Annealing studies of low-temperature-grown GaAs:Be

Abstract

An approximate continuum theory for interaction between dislocation and inhomogeneity of any shape and properties J. Appl. Phys. 109, 113529 (2011) Direct comparison of boron, phosphorus, and aluminum gettering of iron in crystalline silicon J. Appl. Phys. 109, 073521 (2011) Impact of type of crystal defects in multicrystalline Si on electrical properties and interaction with impurities J. Appl. Phys. 109, 033504 (2011) Low-temperature acoustic properties of nanostructured zirconium obtained by intensive plastic deformation Low Temp.The isochronal and isothermal annealing characteristics of acceptor-doped GaAs:Be grown at low substrate temperatures (300 "C) by molecular-beam epitaxy (LTMBE) have been studied. The Be was introduced in a range of concentrations from lOi to 1019 cm -3. Electrical measurements of as-grown material up to the highest Be concentration of lOI cm -3 show that no free holes are contributed to the valence band even though Raman spectroscopy of the Be local vibrational mode indicates that the majority of the Be impurities occupy substitutional sites. It is proposed that Be acceptors are rendered inactive by the high concentration of Aso,-related native donor defects present in LTMBE material. The concentration of Aso,-related defects in the neutral charge state was estimated from infrared absorption measurements to be as high as 3 X 1019 cm -3. A distinct annealing stage at 5OO.Y!, similar to that found in irradiation-damaged and plastically deformed GaAs, marks a rapid decrease in the concentration of As o,-related defects. A second annealing stage near 800 "C corresponds to the activation of Be acceptors. The presence of gallium vacancies V,, was investigated by slow positron annihilation. Results indicate an excess concentration of Voa in LTMBE layers over bulk-grown crystals. Analysis of isothermal annealing kinetics for the removal of Aso=-related defects gives an activation energy of 1.7 kO.3 eV. The defect removal mechanism is modeled with VG,-assisted diffusion of AsGa to As precipitates.

Defect identification in GaAs grown at low temperatures by positron annihilation

“…This is in accordance to the assumptions in the earlier PAS studies. [9][10][11]40,49 Due to the combination of different techniques in conjunction with theoretical calculations in the present study, the identification of V Ga can now be considered to be well established. Positron lifetime spectroscopy showed that the defects are monovacancies, whereas the conventional S -W analysis shows that they belong to the Ga sublattice.…”

“…The formation of As precipitates has often been explained in terms of a V Ga mediated diffusion of As Ga antisites. 9,19 Positron annihilation results indicate the formation of defects larger than monovacancies during annealing. 10,11 It has been suggested that positron trapping in annealed LT-GaAs is related to As precipitates 20 whereas other authors interpreted their results in terms of isolated vacancy clusters.…”

Highly mismatched GaN1−xSbxalloys: synthesis, structure and electronic properties

“…Because of the technological potential of LT-MBE GaAs, a lot of work has been performed on understanding the defects in this material [59,60,61,64,65,66,67]. In contrast only a few reports have been published on gallium nitride grown at low temperature [68,69].…”

Semiconductor materials for ultrafast optoelectronic applications

“…At that temperature the full width at half maximum of the rocking curve is the smallest for all three Be concentrations used in the experiments. At larger annealing temperatures, the lattice mismatch appears again, most probably, due to the increase of Be impurity mobility and their activation as acceptors [12]. Because Be atoms in LTG GaAs layers are substitutional, they prevent vacancy assisted diffusion of As into precipitates and stabilize As Ga defects.…”