Flash Annealing Technology for USJ: Modeling and Metrology
Millisecond annealing either by flash lamp or laser appears to be the leading approach to meet the needs of ultra-shallow junction annealing and polysilicon activation for advanced technology nodes. There are many advantages to this technology including high electrical activation, excellent lateral abruptness, controlled and limited dopant diffusion and the ability to engineer the extended defects remaining from the ion implantation. There are also many challenges such as potential pattern effects, local and global wafer stress and difficulty in process integration. Additional challenges include the need to extend the capabilities of process TCAD to allow accurate simulation and prediction of the ms processes. Modeling of diffusion, activation and defect evolution for a variety of technologically interesting doping conditions must be dependable to allow the device designer and process engineer to predict the device behavior after ms annealing. Existing models fall short or still need to be validated. Metrology for ultra-shallow junctions is also a challenge. The ability to accurately and repeatably measure sheet resistance and junction leakage on junctions of the order of 10nm deep is very difficult. This paper provides an overview of flash lamp annealing and deal with some promising extensions of process simulation to enable the predictive modeling of junction behavior under flash lamp annealing conditions. We also examine some of the new metrology techniques for characterization of these very shallow junctions and look at some of the trends exhibited for different junction formation details
Analytical Model for Two-Dimensional Ion Implantation Profile in MOS-Structure Substrate
We derived an analytical model to obtain a 2-D impurity concentration profile for ions implanted at high-tilt angles in MOS-structure substrates. This model enabled us to simulate MOS device characteristics with a fully analytical impurity distribution where diffusion was neglected. We tested and verified that our analytical model could provide the same results as the ones obtained using a 2-D process simulator.
Within and Inter-Institutional Differences Between Death Certifiers on Autopsy Conclusions
This study seeks to establish whether medico-legal practitioners differ in their autopsy conclusions within and across medico-legal institutions. Data include 459 violent deaths (homicides, suicides, and accidents) autopsy reports written by more than 20 death certifiers from four medico-legal institutions in two countries (France and the United States). Multinomial models show that compared with accidental deaths, weapon use and decedents’ characteristics both influence a homicide verdict, but not a suicide one. In addition, French practitioners are more likely than Americans to reach a conclusion of homicide or suicide compared with accident, and homicides are more likely to be certified by male practitioners.