Electron Beam Annealing of Phosphorus Implanted Cadmium Telluride

Abstract

ABSTRACTThe behavior of dopants in CdTe has been examined by Krogen and DeNobel and others. The n-type material is easy to dope with good electrical activity. The p-CdTe is more difficult to produce with concentration higher than 6×1016 cm-3. For doping levels above this, the electrical activity of the dopant drops sharply and the hole mobility is reduced. The difficulty in doping p-CdTe stems from both strong compensation effects and low solubility of the usual dopant species.The electron beam pulse method has been applied to annealing phosphorus implanted cadmium telluride. The threshold electron beam energy density necessary to give good electrical activation and mobility have been established in the range between 9.2-10.1 J.cm-2 for doses from 1014-1016 ions cm-2. A sheet resistance as low as 6.32×10 Ω/  and a carrier concentration as high as 3×1018 cm-3 have been obtained. The impurity profile of the annealed samples have been obtained by etching layer by layer with the etching rate calibrated by chemical techniques and the impurity concentration determined by van der Pauw/Hall technique.