electric field to become distorted and the charge to be unevenly distributed permitting the defects to be identified fig6 a is a top view of a silicon wafer 200 fig6 b is a cross section view of a wafer 200 having a substrate 210 and a dielectric layer 201 the positive charge on the dielectric 201 is located at the exterior surface 202 the negative charge on the interior surface of the dielectric is drawn from the cathode 150 through the silver paint in notch 203 and the substrate 210 in the preferred embodiment of step 30 the wafer is first placed inside the ionization chamber 112 and moved to the start position as illustrated in fig7 the wafer is allowed to cool in the presence of nitrogen after being heated in step 20 of fig5 to drive off any water after the wafer 200 has cooled a motor driving the slide is activated and then the high voltage power supply connected to the anode is activated fig8 a d are graphs of the high voltage and time required to depost a charge of a particular voltage on the surface of the dielectric as a function of dielectric thickness in the preferred embodiment charge is deposited on the surface of the dielectric until a potential is developed which is typically from less than one volt per cm 2 for 100 angstrom oxides to greater than 90 volts per cm 2 for 20 000 angstroms 5 and 15 volts cm 2 the resolution of the present invention may be adjusted by.