Avalanche Effects in Silicon p—n Junctions. II. Structurally Perfect Junctions

Abstract

The fabrication of a planar guard ring diode which exhibits uniform microplasma‐free breakdown is described. Discrepancies are discussed between the behavior of these junctions and those reported by Batdorf et al. and Chynoweth, including results showing extremely hard V‐I characteristics associated with uniform avalanche breakdown. Experimental evidence is presented which confirms Shockley's theory in which the breakdown behavior is predicted from the Poisson distribution of impurities within the space‐charge layer. The photomultiplication technique as described in Paper I is applied to uniform p—n junctions. The linearity of 1/M vs V, as predicted by theory, was verified for values of M between 1.6 and 500. For higher values, the multiplication curves deviate from a straight line. In this higher range they are in good agreement with the pulse‐multiplication model developed in Paper I. Light emission patterns from these junctions are shown and a correlation between these patterns and crystal properties is discussed. The effects of resistivity striations in the siliconsingle crystals is shown to have a strong effect on breakdown areas and no effects of dislocations and oxygen on uniformity are found. From capacity and multiplication measurements a value for the breakdown field of EB =445±25 kV/cm was obtained for a 32‐V junction.