Extended noise analysis — a novel tool for reliability screening
Noise specifies the fluctuations of device characteristics under operation. Low frequency noise can be used to obtain information on the internal device quality under operating conditions. Commonly, only the noise power spectrum is measured in frequency domain. This is equivalent to the second order moments of the fluctuating quantity. Restriction on reliability prediction via power spectrum analysis means restriction on the second order moments of the fluctuating quantity. Our intention is more general. We are searching for tolerance limits of noise characteristics in time and frequency domain capable of separating reliable devices from non-reliable. Extended noise analysis is a new method of noise characterization in time domain. It considers the 2-dimensional distributions of noise signals at the beginning and the end of a time interval. This yields additional information. Quantities like moments of higher order and the parameters of conditional distributions indicate atypical dynamics. The approach was used to characterize the low frequency current noise of InGaAs/AlGaAs laser diodes at currents well below threshold. Failed and surviving items show different distributions of several noise characteristics.