Three-dimensional measurement of Mg dopant distribution and electrical activity in GaN by correlative atom probe tomography and off-axis electron holography

Lynda Amichi (1) , Isabelle Mouton (2) , Enrico Di Russo (2) , Victor Boureau (2) , Frédéric Barbier (2) , Amélie Dussaigne (2) , Adeline Grenier (2) , Pierre-Henri Jouneau (1) , Catherine Bougerol (3) , David Cooper (2)

1 IRIG - Institut de Recherche Interdisciplinaire de Grenoble
2 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information
3 NEEL - NPSC - Nanophysique et Semiconducteurs

The distribution and electrical activity of p-type doping (Mg) in gallium nitride (GaN) grown by metal organic chemical vapor deposition was investigated by correlating atom probe tomography (APT) and off-axis electron holography. APT results revealed that high Mg concentrations promote the formation of Mg-rich clusters. This is associated with the formation of pyramidal inversion domains (PIDs). The direct measurement of the doping concentration outside the clusters provided by APT suggests a saturation in the p-type electrical activity for Mg concentrations above 7 x 10 19 cm-3. Maps of the electrostatic potential provided by off-axis electron holography confirm that the highest carrier concentration was achieved in the regions with the highest dopant concentration of 2 x 10 20 cm-3 , despite the presence of a high density of Mg-rich clusters revealed by APT. The correlation of these techniques suggests that PIDs are not the major cause of the reduction in electrostatic potential.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Lynda Amichi, Isabelle Mouton, Enrico Di Russo, Victor Boureau, Frédéric Barbier, et al.. Three-dimensional measurement of Mg dopant distribution and electrical activity in GaN by correlative atom probe tomography and off-axis electron holography. Journal of Applied Physics, 2020, 127 (6), pp.065702. ⟨10.1063/1.5125188⟩. ⟨hal-02991526⟩