Multi-microscopy nanoscale characterization of the doping profile in a hybrid Mg/Ge-doped tunnel junction.

E Di Russo (1) , A Mavel , V Fan Arcara , B Damilano , Ioanna Dimkou , S Vézian , A Grenier , M Veillerot , N Rochat , G Feuillet , B Bonef , L Rigutti , J-y Duboz (2) , E Monroy , D Cooper

1 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information
2 CRHEA - Centre de recherche sur l'hétéroepitaxie et ses applications

A multi-microscopy investigation of a GaN tunnel junction (TJ) grown on an InGaN-based light emitting diode (LED) has been performed. The TJ consists of a heavily Ge-doped n-type GaN layer grown by ammonia-based molecular-beam epitaxy on a heavily Mg-doped p-type GaN thin layer, grown by metalorganic vapor phase epitaxy. A correlation of atom probe tomography, electron holography and secondary ion mass spectrometry has been performed in order to investigate the nm-scale distribution of both Mg and Ge at the TJ. Experimental results reveal that Mg segregates at the TJ interface, and diffuses into the Ge-doped layer. As a result, the dopant concentration and distribution differ significantly from the nominal values. Despite this, electron holography reveals a TJ depletion width of ~7 nm, in agreement with band diagram simulations using the experimentally determined dopant distribution.

Mots clés: atom probe tomography; electron holography; tunnel junction; Mg-doping; Ge-doping; LED; atom probe tomography

Domaines: Physique [physics]

E Di Russo, A Mavel, V Fan Arcara, B Damilano, Ioanna Dimkou, et al.. Multi-microscopy nanoscale characterization of the doping profile in a hybrid Mg/Ge-doped tunnel junction.. Nanotechnology, 2020, 31 (46), pp.465706. ⟨10.1088/1361-6528/ab996c⟩. ⟨hal-03411352⟩