Annealing characteristics of electrically isolated InGaAsP devices

The authors report on the effects of fluorine implants on the sheet resistivity of n-type InGaAsP layers grown lattice matched to InP by metal organic molecular beam epitaxy. Projected range matched fluorine ions are implanted at multiple energies and single MeV energy at room temperature (RT) and 77 K in both cases. Hall and resistivity measurements are carried out for the van der Pauw samples and the evolution of sheet resistivity (R-s) as a function of annealing temperature was studied in both cases. Fluorine multienergy implantation at 77 K produces higher as-implanted resistivity layers of similar to 10(7) Omega/square compared to RT implants. It is further observed that RT and 77 K implants recover to their preimplanted sheet resistivity values as soon as they are annealed at temperatures higher than 500 degrees C. Substrate temperature and collision cascade density due to multiple energy implants are found to play an important role to optimize the isolation process.