Methods for controlling dopant concentration and activation in semiconductor structures

A method for controlling dopant diffusion during annealing, said method comprising the steps of:

• providing a semiconductor having an exposed surface;
• selecting a desired surface abundance of diffusion control groups on said exposed surface from the range of about 5×1013 molecules cm−2 to about 2×1015 molecules cm−2 or from the range of about 0.1 monolayer to about 3 monolayers, wherein said surface abundance of said diffusion control groups is selected so as to control the loss rate of bulk interstitial semiconductor atoms to the exposed surface to achieve a desired rate of diffusion of dopants during annealing;
• treating said exposed surface of said semiconductor with a surface modifying agent, wherein interaction between said surface modifying agent and said semiconductor forms said diffusion control groups on the exposed surface;
• terminating said treating said exposed surface of said semiconductor with said surface modifying agent when said desired surface abundance of diffusion control groups on said exposed surface is reached;
• implanting the semiconductor with a dopant thereby generating a semiconductor having implanted dopant;
• and
• annealing the semiconductor having implanted dopant and said desired surface abundance of diffusion control groups, thereby controlling the rate of diffusion of the dopants during annealing;
• and wherein said step of implanting the semiconductor with dopants is performed prior to said step of treating the exposed surface of the semiconductor with the surface modifying agent;
• and wherein said step of treating the exposed surface of said semiconductor with the surface modifying agent is performed prior to said step of annealing said semiconductor having implanted dopant.