Doubly charged state of EL2 defect in MOCVD-grown GaAs

Naz, Nazir A.; Qurashi, Umar S.; Majid, Abdul; Iqbal, M. Zafar

doi:10.1016/j.physb.2007.08.159

Cited by 3 publications

(1 citation statement)

References 15 publications

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“…[37][38][39][40] We note first that the antisite-complex EL2 defect is commonly observed in GaAs, but its energy level is ∼0.75 eV from the GaAs conduction band edge, which is too deep to be of relevance to the LF noise measurements of this study. [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59] However, DFT calculations indicate that isolated tetrahedrally symmetric As Ga has a +/0 charge transition level that is ∼0.5 eV below the GaAs conduction band, 50 which makes As Ga a plausible candidate for the large magnitude, a wide peak at ∼0.5 eV in Fig. 9.…”

Section: Discussionmentioning

confidence: 99%

Low-frequency noise and defects in AlGaAs/InGaAs/GaAs pseudomorphic high-electron mobility transistors

Luo,

O'Hara,

et al. 2024

Journal of Applied Physics

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Current–voltage characteristics and low-frequency (LF) noise of industrial-quality AlGaAs/InGaAs/GaAs pseudomorphic high-electron-mobility transistors are evaluated as a function of bias stress and temperature. A small positive shift of threshold voltage Vth and negligible degradation in peak transconductance GM are observed under ON-state bias conditions at elevated temperatures. The Vth measurements suggest activation of an acceptor-like defect or impurity center. The GM measurements demonstrate that newly activated defects are not located close enough to the two-dimensional electron gas to scatter carriers strongly. First-principles calculations and comparisons with previous work suggest that OAs impurity centers, other oxygen-related defects, isolated AsGa antisites, and dopant-based DX centers may contribute significantly to low-frequency (LF) noise in as-processed devices. LF noise is relatively unaffected by voltage stress at elevated temperatures, consistent with the small changes in Vth and peak GM.

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Section: Discussionmentioning

confidence: 99%

Low-frequency noise and defects in AlGaAs/InGaAs/GaAs pseudomorphic high-electron mobility transistors

Luo,

O'Hara,

et al. 2024

Journal of Applied Physics

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Thermal annealing behaviour of deep levels in as-grown p-type MOCVD GaAs

Naz¹,

Qurashi²,

Iqbal³

2009

Physica B: Condensed Matter

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Effects of irradiation and annealing on deep levels in rhodium-doped p-GaAs grown by metal-organic chemical-vapor deposition

Naz

Qurashi

Iqbal

2011

Journal of Applied Physics

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This paper reports a detailed study of the effects of irradiation and thermal annealing on deep levels in Rh-doped p-type GaAs grown by low-pressure metal-organic chemical-vapor deposition, using deep level transient spectroscopy (DLTS) technique. It is found upon irradiation with alpha particles that, in addition to the radiation-induced defect peaks, all the Rh-related peaks observed in majority, as well as minority-carrier emission DLTS scans show an increase in their respective concentrations. The usually observed α-induced defects Hα1, Hα2, and Hα3 are found to have lower introduction rates in Rh-doped samples, as compared to reference samples (not doped with Rh). Alpha-irradiation has been found to decompose the two minority carrier emitting bands (one at low temperature ∼150 K and the other at ∼380 K) observed prior to irradiation into distinct peaks corresponding to deep levels Rh1 and Rh2 and EL2 and Rh3, respectively. A similar effect is also observed for the majority-carrier emitting band composed of hole emission from deep levels RhA and RhB, which separate out well upon irradiation. Further, from the double-correlation DLTS measurements, the emission rates of carriers from the radiation-enhanced peaks corresponding to deep levels Rh1, Rh2, Rh3, and RhC were found to be dependent on junction electric field. For RhC, the field dependence data have been analyzed in terms of the Poole-Frenkel model employing a 3-dimensional Coulomb potential with q = 2e (electronic charge). Temperature dependence of the hole capture cross-sections of the levels RhA and RhC was also studied quantitatively. The observed dependence of the hole capture cross-section of RhC on temperature can be interpreted in terms of multiphonon capture model, yielding a capture barrier of 0.2 eV and σ(∞) = 2.3 × 10−14 cm2. The results of irradiation and isochronal thermal annealing study, in combination with the theoretical analysis of the field dependence of hole emission data, lead us to interpret the levels RhA and RhB as charged centers and probably complexes of arsenic anti-site defect (AsGa) with Rh-impurity, (AsGa-Rh). The levels Rh1 and Rh2 are also proposed to be complexes, albeit of a different type, of arsenic anti-site defects (AsGa) and Rh-impurity (AsGa-Rh), while the level RhC is likely to be a doubly-charged complex center composed of arsenic interstitial (IAs) and Rh-impurity (IAs-Rh).

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Doubly charged state of EL2 defect in MOCVD-grown GaAs

Cited by 3 publications

References 15 publications

Low-frequency noise and defects in AlGaAs/InGaAs/GaAs pseudomorphic high-electron mobility transistors

Low-frequency noise and defects in AlGaAs/InGaAs/GaAs pseudomorphic high-electron mobility transistors

Thermal annealing behaviour of deep levels in as-grown p-type MOCVD GaAs

Effects of irradiation and annealing on deep levels in rhodium-doped p-GaAs grown by metal-organic chemical-vapor deposition

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