Deep electron traps in organometallic vapor phase grown AlxGa1−xAs

Abstract

Deep electron traps have been studied by means of deep level transient spectroscopy in n-type nominally undoped and intentionally Te-doped AlxGa1−xAs epitaxial layers which were grown by vapor phase epitaxy from organometallic compounds (OMVPE). Three main deep electron levels are present in undoped material: a trap with an activation energy of 0.8 eV, which is also found in GaAs grown by conventional VPE, and two levels specific to OMVPE with activation energies of 0.32 and 0.38 eV, respectively. The concentration of the 0.8 eV level is found to be independent of the aluminum content x, supporting the assumption that it is not related to substitutional oxygen. The other levels, however, exhibit a very strong dependence of concentration on the composition, varying by four orders of magnitude in the range of 0⩽x⩽0.35. In Te-doped samples, a level with an activation energy of 0.23 eV has been identified, which is thought to be related to an IR emission found in photoluminescence in OMVPE as well as in liquid phase epitaxial material.

Pressure and temperature dependence of Zn incorporation in metalorganic chemical vapour deposition grown GaAs and AlGaAs using diethylzinc as precursor

“…Making devices requires multi-layer structures which consist of doped and undoped layers. As a p-type dopant the elements Zn [1][2][3][4], Mg [5][6][7], Be [8,9], Cd [10] and C [11][12][13] have been employed in MOCVD. Among these elements, zinc is the one most widely used in MOCVD growth of GaAs and AIGaAs.…”

Effect of surface morphology on the density of energy states in GaAsN grown by chemical beam epitaxy

“…12) In addition, Dejule et al reported an electron trap in GaAs grown by MBE with comparable activation energy MØØ (30 meV) and with low density. 13) For E2 and E3, some electrons traps with comparable electronic signatures were reported, such as EL10 (0.16 eV) 14) and E10 (0.17 eV), 15) EL11 (0.17 eV) 16) in vapor phase epitaxy grown GaAs, and EH2, EL3 (0.18 eV), 17,18) EL14 (0.19 eV) 19,20) in metal-organic vapor phase deposition. Furthermore, the densities of E2 and E3 were previously found to linearly decrease with increasing the As source flow rate in our GaAsN films.…”

Effect of arsenic source flow rate on the lattice defects in GaAsN grown by chemical beam epitaxy

“…This result indeed indicates that E2 and E3 may be related directly to the N atom and/or to isolated Ga vacancies in GaAsN films. For the likely reported defects in previous publications, we ould found some electrons traps with similar electronic signatures, such as EL10 (0.16 eV) [14] and E10 (0.17 eV) [15] in molecular beam epitaxy (MBE) grown GaAsN, EL3 (0.18 eV) [16], EL11 (0.17 eV) [17] in vapor phase epitaxy grown GaAs, and EH2, EL3 (0.18 eV) [18,19], EL14 (0.19 eV) [20,21] in metal-organic vapor phase deposition. However, we strongly thought that E2 and E3 forms N-related donor-like states on the basis of the temperature dependence of the junction capacitance and the As source flow rate dependence of their density [22].…”