NEW METHOD FOR THE DETERMINATION OF CARRIER LIFETIME IN DIODES USING A SINUSOIDAL CURRENT PULSE

The paper presents a new method for the determination of the carrier c oncentration and the carrier lifetime inside the base of p-n and p-i-n diodes using a sinusoidal current pulse. This pulse is obtained when a sinusoidal voltage signal is applied to a diode in series with a res istance. The carrier lifetime, tau, is determined by measuring the tra nsition time at which the p-n junction becomes reverse biased, after b eing forward biased, as a result of the applied pulse. Solving the dif fusion equation with the boundary conditions for the current at both s ides of the base, an equation is found that relates the carrier lifeti me with the transition time for a given basewidth of the diode and fre quency of the external signal. An expression for the calculation of th e carrier distribution inside the base as a function of the same param eters is also obtained. (C) 1998 Elsevier Science Ltd. All rights rese rved.