Study on avalanche breakdown and Poole–Frenkel emission in Al-rich AlGaN grown on single crystal AlN
Pramod Reddy, Dolar Khachariya, Will Mecouch, M. Hayden Breckenridge, Pegah Bagheri, Yan Guan, Ji Hyun Kim, Spyridon Pavlidis, Ronny Kirste, Seiji Mita, E. Kohn, Ramón Collazo, Zlatko Sitar
Abstract
We demonstrate that theoretical breakdown fields can be realized in practically dislocation free Al-rich AlGaN p-n junctions grown on AlN single crystal substrates. Furthermore, we also demonstrate a leakage current density in AlGaN that is independent of the device area, indicating a bulk leakage phenomenon and not surface or mesa-edge related. Accordingly, we identified the Poole–Frenkel emission from two types of point-defect traps in AlGaN as the primary source of reverse leakage before breakdown. Mg-doped AlGaN exhibited leakage currents due to a shallow trap at ∼0.16 eV in contrast with leakage currents observed in Si-doped AlGaN due to a deep trap at ∼1.8 eV.