In-Situ Rare Earth Doping of Silicon-Based Nanostructures By Plasma Enhanced Chemical Vapour Deposition

In order for Si-based materials to be used in solid-state lighting (SSL) schemes it is necessary to have precise control of the optical emission from these materials. This can be accomplished through the use of rare earth dopants such as Ce, Tb, and Eu to obtain blue, green, and red emissions, respectively. After a brief review of the latest developments in the field, this talk will focus on several in-situ doping approaches to achieving very high, optically active concentrations of the rare earths. The methodologies include electron cyclotron resonance plasma enhanced chemical vapour deposition (ECR-PECVD), inductively coupled plasma (ICP) CVD as low thermal budget processes for film deposition, reactive sputtering, as well as the use of a recently installed Circular High Vacuum Magnetron Sputtering source attached to the ECR-PECVD tool. We will describe the salient features of the deposition systems and correlate important process parameters with the observed luminescence. Finally, we will discuss some of the challenges in developing electrically driven lighting cells suitable for SSL and in particular, for the development of widely tuneable Si-based light sources. This work has been supported by the Natural Sciences and Engineering Research Council (NSERC) under its Discovery Grants Program.