New principle of contactless lifetime determination in semiconductor wafers

The principle of contactless determination of excess carrier lifetime or diffusion length in semiconductor wafers employs the magnetic flux created by the photomagnetoelectric (PME) current. Under certain conditions, the measured signal is nearly proportional to the lifetime according to a simple theory in which one-dimensional diffusion is considered. Experimental verification of the theory is presented. A sample region of a few square millimeters is sufficient for lifetime determination and lifetime up to 10−7 s or less is measurable by the method.