Minority carrier lifetime measurement based on Low frequency fluctuation

Abstract

We present a novel, simple, and accurate approach based on Low frequency voltage fluctuations to determine the averaged carrier lifetime in semiconductor materials and devices. This technique serves to address the limitations faced by existing techniques that use light as the excitation source for lifetime measurement. In this paper, the minority carrier lifetime is inferred from the 1/f Low frequency noise profile exhibited by the device during Low current operation. The current dependence of the power spectral density and its relation to minority carrier lifetime is modeled and derived directly giving a current dependent carrier lifetime. This technique is solely based on the electrical noise and no light source is required for excitation. The Low frequency noise can be easily acquired without significant distortion via a signal analyzer as long as there is a sufficiently good Ohmic contact between the probe and the device under test, and that the device is sufficiently shielded from the influence of EMI. This technique has Lower crosstalk, fewer fitting parameters, is Low cost and alLows the lifetime to be extracted directly from data collected at Lower frequencies. These characteristics make our method useful in encapsulated devices, applicable on wafers and devices in production-lines and where light excitation is difficult to access the active material. © 2010 Materials Research Society.