Experimental Evidence of the Vacancy-Mediated Silicon Self-Diffusion in Single-Crystalline Silicon

Abstract

We have determined silicon self-diffusivity at temperatures 735-875 degrees C based on the Raman shift of longitudinal optical phonon frequencies of diffusion annealed 28Si/30Si isotope superlattices. The activation enthalpy of 3.6 eV is obtained in such low temperature diffusion annealing. This value is significantly smaller than the previously reported 4.95 eV of the self-interstitial mechanism dominating the high temperature region T>>855 degrees C and is in good agreement with the theoretical prediction for the vacancy-mediated diffusion. We present a model, containing both the self-interstitial and the vacancy terms, that quantitatively describes the experimentally obtained self-diffusivity between 735 and 1388 degrees C, with the clear crossover of the two diffusion mechanisms occurring around 900 degrees C.

Diffusion ofn-type dopants in germanium

“…[52][53][54] More recently, experiments on self-diffusion in Ge have been extended to lower temperatures 14 to verify whether the dominant mechanism of self-diffusion changes as in the case of Si. [55][56][57] Utilizing isotopically modulated 70 Ge/ nat Ge multilayer structures, the diffusional intermixing at the 70 Ge/ nat Ge interface was detected down to 429 C by means of neutron reflectometry.…”

Isotope engineering of silicon and diamond for quantum computing and sensing applications

“…[43] Some electron doublequantum dots were fabricated using the strained silicon. [44] Other isotopically controlled silicon low-dimensional structures, typically grown by MBE, [45][46][47][48] have been employed, predominantly for diffusion [49][50][51][52] and amorphization [53] studies.…”

Electronic Structure and van der Waals Interactions in the Stability and Mobility of Point Defects in Semiconductors

“…However, the understanding of self-diffusion in Si remains incomplete, despite decades of seminal work on the subject . Using secondary ion mass spectrometry (SIMS), two groups obtained identical conclusions that the vacancies mechanism is preferred over the interstitials mechanism in self-diffusion at low temperature while the interstitials mechanism can be dominant at high temperature [5,6]. Correspondingly, the diffusion activation energies (sum of the formation energy and migration barrier [14][15][16][17][18][19][20][21][22][23]; however, the computation of point defect properties is still fraught with difficulties.…”

“…However, the understanding of self-diffusion in Si remains incomplete, despite decades of seminal work on the subject . Using secondary ion mass spectrometry (SIMS), two groups obtained identical conclusions that the vacancies mechanism is preferred over the interstitials mechanism in self-diffusion at low temperature while the interstitials mechanism can be dominant at high temperature [5,6]. Correspondingly, the diffusion activation energies (sum of the formation energy and migration barrier H A ¼ H f þ H m ) were H A;I ¼ 4:96 eV and H A;I ¼ 4:42 eV proposed by Bracht et al based on B, As, and P diffusion experiments [6], and H A;I ¼ 4:95 eV (extracted from the analysis of Zn diffusion in Si [8]) and H A;V ¼ 3:6 eV proposed by Shimizu et al [5].…”