Abstract
As-Sb compositional intermixing was studied by transmission electron microscopy (TEM) in GaAs films grown by molecular-beam epitaxy at low temperature (LT) and δ doped with antimony. The TEM technique was calibrated by imaging the as-grown films with δ layers containing various amounts of Sb. The calibration allowed us to deduce the effective As-Sb interdiffusion coefficient from apparent thickness of the Sb δ layers in the films subjected to isochronal anneals at 400-600 °C. The As-Sb intermixing in LT GaAs was found to be much enhanced when compared to conventional material. Its temperature dependence yields a diffusion coefficient of DAs-Sb=2 × 10-14exp(-0.62±0.15eV/kt) cm2s-1. Since the kick-out mechanism operating under equilibrium conditions is valid for As-Sb interdiffusion in GaAs, the enhanced intermixing was attributed to an oversaturation of arsenic self-interstitials in the LT GaAs films. The effective activation energy for As-Sb interdiffusion in LT GaAs seems to be reasonably close to the migration enthalpy of As interstitials, whereas their concentration was roughly estimated as 1018cm-3.
Original language | English |
---|---|
Pages (from-to) | 1294-1296 |
Number of pages | 3 |
Journal | Applied Physics Letters |
Volume | 79 |
Issue number | 9 |
DOIs | |
Publication status | Published - 27 Aug 2001 |
Externally published | Yes |