Joseph Kopanski, Jay F. Marchiando, Brian G. Rennex, David S. Simons, R P. Chaudhury
SCM images, and the two-dimensional (2-D) dopant profiles extracted from them, show poor reproducibility from laboratory to laboratory. Major factors contributing to SCM image variability include: poor sample surface and oxide quality, excess carrier generation from stray light, reduced sensor dynamic range from stray capacitance, and use of non-optimal SCM operating voltages. This paper discusses the sources of SCM image variability, how they affect the measured SCM images, and possible approaches for mitigating their effects. Best procedures for extracting quantitative 2-D dopant profiles from SCM images using the NIST FASTC2D software are discussed. Finally, a new set of informal research materials consisting of a CMOS transistor pair, an identical pair without metallization, and a pair of transistor-like structures with the type of the source/drains reversed is introduced. These structures are intended for use with the FASTC2D software to help improve laboratory-to-laboratory dopant profile reproducibility.