MODIFICATION OF VAN DER ZIEL RELATION FOR SPECTRUM OF NOISE IN p–n JUNCTION

Abstract

Spectrum SiD of the white current noise iD(t) in p–n junction with the ideality factor η of the current–voltage characteristic, which is greater than one, is investigated here. It is shown, that the Van der Ziel relation, SiD = 2q(ID + 2Is), intended for η = 1, is inapplicable if η > 1; here q is the elementary charge, ID is the current through the junction, and Is is the saturation current. As the first step, the simplest case is considered, η = 2. That is the main recombination of injected electrons and holes takes place in the middle of the junction depleted region. Such junction may be modeled by two identical junctions with η = 1, which are connected in series. The current noise iD(t) is determined by noise sources of both junctions. Obtained result is generalized by the use of the Gupta theorem for the thermal noise spectrum in nonlinear resistive systems. The current noise spectrum is found, SiD = (2q/η) · (ID + 2Is). This result is the modification of the Van der Ziel relation extended to η ≥ 1. Experimental proof of the modified relation is made by analysis of the white noise spectrum in Schottky diode with δ-doping (having η = 2.2) in the vicinity of thermodynamical equilibrium.