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Characterization of deep-level defects in GaNAs/GaAs heterostructures grown by APMOVPE

Gelczuk Ł., Dąbrowska-Szata M., Ściana B., Pucicki D., Radziewicz D., Kopalko K., Tłaczała M.

Materials Science Poland

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2016

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Vol. 34, No. 4

726--734

EN

Conventional deep level transient spectroscopy (DLTS) and high-resolution Laplace DLTS techniques were used to study electrical properties of deep-level defects in dilute GaNAs epitaxial layers grown by atmospheric-pressure metalorganic vapourphase epitaxy (APMOVPE) on the GaAs substrate. Three samples with nitrogen concentrations of 1.2 %, 1.6 % and 2.7 % were investigated. In DLTS and LDLTS spectra of the samples, four predominant electron traps were observed. On the basis of the obtained electrical parameters and previously published results, one of the traps was associated with N-related complex defects, while the other traps with common GaAs-like native defects and impurities, called EL6, EL3 and EL2.

2

Spektroskopia pojemnościowa głębokich poziomów defektowych (DLTS) w diodach Schottkyego z węglika krzemu (4H-SiC) implantowanych jonami

Gielczuk Ł., Dąbrowska-Szata M.

Elektronika : konstrukcje, technologie, zastosowania

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2012

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Vol. 53, nr 2

12-15

PL

W pracy przedstawiono wyniki badań elektrycznie aktywnych głębokich poziomów defektów wykrytych w diodach Schottky'ego na bazie 4H-SiC typu n, implantowanych jonami Al*, za pomocą metody niestacjonarnej spektroskopii głębokich poziomów (DLTS). W badanych strukturach wykryto obecność pięciu głębokich pułapek elektronowych i wyznaczono ich charakterystyczne parametry elektryczne, takie jak: energia termicznej aktywacji, przekrój czynny na wychwyt nośników i koncentracja. Nie zaobserwowano natomiast żadnych pułapek dziurawych, związanych z implantacją jonami i wygrzewaniem poimplantacyjnym. Dominujący pik sygnału DLTS przypisano obecności głębokiego centrum Z1/Z2, podstawowego rodzimego defektu występującego w strukturze SiC, ograniczającego potencjalne zastosowanie tego materiału w przyrządach dużej mocy.

EN

In the paper, DLTS study of electrically active deep-level defects revealed in the n-type and ion implanted 4H-SiC Schottky diodes was presented. In the investigated structures, five majority deep-level electron traps were revealed and their fundamental parameters, such as thermal activation energy, capture cross section and trap concentration were determined. Any minority hole traps were not observed, as it was expected after ion implantation and post-implantation annealing processes. The dominant broad peak E4/E5 was attributed to the Z1/Z2 deep-level defect, i.e. primary intrinsic defect in SiC structures, which is known to limit considerably common applications of these structures in high-power devices.

3

Electrically active defects in SiC Schottky barrier diodes

Gelczuk Ł., Dąbrowska-Szata M., Synowiec Z.

Materials Science Poland

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2011

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Vol. 29, No. 1

70--75

EN

The electrical properties of deep-level defects in real packaged SiC Schottky barrier rectifiers were studied by deep level transient spectroscopy (DLTS). One deep-level trap with an activation energy in the 0.29-0.30 eV range was revealed to be present in all the tested samples. The electrical characteristics of the trap indicate it is probably attributed to dislocations or to metastable defects, which can be responsible for discrepancies observed in I-V characteristics (see Ref. [2]).

4

Photoreflectance study of partially relaxed epitaxial InGaAs on GaAs

Motyka M., Gelczuk Ł., Dąbrowska-Szata M., Serafinczuk J., Kudrawiec R., Misiewicz J.

