Mapping of crystal defects and the minority carrier diffusion length in 6H–SiC using a novel electron beam induced current technique

Tabib-Azar, Massood; Hubbard, Seth M.; Schnabel, C.M.; Bailey, Sheila G.

doi:10.1063/1.368578

Cited by 17 publications

(10 citation statements)

References 13 publications

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“…Electron-beam-induced current (EBIC) measurement using the planar mapping technique enables quantitative analysis and spatial visualization of recombination centers that reduce the diffusion length of minority carriers in 6H-SiC Schottky diodes [1,2,3]. Such a procedure coupled with synchrotron white-beam x-ray topography (SWBXT), through which closed core screw dislocations may be identified by their stress signature in the crystal lattice [4], gives insight into the effects of these defects on the minority carrier diffusion length.…”

Section: Introductionmentioning

confidence: 99%

Correlation of EBIC and SWBXT Imaged Defects and Epilayer Growth Pits in 6H-SiC Schottky Diodes

Schnabel

Tabib‐Azar

Neudeck

et al. 2000

MSF

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Section: Introductionmentioning

confidence: 99%

Correlation of EBIC and SWBXT Imaged Defects and Epilayer Growth Pits in 6H-SiC Schottky Diodes

Schnabel

Tabib‐Azar

Neudeck

et al. 2000

MSF

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“…Since the minority carrier transport properties play a significant role in the performance of bipolar devices, measurement of properties such as diffusion length and lifetime are essential to understanding and improving device performance. The diffusion length of minority carriers, L, has been mainly been determined with surface photovoltage (SPV) and electron beam induced current (EBIC) measurements [3,4]. Most previous studies on the SPV of GaN have extracted the diffusion lengths of minority carriers, ignoring the effect of reflectivity, R, and incident light flux, Φ, on the photon energy [5,6].…”

mentioning

confidence: 99%

Surface photovoltage spectroscopy of minority carrier diffusion lengths in undoped and Si‐doped GaN epitaxial films

Park

Kopanski

Kang

et al. 2005

phys. stat. sol. (c)

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Undoped-and Si-doped GaN epitaxial films were grown on sapphire substrates by metal-organic chemical vapor deposition. Variable angle spectroscopic ellipsometry (VASE) and surface photovoltage (SPV) spectroscopy were used to determine the minority carrier diffusion lengths in the films. Both the reflectivity (R) and absorption coefficient (α) could be calculated from the VASE measurements. In the SPV spectra at room temperature, a strong transition with a threshold at 3.42 eV was observed in both films, while an exciton-related absorption was observed only in the undoped GaN. The minority carrier diffusion lengths were measured to be about 200 nm for the undoped GaN and about 20 nm for the Si-doped GaN. Moreover, a large divergence in the range of 1/α in the undoped GaN was found and attributed to a high surface barrier energy.Gallium nitride (GaN) and its alloys are promising materials for optoelectronics, high-power electronics, and high-temperature electronics due to their physical and electrical properties [1]. Despite high background electron concentrations in GaN films, GaN-based devices have shown good efficiencies [2]. Since the minority carrier transport properties play a significant role in the performance of bipolar devices, measurement of properties such as diffusion length and lifetime are essential to understanding and improving device performance. The diffusion length of minority carriers, L, has been mainly been determined with surface photovoltage (SPV) and electron beam induced current (EBIC) measurements [3,4]. Most previous studies on the SPV of GaN have extracted the diffusion lengths of minority carriers, ignoring the effect of reflectivity, R, and incident light flux, Φ, on the photon energy [5,6]. In this study, L in n-type GaN films was investigated using both variable angle spectroscopic ellipsometry (VASE) and SPV measurements. Moreover, the reflectivity, R(E), and the incident light flux, Φ(E), as a function of the photon energy were considered in the analysis, in contrast with the previous analyses of GaN.Two GaN films were grown on sapphire substrates by metallorganic chemical vapor deposition. One was unintentionally doped (undoped) with a resulting background electron concentration of 1.5 × 10 17 cm -3 , and the other was Si-doped with an electron concentration of 5.8×10 18 cm -3 . The thickness of both GaN layers was about 1.1 µm. In order to obtain refractive index and extinction coefficient, VASE measurements were performed in the range of approximately 2 eV to 6 eV. The incident light was polarized and the incident angle was fixed at 75 degrees. For the SPV measurements, monochromatic light from a Xe lamp was chopped at a frequency of 320 Hz. The sample stage was grounded and the surface photovoltage was measured at room temperature.

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“…4,5 In this letter, we focus on the analysis of carrier recombination around the dislocation area in the diffused SiC p -n diode.…”

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confidence: 99%

Electron-beam-induced current observed for dislocations in diffused 4H-SiC P–N diodes

Maximenko

Soloviev

Cherednichenko

et al. 2004

Applied Physics Letters

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The electron-beam-induced current (EBIC) method was employed to investigate the electrical activity of dislocations in silicon carbide Schottky and diffused p–n diodes. Dislocations in Schottky diodes appear as dark spots with the EBIC current signal at the dislocations reduced with respect to the background. However, in p–n diodes, the same dislocations exhibited characteristic bright halos, with the EBIC current higher than that of the background. These bright halos were attributed to a nonuniform impurity distribution around dislocations caused by the high-temperature (∼2000 °C) diffusion process.

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Mapping of crystal defects and the minority carrier diffusion length in 6H–SiC using a novel electron beam induced current technique

Cited by 17 publications

References 13 publications

Correlation of EBIC and SWBXT Imaged Defects and Epilayer Growth Pits in 6H-SiC Schottky Diodes

Correlation of EBIC and SWBXT Imaged Defects and Epilayer Growth Pits in 6H-SiC Schottky Diodes

Surface photovoltage spectroscopy of minority carrier diffusion lengths in undoped and Si‐doped GaN epitaxial films

Electron-beam-induced current observed for dislocations in diffused 4H-SiC P–N diodes

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