Low-voltage cross-sectional EBIC for characterisation of GaN-based light emitting devices

Grigore Moldovan, Payani Kazemian, Paul R. Edwards, Vincent K. S. Ong, Oka Kurniawan, Colin J. Humphreys

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Electron beam induced current (EBIC) characterisation can provide detailed information on the influence of crystalline defects on the diffusion and recombination of minority carriers in semiconductors. New developments are required for GaN light emitting devices, which need a cross-sectional approach to provide access to their complex multi-layered structures. A sample preparation approach based on low-voltage Ar ion milling is proposed here and shown to produce a flat cross-section with very limited surface recombination, which enables low-voltage high resolution EBIC characterisation. Dark defects are observed in EBIC images and correlation with cathodoluminescence images identify them as threading dislocations. Emphasis is placed on one-dimensional quantification which is used to show that junction delineation with very good spatial resolution can be achieved, revealing significant roughening of this GaN p-n junction. Furthermore, longer minority carrier diffusion lengths along the c-axis are found at dislocation sites, in both p-GaN and the multi-quantum well (MQW) region. This is attributed to gettering of point defects at threading dislocations in p-GaN and higher escape rate from quantum wells at dislocation sites in the MQW region, respectively. These developments show considerable promise for the use of low-voltage cross-sectional EBIC in the characterisation of point and extended defects in GaN-based devices and it is suggested that this technique will be particularly useful for degradation analysis. (c) 2006 Elsevier B.V. All rights reserved.

LanguageEnglish
Pages382-389
Number of pages8
JournalUltramicroscopy
Volume107
Issue number4-5
DOIs
Publication statusPublished - May 2007

Fingerprint

Induced currents
low voltage
Electron beams
electron beams
Semiconductor quantum wells
quantum wells
Electric potential
minority carriers
point defects
Defects
defects
Cathodoluminescence
delineation
Point defects
diffusion length
cathodoluminescence
p-n junctions
Dislocations (crystals)
escape
spatial resolution

Keywords

  • EBIC
  • GaN
  • diffusion
  • dislocations
  • surface recombination velocity
  • beam-induced-current
  • diffusion length
  • line scan

Cite this

Moldovan, Grigore ; Kazemian, Payani ; Edwards, Paul R. ; Ong, Vincent K. S. ; Kurniawan, Oka ; Humphreys, Colin J. / Low-voltage cross-sectional EBIC for characterisation of GaN-based light emitting devices. In: Ultramicroscopy. 2007 ; Vol. 107, No. 4-5. pp. 382-389.
@article{f19422d2234a4a52b8e7afb472c0fcf1,
title = "Low-voltage cross-sectional EBIC for characterisation of GaN-based light emitting devices",
abstract = "Electron beam induced current (EBIC) characterisation can provide detailed information on the influence of crystalline defects on the diffusion and recombination of minority carriers in semiconductors. New developments are required for GaN light emitting devices, which need a cross-sectional approach to provide access to their complex multi-layered structures. A sample preparation approach based on low-voltage Ar ion milling is proposed here and shown to produce a flat cross-section with very limited surface recombination, which enables low-voltage high resolution EBIC characterisation. Dark defects are observed in EBIC images and correlation with cathodoluminescence images identify them as threading dislocations. Emphasis is placed on one-dimensional quantification which is used to show that junction delineation with very good spatial resolution can be achieved, revealing significant roughening of this GaN p-n junction. Furthermore, longer minority carrier diffusion lengths along the c-axis are found at dislocation sites, in both p-GaN and the multi-quantum well (MQW) region. This is attributed to gettering of point defects at threading dislocations in p-GaN and higher escape rate from quantum wells at dislocation sites in the MQW region, respectively. These developments show considerable promise for the use of low-voltage cross-sectional EBIC in the characterisation of point and extended defects in GaN-based devices and it is suggested that this technique will be particularly useful for degradation analysis. (c) 2006 Elsevier B.V. All rights reserved.",
keywords = "EBIC, GaN, diffusion, dislocations, surface recombination velocity, beam-induced-current, diffusion length, line scan",
author = "Grigore Moldovan and Payani Kazemian and Edwards, {Paul R.} and Ong, {Vincent K. S.} and Oka Kurniawan and Humphreys, {Colin J.}",
year = "2007",
month = "5",
doi = "10.1016/j.ultramic.2006.10.002",
language = "English",
volume = "107",
pages = "382--389",
journal = "Ultramicroscopy",
issn = "0304-3991",
number = "4-5",

