RE Implantation and Annealing of III-Nitrides

Abstract

Ion implantation is a convenient method to introduce Rare Earth (RE) ions into a host matrix in a controlled manner with a reproducible profile; it also allows lateral patterning for selective area doping. However, a major drawback of the technique is the lattice damage inevitably caused by energetic heavy ions as they penetrate a crystalline host. The crystalline quality is usually recovered, at least partially, by post-implant thermal annealing of samples at high temperatures; recovery of implantation damage in GaN correlates with the activation of electrical, optical or magnetic dopants. In this chapter we first review the structural aspects of ion implantation damage in GaN; we then focus on the damage accumulation during implantation and on the optical activation of RE ions. The influence of the major implantation parameters, fluence, energy, temperature, and geometry, on structural and optical properties of RE-implanted GaN is discussed. Post-implant annealing of GaN at high temperatures requires special measures to protect the surface from nitrogen loss during the treatment. The efficacy of different annealing procedures, including AlN-capping and applying ultra-high nitrogen pressures, are critically assessed. Finally, investigations of RE implantation of the less-studied binary AlN and AlN-containing alloys, AlGaN and AlInN, are briefly reviewed.