Experimental verification of inhomogeneous field distribution in negatively bevelled high-voltage p-n junctions by means of photomultiplication

Laser-beam-excited photocurrent measurements of the space-charge layer width close to the surface of a negatively bevelled diffused p-n junction revealed the existence of a well defined region of carrier multiplication at high applied voltages. The region is located within the space-charge layer on the highly doped side of the junction and close to the surface. The laser-light wavelength was 6328 Å and the beam diameter was about 5 ¿m. The experimental results are consistent with the theoretically predicted existence of a field maximum in this region of negatively bevelled p-n junctions.