| 摘要 |
A system for characterizing the electrical properties of semiconductor wafers with high surface state densities, such as GaN wafers, includes a support subsystem for supporting the semiconductor sample, at least one light source for illuminating a spot on the sample, and a detection subsystem for measuring the photovoltage signal produced from illumination of the sample. In use, the system utilizes in-line, non-contact photovoltage techniques that exploits the presence of the high surface state density and the known components of its associated electrostatic barrier as part of its novel characterization process. Specifically, the system illuminates the sample with one or more light beams that vary in photon energy and duration in order to excite charge carriers in specific layers of the sample while either preserving or collapsing the electrostatic barrier. In this manner, the system is able to electrically characterize individual or combined layers of the sample as well as embedded junctions. |
