Role of barrier and buffer layer defect states in AlGaN/GaN HEMT structures

Bradley, S. T.; Young, A. P.; Brillson, L. J.; Murphy, Michael J.; Schaff, William J.

doi:10.1007/s11664-001-0004-4

Cited by 16 publications

(7 citation statements)

References 12 publications

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“…Our simulations show that only the defects in the AlGaN layer have an effect on the 2DEG density. This is consistent with previous LEEN studies looking at the impact of deep level traps in AlGaN [23]. Fig.…”

Section: Deg Density and Defect Location And Energysupporting

confidence: 93%

“…The 2DEG in AlGaN/GaN heterostructures is charge sensitive and the placement of defects affects the charge balance in the structure and thus the operation of the HEMT itself. Studies with low energy electron nanoscale spectroscopy (LEEN) have shown that the presence of deep level defects in the AlGaN layer can reduce the 2DEG confinement through a reduction in band gap [23]. Section IV of this paper will discuss the effect of defects at various energies and spatial locations within the different regions of the device.…”

Section: B Vacancies and Defects In Gan And Alganmentioning

confidence: 99%

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Electrostatic Mechanisms Responsible for Device Degradation in Proton Irradiated AlGaN/AlN/GaN HEMTs

Kalavagunta

Touboul

Shen

et al. 2008

IEEE Trans. Nucl. Sci.

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Displacement-damage induced degradation in AlGaN/AlN/GaN HEMTs with polarization charge induced 2DEGs is examined using simulations and experiments. Carrier removal in the unintentionally doped AlGaN layer changes the space charge in the structure and this changes the band bending. The band bending decreases the 2DEG density, which in turn reduces the drain current in the device. The effect of the defect energy levels on the 2DEG density is also studied. The interplay between carrier removal, mobility degradation, and the charged defects is analyzed and quantified.

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Section: Deg Density and Defect Location And Energysupporting

confidence: 93%

Section: B Vacancies and Defects In Gan And Alganmentioning

confidence: 99%

Electrostatic Mechanisms Responsible for Device Degradation in Proton Irradiated AlGaN/AlN/GaN HEMTs

Kalavagunta

Touboul

Shen

et al. 2008

IEEE Trans. Nucl. Sci.

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“…Lateral DRCLS obtained from specific depths provides information on composition and defects to account for the variations in HEMT properties. Figures 18(a) and (b) depict the lateral and cross-sections geometries of this application, respectively [101][102][103][104][105][106]. Figure 18(a) shows how DRCL spectra are acquired at increasing radial distances of the wafer.…”

Section: Application To Transistorsmentioning

confidence: 99%

Applications of depth-resolved cathodoluminescence spectroscopy

Brillson¹

2012

J. Phys. D: Appl. Phys.

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Depth-resolved cathodoluminescence spectroscopy (DRCLS) has developed over the past few decades into a powerful technique for characterizing electronic properties of advanced materials structures and devices on a nanoscale. The lateral and depth-resolved capabilities of DRCLS enable researchers to probe native defects, impurities, chemical changes and local band structure inside state-of-the-art device structures on an unprecedented scale. A key strength of DRCLS is its ability to distinguish electronic features at buried interfaces within multilayer device structures, interfaces whose microscopic physical features can determine macroscopic electronic properties. This review provides a general overview of DRCLS and illustrates the wide array of applications now available using this technique.

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“…[8] All of these charges are functions of the gate voltage, and contribute to the transfer characteristics of the FET. In addition all of them are vulnerable to modification by external probes: the heterojunction and the spontaneous polarization are sensitive to changes in the doping distribution caused by field-induced motion of the doping atoms [9], and the piezoelectric charge by relaxation of stress at the interface due to field-induced motion of dislocations [10]. Current transport through an intact barrier is primarily via tunneling, which is sensitive both to the height and the width of the barrier.…”

Section: Discussionmentioning

confidence: 99%

Identification of Pre-Catastrophic Failure Mechanisms in High Power GaN HEMT

Huebschman

Crowne

Darwish

et al. 2011

2011 IEEE Compound Semiconductor Integrated Circuit Symposium (CSICS)

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Extended relibability measurementsThe research describes an investigation into an observed phenomenon believed to be correlated with catastrophic device failure cause by the breakdown in the gate structure in high power, high frequency GaN HEMTs. Several devices that were stressed on an elevated temperature extended reliability test station showed significant changes in gate current prior to catastrophic failure. In an effort to electrically examine the devices during the breakdown process, similar devices were stressed on wafer. Detailed measurements were performed on the devices at regular intervals. On several devices, the behavior of interest was reproduced. Of the periodic measurements performed, a gate current sweep provided the greatest insight into device operation. Explanations for the observed phenomena are discussed.Index Terms -Gallium nitride, HEMT, reliability, gate break down.

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Role of barrier and buffer layer defect states in AlGaN/GaN HEMT structures

Cited by 16 publications

References 12 publications

Electrostatic Mechanisms Responsible for Device Degradation in Proton Irradiated AlGaN/AlN/GaN HEMTs

Electrostatic Mechanisms Responsible for Device Degradation in Proton Irradiated AlGaN/AlN/GaN HEMTs

Applications of depth-resolved cathodoluminescence spectroscopy

Identification of Pre-Catastrophic Failure Mechanisms in High Power GaN HEMT

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