Two-dimensional delineation of semiconductor doping by scanning resistance microscopy

A new technique for the two-dimensional delineation of P–N junctions is presented using a scanning resistance microscope (SRM). The SRM uses a conducting probe to perform localized resistance measurements over a surface. These resistance measurements are used to delineate between regions of different doping type and concentration. Theoretical simulation shows that the SRM is able to delineate between p-type and n-type regions of a surface, and between regions of high and low dopant concentration. By using contact forces of 10−4 N, the contact area is estimated to be 30 nm. Experiments have shown that this technique can localize a P–N junction with a lateral spacial resolution of less than 35 nm, over dopant concentrations ranging from 1015 to 1020 atoms/cm3. In addition, during resistance measurements the SRM is capable of performing simultaneous surface topography measurements.