ON THE REDUCTION OF CARRIER SPILLING EFFECTS DURING RESISTANCE MEASUREMENTS WITH THE SPREADING IMPEDANCE PROBE

Despite the rapidly increasing capabilities of Poisson deconvolution schemes for spreading resistance (SR) measurements, carrier spilling effects will remain a serious problem for the interpretation of SR profiles for structures involving significant forward spilling such as epilayers. In order to remedy this situation a spreading impedance probe is being developed allowing to influence the internal spilling by an external dc field, while performing an impedance measurement at a small ac bias. Three-dimensional calibration surfaces representing resistance versus resistivity and dc bias determine the probe characteristics. Results for a p well and a p . p+ epilayer will be discussed.