A Contactless Method for Determining the Carrier Mobility Sum in Silicon Wafers

In this paper, we present a new method to determine the simultaneous injection and temperature dependence of the sum of the majority and minority carrier mobilities in silicon wafers. The technique is based on combining transient and quasi-steady-state photoconductance measurements. It does not require a full device structure or contacting but only adequate surface passivation. The mobility dependence on both carrier injection level and temperature, as measured on several test samples, is discussed and compared with well-known mobility models. The potential of this method to measure the impact of dopant concentration, compensation ratio, injection level, and temperature on the mobility is demonstrated.