Self-compensation in heavily Ge doped AlGaN: A comparison to Si doping
Abstract
Self-compensation in Ge- and Si-doped Al0.3Ga0.7N has been investigated in terms of the formation of III vacancy and donor-vacancy complexes. Both Ge- and Si-doped AlGaN layers showed a compensation knee behavior with impurity compensation (low doping regime), compensation plateau (medium doping regime), and self-compensation (high doping regime). A maximum free carrier concentration of 4–5 × 1019 cm−3 was obtained by Ge doping, whereas Si doping resulted in only half of that value, ∼2 × 1019 cm−3. A DFT calculation with the grand canonical thermodynamics model was developed to support the hypothesis that the difference in self-compensation arises from the difference in the formation energies of the VIII-n•donor complexes relative to their onsite configurations. The model suggested that the VIII-2•donor and VIII-3•donor complexes were responsible for self-compensation for both Ge- and Si-doped AlGaN. However, a lower free carrier concentration in Si-doped samples was due to a high VIII-3•Si concentration, resulting from a lower energy of formation of VIII-3•Si.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 25, 2021
- Source ID
- 10.1063/5.0035957
Entities
People
- Andrew Klump
- Douglas L Irving
- Ji-Hyun Kim
- Jonathon N. Baker
- Kelsey J. Mirrielees
- M. Hayden Breckenridge
- Pegah Bagheri
- Pramod Reddy
- Qiang Guo
- Ramón Collazo
- Ronny Kirste
- Seiji Mita
- Shun Washiyama
- Yan Guan
- Zlatko Sitar
Organizations
- Air Force Office of Scientific Research
- Army Research Office
- National Science Foundation
- North Carolina State University
- United States Department of Energy