Activation of Implanted n-Type Dopants in Ge Over the Active Concentration of 1 X 10(20) cm(-3) Using Coimplantation of Sb and P

One of the greatest challenges in fabricating a Ge-channel n-MOSFET is achieving a high n-type dopant activation within the source and drain regions. Conventional approaches to increase the electrically active doping level have been proven to be unsatisfactory, and typically the highest activation of n-type dopants is 4 X 10(19) cm(-3) using phosphorus. This article describes a method to enhance the activation level of n-type dopants in Ge. Coimplantation of phosphorus and antimony leads to dopant activation over 1 X 10(20) cm(-3) at 500 degrees C. The enhancement of n-type dopant activation is attributed to reducing the implantation damage upon annealing due to increase in solid solubility of the dopants. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3257912] All rights reserved.