The development of the method of measuring thin film conductance

The possibility of measuring the surface conductance of thin films has been shown by using shear –horizontal plate acoustic wave of zero order (SH0), which propagates in the delay line based on the plate of Y –X lithium niobate. This delay line including two interdigital transducers (IDT) was connected to meter of S – parameters E5071C, which allowed to measure the insertion loss and phase of output signal. It has been found that the dielectric plate with thin conducting layer placed above the delay line between IDTs leads to the change the insertion loss and phase of output signal. At that the degree of this change decreases with increasing the width of the gap between delay line and plate. As conducting thin films of chromium and aluminum were used. The conductance of these films changed in the range 1 – 10-6 S and was determined with the help of four-probe method. The experimental data allowed to build the calibration dependence of the shift of output signal phase on surface conductance of films for the fixed width of gap between the plate and delay line (~ 100 microns). This calibration curve turned out close to linear dependence with the slope of 120 degree/S. The developed method may be used for measuring the conductance of such films, the contacts for which cannot be made or these contacts may significantly act on the result of the measurement.