A technique has been developed to determine the density and distribution of spatially deep traps throughout an insulator. These traps were created and charged by a high voltage stressing pulse and allowed to discharge upon the removal of the pulse. During the transient following pulse removal, the currents were measured. A correlation from current to trap densities and from time of decay to location within the dielectric has been made. This method has been applied to gauge the differences between nitrided dielectrics and thermal oxides. We have found initial trap levels, before stressing, to be lower in silicon oxide devices than silicon oxynitride devices. However, trap levels increased faster in thermal oxides as the stress increased, and became larger than the levels found in nitrided oxides. Nitrided devices tended to resist additional trap formation. Current-voltage measurements have shown that nitrides developed higher leakage currents as the stress was increased than did thermal oxides.