Problems related to the avalanche and secondary breakdown of silicon P-N junction

Abstract

The paper provides an analysis of some still unsolved problems related to avalanche and secondary breakdown. An evaluation is given of four models of energy accumulation, necessary for impact ionization: Wolf's diffusion model, Shockley's model of ‘lucky’ electrons, Ridely's model of ‘lucky-drift’ and Gribnikov's model of ‘light’ electrons. It is shown that impact ionization is mainly realized in conformity with the model of ‘light’ charge carriers. It is indicated that the bright avalanche breakdown channels, called microplasmas, are encircled by a weakly shining ring-shaped cloud. Apparently this cloud is caused by the ‘light’ charge carriers. As the p-n junction is heated under the influence of a high avalanche breakdown current and reaches a certain temperature, the luminous clouds expand and by force of the magnetic pinch created by the current itself tend towards the centre, where they meet and assume the form of a ring. Then the weakly shining cloud (pre-mesoplasma) contracts rapidly and bright circular mesoplasma lights up (secondary breakdown appears) which moves in the direction of higher temperature and higher voltage until it localizes at a large defect or contact. A model is proposed according to which pre-mesoplasma and mesoplasma is a flow of ‘light’ charge carriers. This model allows us to explain many peculiarities of pre-mesoplasma and mesoplasma.