Application of Scanning Microwave Microscopy nano-C-V to investigate dopant defect under a poly gate device

Scanning Microwave Impedance Microscopy (sMIM) and SCM are used to investigate an intermittent process failure identified as a N-type ghost defect. Two samples are investigated, a control and the failed device, using standard contact mode dC/dV (scanning capacitance microscopy equivalent) and non-resonant imaging with local C-V sweeps. It is shown that SCM and sMIM dC/dV are not conclusive in identifying the defect; but imaging with localized Capacitance versus Voltage (C-V) curves was able to identify and characterize a dopant defect. The suspected failure was located under a section of the gate. N-type carriers in the failure location were only visible when the system was negatively biased and were not present in an identically prepared control sample that exhibited normal device electrical behavior.