Raman study of As outgassing and damage induced by ion implantation in Zn-doped GaAs

Abstract

Room temperature micro-Raman investigations of LO phonon and LO phonon-plasmon coupling is used to study the As outgassing mechanism and the disordering effects induced by ion implantation in Zn-doped GaAs with nominal doping level p =7ϫ 10 18 cm −3 . The relative intensity of these two peaks is measured right after rapid vacuum thermal annealings (RVTA) between 200 and 450°C, or after ion implantations carried out at energies of 40 keV with P + , and at 90 and 170 keV with 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 As desorption is clearly observed in samples submitted to RVTA above 300°C, and the depletion layer depths measured in ion implanted GaAs: Zn are consistent with the damage profiles obtained through Monte Carlo simulations. Ion channeling effects, maximized for a tilt angle set to 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 100 nm in GaAs-based materials.

Raman and AFM studies of swift heavy ion irradiated InGaAs/GaAs heterostructures

“…This is in contrast to the low energy irradiations where a broad and intense disorder-activated TO (DATO) mode is observed. Also, the intensity of the symmetry allowed LO mode decreases and post-annealing is required to recover the symmetry allowed phonon modes [28][29][30][31]. This highlights that in the present work the modifications are solely by electronic energy loss and that discernible lattice damage has not been created due to irradiation.…”

Influence of Si Doping on Dislocations and Mechanical Properties of GaAs Crystals Grown by Modified Vertical Bridgman Method

“…[12][13][14] Zn-doped GaAs crystals have relatively few deep-level traps and are the main substrate materials for the preparation of light-emitting diodes and laser diodes. [15,16] In particular, Si-doped GaAs crystals are widely used to make red LEDs. [17][18][19][20] At present, commercial GaAs crystals have been grown by the liquid encapsulated Czochralski (LEC) technique, horizontal Bridgman (HB) method, vertical gradient freeze (VGF) method, with a vacuum pressure of about 10 -3 Pa.…”

“…[ 12–14 ] Zn‐doped GaAs crystals have relatively few deep‐level traps and are the main substrate materials for the preparation of light‐emitting diodes and laser diodes. [ 15,16 ] In particular, Si‐doped GaAs crystals are widely used to make red LEDs. [ 17–20 ]…”