Assessing the resolution limits of scanning spreading resistance microscopy and scanning capacitance microscopy

Within this paper we present a general study on the resolution limits of scanning spreading resistance microscopy (SSRM) and scanning capacitance microscopy (SCM). The definition of the resolution concept is not straightforward for carrier profiling techniques and has to be divided into three main parameters: the spatial resolution, the dopant gradient resolution and the concentration sensitivity. Dedicated structures were conceived and processed for this analysis. The present study shows that the SSRM technique has a good spatial resolution (better than 3 nm), dopant gradient resolution (a few nm/dec) and concentration sensitivity. This excellent performance of the SSRM technique can probably be explained by the intimate contact between the probe and the sample and by the absence of stray effects. The SCM technique also offers a reasonable spatial resolution but suffers from a lower signal to noise ratio that may affect its practical use.