TY - JOUR
T1 - Defect engineering and atomic relocation processes in impurity-free disordered GaAs and AlGaAs
AU - Deenapanray, P. N.K.
AU - Krispin, M.
AU - Meyer, W. E.
AU - Tan, H. H.
AU - Jagadish, C.
AU - Auret, F. D.
PY - 2003
Y1 - 2003
N2 - Impurity-free disordering (IFD) of GaAs and AlxGa 1-xAs epitaxial layers using SiOx capping in conjunction with annealing was studied by deep level transient spectroscopy (DLTS) and capacitance-voltage (C-V) measurements. Three dominant electron traps S1 (E c - 0.23 eV), S2* (Ec - 0.53 eV), and S4 (E c - 0.74 eV) are created in disordered n-type GaAs. The electron emission rate of S1 is enhanced in the presence of an externally applied electric field. We propose that S1 is a defect that may involve As-clustering or a complex of arsenic interstitials, As1, and the arsenic-antisite, AsGa. S2* is shown to be the superposition of two defects, which may be VGa-related. S4 is identified as the defect EL2. Our preliminary results indicate that the same set of defects is created in disordered n-type AlxGa1-xAs, with SI pinned to the conduction band edge, while S2* and S4 are pinned relative to the Fermi level. In contrast to disordering in n-type GaAs, IFD of p-type GaAs results in the pronounced increase in the free carrier concentration in the near-surface region of the disordered layer. Two electrically active defects HA (Ev + 0.39 eV) and HB2 (Ev + 0.54 eV), which we have attributed to Cu- and As 1/AsGarelated levels, respectively, are also observed in the disordered p-GaAs layers. IFD causes segregation of Zn dopant atoms and Cu towards the surface of IFD samples. This atomic relocation process poses serious limitations regarding the application of IFD to the band gap engineering of doped GaAs-based heterostructures.
AB - Impurity-free disordering (IFD) of GaAs and AlxGa 1-xAs epitaxial layers using SiOx capping in conjunction with annealing was studied by deep level transient spectroscopy (DLTS) and capacitance-voltage (C-V) measurements. Three dominant electron traps S1 (E c - 0.23 eV), S2* (Ec - 0.53 eV), and S4 (E c - 0.74 eV) are created in disordered n-type GaAs. The electron emission rate of S1 is enhanced in the presence of an externally applied electric field. We propose that S1 is a defect that may involve As-clustering or a complex of arsenic interstitials, As1, and the arsenic-antisite, AsGa. S2* is shown to be the superposition of two defects, which may be VGa-related. S4 is identified as the defect EL2. Our preliminary results indicate that the same set of defects is created in disordered n-type AlxGa1-xAs, with SI pinned to the conduction band edge, while S2* and S4 are pinned relative to the Fermi level. In contrast to disordering in n-type GaAs, IFD of p-type GaAs results in the pronounced increase in the free carrier concentration in the near-surface region of the disordered layer. Two electrically active defects HA (Ev + 0.39 eV) and HB2 (Ev + 0.54 eV), which we have attributed to Cu- and As 1/AsGarelated levels, respectively, are also observed in the disordered p-GaAs layers. IFD causes segregation of Zn dopant atoms and Cu towards the surface of IFD samples. This atomic relocation process poses serious limitations regarding the application of IFD to the band gap engineering of doped GaAs-based heterostructures.
UR - http://www.scopus.com/inward/record.url?scp=3042631537&partnerID=8YFLogxK
U2 - 10.1557/proc-799-z2.6
DO - 10.1557/proc-799-z2.6
M3 - Conference article
AN - SCOPUS:3042631537
SN - 0272-9172
VL - 799
SP - 103
EP - 114
JO - Materials Research Society Symposium - Proceedings
JF - Materials Research Society Symposium - Proceedings
T2 - Progress in Compound Semiconductor Materials III - Electronic and Opoelectronic Applications
Y2 - 1 December 2003 through 4 December 2003
ER -