Experimental investigation of interface states and photovoltaic effects on the scanning capacitance microscopy measurement for $p‐n$ junction dopant profiling

Controlled polishing procedures were used to produce both uniformly doped and $p‐n$ junction silicon samples with different interface state densities but identical oxide thicknesses. Using these samples, the effects of interface states on scanning capacitance microscopy (SCM) measurements could be singled out. SCM measurements on the junction samples were performed with and without illumination from the atomic force microscopy laser. Both the interface charges and the illumination were seen to affect the SCM signal near $p‐n$ junctions significantly. SCM $p‐n$ junction dopant profiling can be achieved by avoiding or correctly modeling these two factors in the experiment and in the simulation.