A pathway to highly conducting Ge-doped AlGaN

Ge doping in AlGaN was studied over a wide dopant concentration range. For high Ge concentrations, the formation of VIII–nGeIII was determined to be the main point defect limiting the conductivity. It was shown that the complex formation could be suppressed by controlling chemical potentials during...

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Bibliographic Details
Published inJournal of applied physics Vol. 130; no. 20
Main Authors Bagheri, Pegah, Kim, Ji Hyun, Washiyama, Shun, Reddy, Pramod, Klump, Andrew, Kirste, Ronny, Mita, Seiji, Collazo, Ramón, Sitar, Zlatko
Format Journal Article
LanguageEnglish
Published Melville American Institute of Physics 28.11.2021
Subjects
Applied physics
Carrier density
Chemical potential
Complex formation
Germanium
Point defects
Sapphire
Self compensation
Substrates
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Summary:Ge doping in AlGaN was studied over a wide dopant concentration range. For high Ge concentrations, the formation of VIII–nGeIII was determined to be the main point defect limiting the conductivity. It was shown that the complex formation could be suppressed by controlling chemical potentials during growth, leading to a higher maximum achievable carrier concentration and selective stabilization of a certain complex type. Chemical potential of the growth species was varied by changing the V/III ratio and growth temperature. Free carrier concentrations as high as 4 × 1019 cm−3 were achieved in Al0.4Ga0.6N:Ge grown on sapphire substrates under “metal-rich” conditions. The ability to control the onset of self-compensation and to stabilize a certain charge state of the compensating defect is of great technological importance for application of AlGaN in various devices.
ISSN:0021-8979
1089-7550
DOI:10.1063/5.0071791