Systematic oxygen impurity reduction in smooth N-polar GaN by chemical potential control

Dennis Szymanski, Ke Wang, Felix Kaess, Ronny Kirste, Seiji Mita, Pramod Reddy, Zlatko Sitar, Ramon Collazo

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Process chemical potential control and dislocation reduction were implemented to control oxygen concentration in N-polar GaN layers grown on sapphire substrates via metal organic chemical vapor deposition (MOCVD). As process supersaturation was changed from ∼30 to 3400, the formation energy of the oxygen point defect increased, which resulted in a 25-fold decrease in oxygen incorporation. Reducing dislocations by approximately a factor of 4 (to ∼109 cm-3) allowed for further reduction of oxygen incorporation to the low-1017 cm-3 range. Smooth N-polar GaN layers with low oxygen content were achieved by a two-step process, whereas first a 1 µm thick smooth N-polar layer with high oxygen concentration was grown, followed by low oxygen concentration layer grown at high supersaturation.

Original languageEnglish (US)
Article number015005
JournalSemiconductor Science and Technology
Issue number1
StatePublished - Jan 2022

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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