Non-destructive, non-contact characterization of silicon using photothermal radiometry

Non-destructive characterization of silicon at some depth within a wafer is a difficult task, but is necessary for any realistic on-line process monitoring for large semiconductor devices. The techniques that appear most promising at the moment rely on the detection of optically injected carriers by either a Schottky contact or the attenuation of a probe laser by the carriers. Photothermal methods have also recently been used for semiconductor evaluation, and this paper presents a development of the photothermal technique that enables non-contact, non-destructive evaluation of carrier lifetime in a silicon sample.