}

Low-voltage cross-sectional EBIC for characterisation of GaN-based light emitting devices. / Moldovan, Grigore; Kazemian, Payani; Edwards, Paul R.; Ong, Vincent K. S.; Kurniawan, Oka; Humphreys, Colin J.

In: Ultramicroscopy, Vol. 107, No. 4-5, 05.2007, p. 382-389.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Low-voltage cross-sectional EBIC for characterisation of GaN-based light emitting devices

AU - Moldovan, Grigore

AU - Kazemian, Payani

AU - Edwards, Paul R.

AU - Ong, Vincent K. S.

AU - Kurniawan, Oka

AU - Humphreys, Colin J.

PY - 2007/5

Y1 - 2007/5

N2 - Electron beam induced current (EBIC) characterisation can provide detailed information on the influence of crystalline defects on the diffusion and recombination of minority carriers in semiconductors. New developments are required for GaN light emitting devices, which need a cross-sectional approach to provide access to their complex multi-layered structures. A sample preparation approach based on low-voltage Ar ion milling is proposed here and shown to produce a flat cross-section with very limited surface recombination, which enables low-voltage high resolution EBIC characterisation. Dark defects are observed in EBIC images and correlation with cathodoluminescence images identify them as threading dislocations. Emphasis is placed on one-dimensional quantification which is used to show that junction delineation with very good spatial resolution can be achieved, revealing significant roughening of this GaN p-n junction. Furthermore, longer minority carrier diffusion lengths along the c-axis are found at dislocation sites, in both p-GaN and the multi-quantum well (MQW) region. This is attributed to gettering of point defects at threading dislocations in p-GaN and higher escape rate from quantum wells at dislocation sites in the MQW region, respectively. These developments show considerable promise for the use of low-voltage cross-sectional EBIC in the characterisation of point and extended defects in GaN-based devices and it is suggested that this technique will be particularly useful for degradation analysis. (c) 2006 Elsevier B.V. All rights reserved.

AB - Electron beam induced current (EBIC) characterisation can provide detailed information on the influence of crystalline defects on the diffusion and recombination of minority carriers in semiconductors. New developments are required for GaN light emitting devices, which need a cross-sectional approach to provide access to their complex multi-layered structures. A sample preparation approach based on low-voltage Ar ion milling is proposed here and shown to produce a flat cross-section with very limited surface recombination, which enables low-voltage high resolution EBIC characterisation. Dark defects are observed in EBIC images and correlation with cathodoluminescence images identify them as threading dislocations. Emphasis is placed on one-dimensional quantification which is used to show that junction delineation with very good spatial resolution can be achieved, revealing significant roughening of this GaN p-n junction. Furthermore, longer minority carrier diffusion lengths along the c-axis are found at dislocation sites, in both p-GaN and the multi-quantum well (MQW) region. This is attributed to gettering of point defects at threading dislocations in p-GaN and higher escape rate from quantum wells at dislocation sites in the MQW region, respectively. These developments show considerable promise for the use of low-voltage cross-sectional EBIC in the characterisation of point and extended defects in GaN-based devices and it is suggested that this technique will be particularly useful for degradation analysis. (c) 2006 Elsevier B.V. All rights reserved.

KW - EBIC

KW - GaN

KW - diffusion

KW - dislocations

KW - surface recombination velocity

KW - beam-induced-current

KW - diffusion length

KW - line scan

U2 - 10.1016/j.ultramic.2006.10.002

DO - 10.1016/j.ultramic.2006.10.002

M3 - Article

VL - 107

SP - 382

EP - 389

JO - Ultramicroscopy

T2 - Ultramicroscopy

JF - Ultramicroscopy

SN - 0304-3991

IS - 4-5

ER -