Abstract: A semiconductor wafer is tested by heating an electrical contact to a temperature sufficient to desorb water vapor and/or organic material from a surface thereof. The semiconductor wafer is also heated to a temperature sufficient to desorb water vapor and/or organic material from a top surface thereof. The heated surface of the contact is caused to touch the heated top surface of the semiconductor wafer. An electrical stimulus is applied between the heated surface of the contact and the heated top surface of the semiconductor wafer when the surface of the contact is touching the top surface of the semiconductor wafer. A response of the semiconductor wafer to the applied electrical stimulus is measured and at least one electrical property of the semiconductor wafer is determined from the measured response.

Abstract: To determine a concentration of defects and/or impurities in a semiconductor wafer, a first value of current is caused to flow in the semiconductor wafer having a substrate of semiconducting material. The semiconductor wafer is exposed to a pulse of light whereupon electron-hole pairs generated in the semiconductor wafer in response to the light pulse cause the current to increase to a second value. After termination of the light pulse, the rate of change of the current from the second value toward the first value is determined. A concentration of defects and/or impurities in the semiconductor wafer is determined as a function of the rate of change.