diffusion coefficients versus temperature have been measured.

Effect of adsorbed Sn on Ge diffusivity on Si(111) surface

“…2 the temperature dependence of the Ge diffusion coefficients on the clean Si(111) surface is quoted from Ref. [8]. One can see that the Ge diffusion coefficients on a Si(111) surface with adsorbed Sn exceed those on a clean Si(111) surface by four orders of magnitude in the temperature range up to 650…”

“…For preparation of a Ge evaporation cell, the pieces of Ge were located on a Si plate, which was heated by electric current. When the pieces of Ge melted, they fastened to the surface of silicon [8]. To calibrate the Ge and Sn deposition rates, we measured the time that was necessary for the formation of the Si (111)-5×5-Ge and Si (111)-2 √ 3 × 2 √ 3-Sn surface structures.…”

Electronically enhanced surface diffusion during Ge growth on Si(100)

“…It was previously found that the temperature dependence of the Ge adatom diffusion coefficient on Si(100) could be approximated by D Si(100) ¼ 3.3 Â 10 À2 exp(À 1.2 eV/kT) cm 2 /s. 14 At a substrate temperature of 250 C without any excitation, this approximation gives D s $9 Â 10 À14 cm 2 /s. We were not able to measure D s at 250 C without applying the excitation laser, since there is no specular spot at the end of the deposition.…”

“…For example, Ge atoms have almost two times greater diffusion coefficient on Si(100) than Si(111). 14 The diffusion coefficient of Ge adatoms on Si(001) was found to be D Ge $ 2.53 Â 10 À7 exp(À 0.676 6 0.03 eV/kT) cm 2 /s in the temperature range between 650-725 C. 15 We report on the effect of laser substrate excitation on surface diffusion during the growth of Ge on Si(100) À (2 Â 1) by pulsed laser deposition. Our results show that applying the excitation laser during the growth increases the surface diffusion coefficient in a way that is exponentially dependent on laser intensity.…”

Investigation on Ge surface diffusion via growing Ge quantum dots on top of Si pillars

“…In fact, most reported experimental E a values are also obtained on GeSi wetting layer surface rather than on Si surfaces. 13,14,28 Finally, we would like to discuss the value of the attempt frequency γ obtained by the fittings as shown in Fig. 4, which is about 10 15 Hz for τ being one quarter of the growth time for 1ML Ge and 2.5 × 10 14 for τ being the growth time for 1ML Ge.…”