Microstructural and electroluminescence measurements were carried out on boron-implanted dislocation engineered silicon light emitting diodes co-implanted with the rare earth thulium to provide wavelength tuning in the infra-red. Silicon light emitting diodes operating in the range from 1.1 to 1.35μm were fabricated by co-implantation of boron and thulium into n-type Si (100) wafers and subsequently rapid thermally annealed to activate the implants and to engineer the dislocation loop array that was crucial in allowing light emission. Ohmic contacts were applied to the p and n regions to form conventional p-n junction light emitting diodes. Electroluminescence was obtained under normal forward biasing of the devices. The influence of implantation sequence (B or Tm first), ion dose, and the post-implantation annealing on the microstructure and electroluminescence from the devices was studied. A clear role of the heavy-ion Tm co-implant in significantly modifying the boron induced dislocation loop array distribution was demonstrated. Also identified was the development of dislocation loops under thermal spikes upon heavy ion (Tm) implantation into Si. The results contributed to a better understanding of the basic processes involved in fabrication and functioning of co-implanted devices, towards achieving higher light emission efficiency.

Role of Heavy Ion Co-Implantation and Thermal Spikes on the Development of Dislocation Loops in Nanoengineered Silicon Light Emitting Diodes. M.Milosavljević, M.A.Lourenço, R.M.Gwilliam, K.P.Homewood: Journal of Applied Physics, 2011, 110[3], 033508