Semiconductor Junction Temperature Measurement using the Electron Beam Induced Current Mode in the Scanning Electron Miscroscope

Abstract

A technique is described to accomplish junction temperature measurements in semiconductor devices in the scanning electron microscope. It details the procedure to produce high spatial resolution measurements and thermal gradient images of the true junction temperature. This approach combines the information in the electron beam induced current mode and the characteristic change in the forward voltage drop of a junction with temperature to produce a temperature reading at the site struck by the electron beam. Because this technique is essentially the same as the junction forward voltage drop method, the procedure first requires that the calibration curve of the junction under examination be determined. This calibration is performed in the SEM under the same conditions that the subsequent measurements are to be made. A means for heating the sample in the SEM is required. The critical SEM parameters are electron beam current and acceleration potential, as well as magnification or spot size. The electron beam of the SEM is the constant current source for the measurement and must be the same magnitude as in the calibration step.