Development of a metal patterned cantilever for scanning capacitance microscopy and its application to the observation of semiconductor devices

Abstract

The performance of scanning capacitance microscopy (SCM) strongly depends on the probe used. We have developed an original probe suitable for SCM (SCM probe), which uses a pyramid-shaped metal tip and metal lead line patterned on a silicon nitride cantilever. We installed the SCM probe on a SCM based on a commercial atomic force microscope (AFM). Differences in silicon oxide thickness and differences of dopant types and densities in a silicon substrate with a thermal oxide layer were successfully imaged by SCM simultaneously with AFM using the SCM probe. Boundaries between different dopant types and densities, which were not recognizable by AFM, were clearly observed by SCM. Signal-to-noise ratio and reproducibility were improved in the SCM images obtained with the SCM probe when compared with images obtained with a metal-coated silicon nitride cantilever.