Progress towards a physical contact model for scanning spreading resistance microscopy

As emphasized in the ITRS roadmap, two-dimensional (2D) carrier profiling is one of the key elements in support of technology development. For CMOS silicon devices, scanning spreading resistance microscopy (SSRM) has demonstrated an attractive spatial resolution and concentration sensitivity. The automated construction of calibration curves allows for the fast semi-quantitative transformation of one-dimensional (1D) and 2D resistance profiles/images into resistivity/carrier profiles/images. However in order to arrive, at a reliable, fully quantitative analysis a new physical contact model involving a Schottky-like contact with tunneling and surface states has been proposed. The latter has been based on establishing a qualitative agreement with experimental data. The first aim of this work is to refine this contact model in order to achieve a quantitative agreement between device simulations (with ISE/DESSIS) and experimental 1D profiles on well-calibrated, junction isolated (carrier spilling affected), sub-micron CMOS structures. Among others, scanning spreading resistance spectroscopy (SSRS), i.e. collecting a full I–V curve at each data point, will be used. Furthermore, the impact of this new contact model on the deconvolution procedure from the measured resistance profiles/images towards resistivity/carrier profiles/images through an improved correction factor database will be discussed.