Investigation of molecular co-doping for low ionization energy p-type centers in GaN

摘要

This work initiates an investigation of molecular co-doping to produce p-type centers in (Ga,Al)N with ionization energies lower than Mg. Dopant complexes can be formed between a doubly ionized acceptor such as (Li or Ag) and a singly ionized donor (silicon). Ion implantation of Li and Ag into silicon doped GaN films grown by Metalorganic Chemical Vapor Deposition (MOCVD) has been performed. High resolution X-ray diffraction was used to characterize the crystalline damage and subsequent recovery upon anneal. A complete recovery was observed after annealing at 850℃. Higher temperature anneal was required to activate the implanted Si dopants and was also performed with the co-doped samples. Conductivity measurements - Hall and Van der Pauw - were employed to analyze the conductivity type of these samples. None of the samples analyzed showed any indication of p-type conductivity.