ELECTRICAL HARMONIC-GENERATION FROM NOTCHED NARROW METAL LINES

A model for electrical harmonic generation in metal thin films has bee n developed based on the solution to the thermal diffusion equation us ing a Green's function method and a number of simple assumptions. The validity of the model is demonstrated by measurements of the amplitude of the second and third harmonic signals using uniform aluminum lines on sapphire. By introducing damage in the form of narrow notches of p rescribed size into the aluminum lines, we have been able to calibrate , and compare, the notch sensitivities of the dc resistance and the se cond and third harmonic signals. Predictions based on a simple approxi mate treatment of the notches yields good agreement with damage sensit ivity of both the resistance and harmonic signals. It was found that t he second and the third harmonic signals are equally sensitive to dama ge in the aluminum lines. Furthermore, the harmonic signals are consid erably more sensitive to the presence of damage than is the de resista nce. Also, the effect of a number of distinct damage sites in a line i s shown to be a linear superposition of each for both the harmonic sig nals and the resistance. (C) 1998 American Institute of Physics.