Study of electric field enhanced emission rates of an electron trap in n-type GaN grown by hydride vapor phase epitaxy

Ashraf, H.; Arshad, Muhammad; Faraz, Sadia Muniza; Wahab, Q.; Hageman, P.R.; Asghar, M.

doi:10.1063/1.3499669

Cited by 15 publications

(4 citation statements)

References 37 publications

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“…While no previous reports have been found for the hole shallow traps, the identification of electron traps similar to the one reported in this work have been reported in many previous works. [25][26][27][28][29][30] While the precise interpretation of these traps has evolved with time, in recent works on GaN devices they have been most consistently associated with Nitrogen antisites. The consistency of defects and traps energy in AlGaN and GaN materials as a function of Al composition has been analyzed by several works; in particular ref.…”

Section: Discussionmentioning

confidence: 99%

Degradation processes of 280 nm high power DUV LEDs: impact on parasitic luminescence

Trivellin

Monti

Piva

et al. 2019

Jpn. J. Appl. Phys.

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With this work we report on characterization and reliability analysis of 280 nm high power commercial LEDs emitting 18 mW at 200 mA, with a peak wavelength of 280 nm. Spectral characterization reports the presence of a main emission peak and a sideband peak separated by 0.8 eV. DLTS analysis has also been carried out identifying two different defect traps, a deep level for electrons with E a = 0.73-0.92 eV and a shallow level for holes with E a = 0.18-0.28 eV. Results from constant current degradation tests report two different degradation mechanisms, a first degradation kinetic more noticeable at high current and a second more intense kinetic correlated to the increase of a third peak at higher wavelength. The work then suggests a reasoned interpretation by comparing the results with literature.

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Section: Discussionmentioning

confidence: 99%

Degradation processes of 280 nm high power DUV LEDs: impact on parasitic luminescence

Trivellin

Monti

Piva

et al. 2019

Jpn. J. Appl. Phys.

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“…Deep level transient spectroscopy (DLTS) uses thermal emission from traps to probe defects within approximately 1.0 eV from the band edges and is sensitive to defect concentrations as small as ~10 -4 times the net shallow doping in typical circumstances. For defects with Coulomb or similar potentials for thermal emission, the presence of a strong electric field (F) within the depletion region lowers the apparent emission barrier via the Poole-Frenkel effect 19,20 . Phonon-assisted tunneling 21,22 emission can also increase the emission rate in high fields.…”

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confidence: 99%

“…For negative majority emission transients, the energy levels obtained from DLTS measurements can vary depending on the electrical field in which the defect sits during the measurement phase of the experiment which in turn changes as a function of built-in and applied bias and doping density 20,30,34,38 . As shown in Fig.…”

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confidence: 99%

Defect states and their electric field-enhanced electron thermal emission in heavily Zr-doped β -Ga2O3 crystals

Sun

Ooi

Bhattacharyya

et al. 2020

Applied Physics Letters

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Performing deep level transient spectroscopy (DLTS) on Schottky diodes, we investigated defect levels below the conduction band minima (Ec) in Czochralski (CZ) grown unintentionallydoped (UID) and vertical gradient freeze (VGF)-grown Zr-doped -Ga2O3 crystals. In UID crystals with an electron concentration of 10 17 cm-3 , we observe levels at 0.18 eV and 0.46 eV in addition to the previously reported 0.86 (E2) and 1.03 eV (E3) levels. For 10 18 cm-3 Zr-doped Ga2O3, signatures at 0.30 eV (E15) and 0.71 eV (E16) are present. For the highest Zr doping of 510 18 cm-3 , we observe only one signature at 0.59 eV. Electric field-enhanced emission rates are demonstrated via increasing the reverse bias during measurement. The 0.86 eV signature in the UID sample displays phonon-assisted tunneling enhanced thermal emission and is consistent with the widely reported E2 (FeGa) defect. The 0.71 eV (E16) signature in the lower-Zr-doped crystal also exhibits phonon-assisted tunneling emission enhancement. Taking into account that the high doping in the Zr-doped diodes also increases the electric field, we propose that the 0.59 eV signature in the highest Zr-doped sample likely corresponds to the 0.71 eV signature in lowerdoped samples. Our analysis highlights the importance of testing for and reporting on field

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“…The defects are often dependent on growth technique, e.g., ammonothermal grown GaN has low concentration of structural defects when compare to others but high concentration of impurities, see [44]. There are a lot of studies on defects in GaN grown by other techniques such as MOCVD [45]- [47], MBE [48], [49] and HVPE [50]- [52].…”

Section: Introductionmentioning

confidence: 99%

Investigation of deep levels in bulk GaN

Duc¹

2014

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The first gallium nitride (GaN) crystal was grown by hydride vapor phase epitaxy in 1969 by Maruska and Tietjen and since then, there has been an intensive development of the field, especially after the ground breaking discoveries concerning growth and p-type doping of GaN done by the 2014 year Nobel Laureates in Physics, Isamu Akasaki, Hiroshi Amano and Shuji Nakamura. GaN and its alloys with In and Al belong to a semiconductor group which is referred as the III-nitrides. It has outstanding properties such as a direct wide bandgap (3.4 eV for GaN), high breakdown voltage and high electron mobility. With these properties, GaN is a promising material for a variety of applications in electronics and optoelectronics. The perhaps most important application is GaN-based light-emitting-diodes (LED) which can produce a highbrightness blue light. Since the bandgap of GaN can be controlled by alloying it with aluminium (Al) or indium (In) for a larger or smaller bandgap, respectively, GaN is very important for optoelectronic applications from infrared to the deep ultraviolet region. There are other semiconductors with bandgap similar to GaN such as SiC, and the first commercially blue light emitting LEDs where manufactured in SiC, however, SiC has an indirect bandgap with a low efficiency of emitting photons, and today, the SiC based LEDs have been completely replaced by the considerable more efficient GaN based LEDs. One problem, which has hampered the development of GaN based devices, is the lack of native substrate of GaN. Due to that, most of the GaN based devices are fabricated on foreign substrates such as SiC or Al2O3. Growing on a foreign substrate results in high threading dislocation (TD) densities (~109 cm-2) and stress in the GaN layer due to lattice mismatch and difference of thermal expansion coefficient between GaN and the substrate. The high TD density and the stress influence the performance of the devices. Another important aspect related to GaN which has attracted manystudies is how defects affect the efficiency of GaN-based devices.Therefore, it is necessary to understand the properties and to identifythem. When we know there properties, one can estimate how they willinfluence the behavior of devices, and thereby, optimize the performance of the device for its application. Basically, a fundamental knowledge of defect properties, and how to introduce them in a controlled manner, or to avoid them, is important in order to optimize the performance of devices. Defects can be introduced both intentionally and unintentionally into semiconductors during the growth process, during processing of the device or from the working environment, for example, devices working in a radioactive ambient are more likely to have defects induced by irradiation. This thesis is focused on electrical characterization of defects in bulk GaN grown by halide vapor phase epitaxy (HVPE) by using deep level transient spectroscopy. Other measurement techniques like currentvoltage measurement (IV), capacitance-voltage measurement (CV) a...

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Study of electric field enhanced emission rates of an electron trap in n-type GaN grown by hydride vapor phase epitaxy

Cited by 15 publications

References 37 publications

Degradation processes of 280 nm high power DUV LEDs: impact on parasitic luminescence

Degradation processes of 280 nm high power DUV LEDs: impact on parasitic luminescence

Defect states and their electric field-enhanced electron thermal emission in heavily Zr-doped β -Ga2O3 crystals

Investigation of deep levels in bulk GaN

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