Influence of 3C–SiC/Si (111) template properties on the strain relaxation in thick GaN films


3C–SiC films were grown by CVD on silicon (111) as templates for GaN.
The template off-cut, thickness and roughness influence the strain in GaN films.
Noticeable stress mitigation and crystal quality enhancement obtained in GaN on 3C–SiC templates.
5 µm thick continuous GaN film grown crack-free by MBE on a 3C–SiC/Si template.
4 µm thick continuous GaN film grown crack-free by MOCVD on a 3C–SiC/Si template.


In this work, we study the influence of 3C–SiC/Si (111) template parameters (thickness, roughness and substrate miscut) on the GaN crystal quality and its strain state. For this, structures with an AlN nucleation layer and 1–4 µm thick GaN layer have been grown by molecular beam epitaxy in order to select the best templates for the growth of thick GaN structures. Similar GaN structures have been grown directly on silicon for comparisons. The influence of the high silicon doping is confirmed on the enhancement of strain relaxation. Despite this limitation, a 5 µm thick crack-free continuous GaN structure (with 1 µm silicon doped) has been successfully grown on the best selected template. Furthermore, the growth by metal–organic chemical vapor deposition of structures with AlN and SiN inter-layers and thick continuous GaN layers on Si (111), 3C–SiC/Si (111) and SoPSiC (silicon on polycrystalline silicon carbide) has been achieved in order to show the relative benefit of each approach in terms of layer quality and strain state.


  • A1. Molecular beam epitaxy
  • A2. Metal–organic vapor phase epitaxy
  • B1. GaN on silicon
  • B2. Cubic silicon carbide,

No comments: