SPATIAL SYMMETRY OF TRANSDUCTION EFFECTS IN HALL PLATES

In this paper, the separation of transduction effects on the basis of their spatial symmetry relations is presented. The current flow through a symmetrical device is made to spin in a stepwise manner. The output signal as a function of the spatial orientation is sampled and Fourier transformed. A 'spatial' frequency spectrum results, in which each distinct spatial symmetry relation is represented by a different Fourier coefficient. A finite-element model of the piezoresistive effect in the Laplace equation is used to verify the experimental results. In the symmetrical 16-contact Hall plate. the Hall effect is present in the a0 coefficient and the pi-periodic stress in the c2 coefficient in (100) oriented silicon. Geometric lithographic errors contribute to both c2 and c6.