Analysis of tellurium as n-type dopant in GaInP:: Doping, diffusion, memory effect and surfactant properties

The use of tellurium as n-type dopant for GaAs and InP has several advantages, including a high incorporation efficiency, the very high doping levels achievable and a low diffusion coefficient. However, its use to dope GaxIn1-xP is not straightforward, since it shows several problems like a remarkable memory effect and an acute inertia of the material to become Te-doped, which gives rise to gradual doping profiles. In this paper, all these phenomena are studied and quantified using secondary ion mass spectroscopy (SIMS) and electrochemical CV profiling (ECV) measurements. Concerning the gradual doping profiles, their origin is linked to the interaction of Te and In in the gas phase and on the growth surface. A phenomenological explanation is given for this effect although the exact physical processes behind remain to be defined. (c) 2006 Elsevier B.V. All rights reserved.