Raman study of As outgassing and damage induced by ion implantation in Zn-doped GaAs
Barba, D., Aimez, V., Beauvais, J., Beerens, J., Drouin, D., Chicoine, M., Schiettekatte, F.
Abstract : Room temperature micro-Raman investigations of LO phonon and LO phonon-plasmon coupling is used to study the AsAs outgassing mechanism and the disordering effects induced by ion implantation in ZnZn-doped GaAsGaAs with nominal doping level p=7×1018cm−3p=7×1018cm−3. The relative intensity of these two peaks is measured right after rapid vacuum thermal annealings (RVTA) between 200 and 450°C450°C, or after ion implantations carried out at energies of 40keV40keV with P+P+, and at 90 and 170keV170keV with As+As+. These intensities provide information regarding the Schottky barrier formation near the sample surface. Namely, the Raman signature of the depletion layer formation resulting from AsAs desorption is clearly observed in samples submitted to RVTA above 300°C300°C, and the depletion layer depths measured in ion implanted GaAs:ZnGaAs:Zn are consistent with the damage profiles obtained through Monte Carlo simulations. Ion channeling effects, maximized for a tilt angle set to 45°45° during implantation, are also investigated. These results show that the Raman spectroscopy is a versatile tool to study the defects induced by postgrowth processes in multilayered heterostructures, with probing range of about 100nm100nm in GaAsGaAs-based materials.
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