Effect of Ge doping on growth stress and conductivity in Al x Ga 1-x N

Anushka Bansal, Ke Wang, James Spencer Lundh, Sukwon Choi, Joan Marie Redwing

Research output: Contribution to journalArticle

Abstract

Silicon (Si) is a common n-type donor in Al x Ga 1-x N; however, it induces bending of edge-type threading dislocations which can generate tensile stress in the film leading to the formation of channeling cracks in thick layers. Germanium (Ge) has previously been investigated as an alternative to Si for n-type doping of GaN, but its impact on film stress in Al x Ga 1-x N has not been investigated in detail. In this study, we employ in situ wafer curvature measurements combined with postgrowth characterization to investigate Ge doping of Al x Ga 1-x N (x = 0-0.62) layers grown on 6H-SiC by metalorganic chemical vapor deposition. It was found that Ge doping (n ∼ 1.6 × 10 19 cm −3 ) of Al 0.30 Ga 0.70 N does not induce tensile stress during growth in contrast to that observed with a similar level of Si doping. In addition, the average inclination angle of edge dislocations was similar for undoped and Ge doped films indicating that Ge does not promote surface-mediated dislocation climb. High n-type doping was achieved in Ge doped Al x Ga 1-x N for lower Al fraction range (x < 0.5), but resistivity increased and carrier density decreased significantly for higher Al fractions. The results demonstrate Ge doping as a viable alternative to Si doping of Al x Ga 1-x N (x < 0.5) for achieving thick, crack-free layers.

Original languageEnglish (US)
Article number142101
JournalApplied Physics Letters
Volume114
Issue number14
DOIs
StatePublished - Apr 8 2019

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germanium
conductivity
silicon
tensile stress
cracks
edge dislocations
inclination
metalorganic chemical vapor deposition
curvature
wafers
electrical resistivity

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

Cite this

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title = "Effect of Ge doping on growth stress and conductivity in Al x Ga 1-x N",
abstract = "Silicon (Si) is a common n-type donor in Al x Ga 1-x N; however, it induces bending of edge-type threading dislocations which can generate tensile stress in the film leading to the formation of channeling cracks in thick layers. Germanium (Ge) has previously been investigated as an alternative to Si for n-type doping of GaN, but its impact on film stress in Al x Ga 1-x N has not been investigated in detail. In this study, we employ in situ wafer curvature measurements combined with postgrowth characterization to investigate Ge doping of Al x Ga 1-x N (x = 0-0.62) layers grown on 6H-SiC by metalorganic chemical vapor deposition. It was found that Ge doping (n ∼ 1.6 × 10 19 cm −3 ) of Al 0.30 Ga 0.70 N does not induce tensile stress during growth in contrast to that observed with a similar level of Si doping. In addition, the average inclination angle of edge dislocations was similar for undoped and Ge doped films indicating that Ge does not promote surface-mediated dislocation climb. High n-type doping was achieved in Ge doped Al x Ga 1-x N for lower Al fraction range (x < 0.5), but resistivity increased and carrier density decreased significantly for higher Al fractions. The results demonstrate Ge doping as a viable alternative to Si doping of Al x Ga 1-x N (x < 0.5) for achieving thick, crack-free layers.",
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Effect of Ge doping on growth stress and conductivity in Al x Ga 1-x N . / Bansal, Anushka; Wang, Ke; Lundh, James Spencer; Choi, Sukwon; Redwing, Joan Marie.

In: Applied Physics Letters, Vol. 114, No. 14, 142101, 08.04.2019.

Research output: Contribution to journalArticle

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T1 - Effect of Ge doping on growth stress and conductivity in Al x Ga 1-x N

AU - Bansal, Anushka

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AU - Lundh, James Spencer

AU - Choi, Sukwon

AU - Redwing, Joan Marie

PY - 2019/4/8

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