Effect of Group-III precursors on unintentional gallium incorporation during epitaxial growth of InAlN layers by metalorganic chemical vapor deposition

Jeomoh Kim, Mi Hee Ji, Theeradetch Detchprohm, Russell D. Dupuis, Alec M. Fischer, Fernando Ponce, Jae Hyun Ryou

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Abstract

Unintentional incorporation of gallium (Ga) in InAlN layers grown with different molar flow rates of Group-III precursors by metalorganic chemical vapor deposition has been experimentally investigated. The Ga mole fraction in the InAl(Ga)N layer was increased significantly with the trimethylindium (TMIn) flow rate, while the trimethylaluminum flow rate controls the Al mole fraction. The evaporation of metallic Ga from the liquid phase eutectic system between the pyrolized In from injected TMIn and pre-deposited metallic Ga was responsible for the Ga auto-incorporation into the InAl(Ga)N layer. The theoretical calculation on the equilibrium vapor pressure of liquid phase Ga and the effective partial pressure of Group-III precursors based on growth parameters used in this study confirms the influence of Group-III precursors on Ga auto-incorporation. More Ga atoms can be evaporated from the liquid phase Ga on the surrounding surfaces in the growth chamber and then significant Ga auto-incorporation can occur due to the high equilibrium vapor pressure of Ga comparable to effective partial pressure of input Group-III precursors during the growth of InAl(Ga)N layer.

Original languageEnglish (US)
Article number125303
JournalJournal of Applied Physics
Volume118
Issue number12
DOIs
StatePublished - Sep 28 2015

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ASJC Scopus subject areas

  • Physics and Astronomy(all)

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