Optica Applicata

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2009

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Vol. 39, nr 3

561-570

EN

Room temperature photoreflectance (PR) spectroscopy and high resolution X-ray diffraction (HRXRD) have been used to investigate InxGa1-xAs layers grown compressively by MOVPE on GaAs substrates, with different composition and thickness. HRXRD reveals that all the samples are partially relaxed and In composition has been determined for each of the samples. The effects of residual strain on the optical response of the samples, namely interband transitions and the valence band splitting, were analyzed by fitting the standard line shape form to the PR data. The energies determined experimentally as a function of indium content were compared to those obtained in the framework of the elastic strain theory for pseudomorphic layers. This comparison allows us to estimate the extent of strain relaxation and to determine the residual strain values in the samples. Furthermore, we revealed that the measured residual strain ?res follows t-1/2 dependence on the epitaxial layers thickness t. This confirms the appropriateness of the nonequilibrium models (energy-balance models) for these structures.

5

Anisotropic strain relaxation and surface morphology related to asymmetry in the formation of misfit dislocations in InGaAs/GaAs heterostructures

Gelczuk Ł., Dąbrowska-Szata M., Serafińczuk J., Masalska A., Łusakowska E., Dłużewski P.

Materials Science Poland

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2008

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Vol. 26, No. 1

157--166

EN

Partially relaxed InGaAs/GaAs heterostructures with a small lattice mismatch (less than 1%), grown by metalorganic vapour-phase epitaxy have been studied by the transmission electron microscopy, atomic force microscopy as well as X-ray diffractometry. A regular network of 60st.?misfit dislocations formed at the (001) interface in two orthogonal <110>?crystallographic directions has been revealed. A close correspondence between distribution of the interfacial misfit dislocations and undulating surface morphology in the form of a characteristic cross-hatch pattern has been observed. The structural analysis applied for the samples oriented either in [110] or [110] perpendicular directions, using reciprocal lattice mapping, revealed anisotropic strain relaxation, related to the asymmetry in the formation of alfa ?and beta ?misfit dislocations along these both directions, respectively.

6

Distinguishing and identification of point and extended defects in DLTS measurements

Gelczuk Ł., Dąbrowska-Szata M., Jóźwiak G.

Materials Science Poland

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2005

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Vol. 23, No. 3

625--641

EN

The convenient and simple criteria which enable us to distinguish between deep level point and extended defects (e.g. dislocations) in DLTS measurements have been proposed. This approach is based on earlier reports of several authors and our own experiences in the field of DLTS measurement data analysis, for III-V semiconductors. It consists of standard DLTS measurements widened by line shape and line behaviour analysis as well as capture kinetics measurements. In the first part, the paper includes a survey of the literature on analysis of the DLTS-signal coming from dislocations. In the second part, selected experimental data on distinguishing and identification of deep point and extended defects, detected in GaAs/GaAs and InGaAs/GaAs heterostructures, have been presented.

7

Badanie głębokich poziomów domieszkowych w strukturach AIIIBV metodą niestacjonarnej spektroskopii głębokich poziomów (DLTS)

Gelczuk Ł., Dąbrowska-Szata M.

Elektronika : konstrukcje, technologie, zastosowania

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2003

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Vol. 44, nr 10

3-8

PL

W pracy omówiono właściwości elektronowe i podstawowe parametry głębokich poziomów defektowych. Przedstawiono główne założenia metody lock-in DLTS i jej zastosowania do wyznaczania charakterystycznych parametrów głębokich poziomów. Omówiono podstawowe podzespoły stanowiska pomiarowego. Przedstawiono wyniki pomiarów sygnału DLTS w funkcji temperatury w strukturach n-GaAs z warstwą epitaksjalną. Wyznaczono energie aktywacji i przekroje czynne na wychwyt nośników. Zidentyfikowano wykryte poziomy pułapkowe.

EN

In this paper, the electron-properties and fundamental parameters of deep level defects have been discussed. The main assumptions of loc-k-in DLTS technipue and its application to determination of characteristic parameters of deep levels have been described. The basics components of the DLTS set up have been discussed. The results of temperature scan mode for DLTS signal measurements in n type GaAs structures with an epitaxial layer have been presented. The activation energies and the capture cross sections have been also determined. Ali the detected deep level traps have been identified.