Kinetics of Shallow Junction Activation: Physical Mechanisms

Forming highly active shallow junctions is a key component enabling low external resistance and high transistor performance. Millisecond flash or scanning laser anneals can be used to contain diffusion and optimize activation, either directly by leveraging temperatures exceeding 1200C, or in combination with non-equilibrium processes such as amorphization plus solid phase epitaxy or liquid phase epitaxy. Diffusionless profiles can be obtained, but may not be optimal for devices. Consideration of deactivation physics is crucial to incorporation of any process leveraging superactive doping, since relaxation of doping is frequently very rapid, and may be crucially influenced by implant damage effects. Developing an understanding of dominant mechanisms is essential for the exploitation of millisecond or faster anneals to form superactive doping.