Si Implanted Reactivation in GaN Grown on Sapphire Using AlN and Oxide Cap Layers

Frédéric Cayrel (1) , Anne-Elisabeth Bazin (1, 2) , Mohamed Lamhamdi (1) , Y. Benchanaa , Olivier Ménard (1) , Arnaud Yvon , Emmanuel Collard , Daniel Alquier (1)

1 GREMAN - UMR 7347 - GREMAN (matériaux, microélectronique, acoustique et nanotechnologies)
2 ST-TOURS - STMicroelectronics [Tours]

Gallium nitride (GaN) is a promising material for power electronic devices. Due to GaN sensitivity to high temperature treatments, dopant activation, after ion implant, is one of the major critical steps to be overcome. An annealing cap layer is then mandatory during high temperature treatment to avoid degradations. In this work, cap layers, such as AlN and SiOx, were deposited on Si-implanted N-type GaN. Samples were annealed using both classical (FA) and rapid thermal (RTA) annealing for times ranging from 30 s to 8 h and temperatures from 1000 to 1150 °C. Transmission Electron Microscopy has been done to observe the implanted layer structure. After cap layer removal, samples surface has been investigated through Atomic Force Microscopy measurements. Dopant activity was indirectly evaluated by Specific Contact Resistance (SCR) measurements. This work demonstrates that low SCR value (8.2 Â 10À5 X cm2) with low surface roughness ($1 nm) can be reached using RTA and an oxide cap layer. However, presence of hexagonal pits in GaN layer is difficult to avoid. Compromise between low SCR with low roughness value and low hexagonal pits density on the GaN surface must be found.

Domaines: Micro et nanotechnologies/Microélectronique

Frédéric Cayrel, Anne-Elisabeth Bazin, Mohamed Lamhamdi, Y. Benchanaa, Olivier Ménard, et al.. Si Implanted Reactivation in GaN Grown on Sapphire Using AlN and Oxide Cap Layers. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2012, 272, pp.137-140. ⟨10.1016/j.nimb.2011.01.050⟩. ⟨hal-01810910⟩