Pendeo-epitaxy of GaN on SOI nano-pillars: Freestanding and relaxed GaN platelets on silicon with a reduced dislocation density

Roy Dagher (1) , Philippe de Mierry (1) , Blandine Alloing (2) , Virginie Brandli (3) , Marc Portail (1) , Benjamin Damilano (1) , Nicolas Mante (4) , Nicolas Bernier (4) , Patrice Gergaud (4) , Maximilien Cottat (5) , Cécile Gourgon (6) , Jesus Zuniga Perez , Guy Feuillet (4)

1 CRHEA - Centre de recherche sur l'hétéroepitaxie et ses applications
2 EPFL - Ecole Polytechnique Fédérale de Lausanne
3 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
4 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information
5 CSPBAT - Chimie, Structures et Propriétés de Biomatériaux et d'Agents Thérapeutiques
6 LTM - Laboratoire des technologies de la microélectronique

Nanopendeo-epitaxy of gallium nitride (GaN) is considered in this study as a way of producing freestanding GaN with reduced strain and threading dislocation density (TDD) for optoelectronic applications. The novelty of this work lies in the use of silicon on insulator (SOI) substrates patterned into nano-pillars down to the buried oxide (BOX). We actually want to benefit from the creeping properties of SiO2 at the growth temperature of GaN for strain relaxation and grain-boundary dislocations reduction. In this paper, we report on the fabrication of 40×40 µm 2 and 300×300 µm 2 freestanding GaN platelets, up to 10 µm-thick, spontaneously separated from the initial pillars. Structural and optical characterizations show that the platelets are crack-free and almost fully relaxed, with a TDD of ∼ 4×10 8 /cm 2. We underline the different benefits of this approach, but most importantly, we believe that it will be the founding-brick for transferable GaN-based devices.

Mots clés: . Defects; Nanostructures; Metalorganic vapor phase epitaxy; Pendeo-Epitaxy; Gallium nitride; Silicon on insulator

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

Roy Dagher, Philippe de Mierry, Blandine Alloing, Virginie Brandli, Marc Portail, et al.. Pendeo-epitaxy of GaN on SOI nano-pillars: Freestanding and relaxed GaN platelets on silicon with a reduced dislocation density. Journal of Crystal Growth, 2019, 526, pp.125235. ⟨10.1016/j.jcrysgro.2019.125235⟩. ⟨hal-02304951⟩