Process Simulation of Dopant Activation by Laser Annealing(II)

Series resistance of sources and drains significantly degrades the performance of integrated circuits, especially for non-planar transistors such as FinFETs, nanowire transistors and three-dimensional memory devices. This project will develop process models for laser annealing and dopant activation. These models will be used for process optimization, in order to reduce series resistance. In previous year, silicon-on-insulator (SOI) wafers were used and phosphorus activation was greatly improved using laser annealing. In this year, the project will develop phosphorus activation model using the highly activated samples prepared by laser annealing. Because dopant activation is limited by the interactions between dopants, dopant activation models basically describe dopant interactions. Therefore, interactions between dopants in laser annealed samples will be induced using annealing at low temperatures. These interactions would cause dopant deactivation, which can be analyzed by Hall measurement for elucidating dopant interaction mechanisms. In addition, the distance between dopants and neighboring dopants was analyzed using Monte-Carlo method to develop dopant reaction models. An analytical model for neighboring dopants would also be developed based on Poisson distribution. Thus the statistical analysis results using Monte-Carlo method can be extended to low-doping conditions. According to the models for neighboring dopants, we can analyze the experimental phosphorus deactivation data and identify the interaction mechanisms for phosphorus. Reaction equations for dopant interactions will be derived. Then heat transfer simulation was performed for laser annealing to obtain temperatures at different locations. The calculated temperature will be used to determine the reaction constants in dopant deactivation equations. The dopant activation level with laser annealing can be simulated. A process simulation platform for dopant activation by laser annealing was therefore established.

Project ID:PB10408-5756
External Project ID:MOST104-2221-E182-039