Enhanced As-Sb intermixing of GaSb monolayer superlattices in low-temperature grown GaAs

Chaldyshev, VV Bert, NA Musikhin, YG Suvorova, AA Preobrazhenskii, VV Putyato, MA Semyagin, BR Werner, P Gosele, U

Vv. Chaldyshev et al., Enhanced As-Sb intermixing of GaSb monolayer superlattices in low-temperature grown GaAs, APPL PHYS L, 79(9), 2001, pp. 1294-1296

22

INGLESE

Article

Apllied Physucs/Condensed Matter/Materiales Science

APPLIED PHYSICS LETTERS

0003-6951 → ACNP

79

9

2001

1294 - 1296

ISI

0003-6951(20010827)79:9<1294:EAIOGM>2.0.ZU;2-B

As-Sb compositional intermixing was studied by transmission electron micros copy (TEM) in GaAs films grown by molecular-beam epitaxy at low temperature (LT) and delta doped with antimony. The TEM technique was calibrated by im aging the as-grown films with delta layers containing various amounts of Sb . The calibration allowed us to deduce the effective As-Sb interdiffusion c oefficient from apparent thickness of the Sb delta layers in the films subj ected to isochronal anneals at 400-600 degreesC. The As-Sb intermixing in L T GaAs was found to be much enhanced when compared to conventional material . Its temperature dependence yields a diffusion coefficient of DAs-Sb=2x10( -14) exp(-0.62 +/-0.15 eV/kt) cm(2) s(-1). Since the kick-out mechanism ope rating under equilibrium conditions is valid for As-Sb interdiffusion in Ga As, the enhanced intermixing was attributed to an oversaturation of arsenic self-interstitials in the LT GaAs films. The effective activation energy f or As-Sb interdiffusion in LT GaAs seems to be reasonably close to the migr ation enthalpy of As interstitials, whereas their concentration was roughly estimated as 10(18) cm(-3). (C) 2001 American Institute of Physics.