Locally delineating of junctions and defects by local cross-section electron-beam-induced-current technique

Abstract The local cross-section electron-beam-induced-current (EBIC) technique together with a focused ion beam (FIB) for cross-sectional viewing is discussed. The cross-section formed by FIB treatment on the ultra-large scale integrated (ULSI) device surface maintains sufficient electrical insulation between every node (including the PN junction). This was confirmed in advance using a test structure and an actual ULSI chip. High-resolution EBIC images could be obtained for some samples by irradiating a low-energy electron beam onto the FIB cross-section. This local cross-sectional EBIC technique is very useful for delineating PN junctions and pointing out defect portions upon the failure of ULSI devices. Furthermore, we found that the floating well, which was not connected to the outside electrode, was visualized by thinning the back (∼1 μm) of the cross-section with a FIB. It was clarified by electromotive current simulations that this phenomenon originates in the change in potential of the well due to the staying of the generated carriers which could not diffuse. This application is also very useful for the delineation of multiple well structures in ULSI devices.