Flash Annealing Technology for USJ: Modeling and Metrology

Millisecond annealing either by flash lamp or laser appears to be the leading ap proach to meet the needs of ultra-shallow junction annealing and polysilicon act ivation for advanced technology nodes. There are many advantages to this technol ogy including high electrical activation, excellent lateral abruptness, controll ed and limited dopant diffusion and the ability to engineer the extended defects remaining from the ion implantation. There are also many challenges such as pot ential pattern effects, local and global wafer stress and difficulty in process integration. Additional challenges include the need to extend the capabilities o f process TCAD to allow accurate simulation and prediction of the ms processes. Modeling of diffusion, activation and defect evolution for a variety of technolo gically interesting doping conditions must be dependable to allow the device des igner and process engineer to predict the device behavior after ms annealing. Ex isting models fall short or still need to be validated. Metrology for ultra-shal low junctions is also a challenge. The ability to accurately and repeatably meas ure sheet resistance and junction leakage on junctions of the order of 10nm deep is very difficult. This paper will provide an overview of flash lamp anneali ng and deal with some promising extensions of process simulation to enable the p redictive modeling of junction behavior under flash lamp annealing conditions. W e will also examine some of the new metrology techniques for characterization of these very shallow junctions and look at some of the trends exhibited for diffe rent junction formation details.