Process Simulation of Dopant Activation by Laser Annealing (I)

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 is developing process models for laser annealing and dopant activation, in order to reduce the impact of series resistance on device performance. Experiments of dopant activation by laser annealing were performed in this year for the project. Silicon-on-insulator (SOI) wafers were used to mimic the device structures of FinFETs or three-dimensional memory devices because the silicon layer is surrounded by oxide. The SOI wafers were implanted with dopants and annealed at high temperatures to obtain uniform doping profiles. Samples were analyzed by Hall measurement to understand the equilibrium active concentrations. Then laser annealing was performed to further improve dopant activation. Some samples received ion implantation for amorphization. The amorphized samples were annealed to produce solid phase or liquid phase epitaxial regrowth. This resulted in non-equilibrium dopant activation. A combination of amorphization and excimer laser annealing (ELA) greatly enhanced phosphorus activation. However, heavy doping with phosphorus reduced the thickness of the amorphous layer. Furnace annealing at 350 °C following ELA induced significant deactivation and the deactivation behavior was similar to that following rapid thermal annealing (RTA).

Project ID:PB10308-2723
External Project ID:MOST103-2221-E182-065