Practical Electron Microscopy and Database

Figure 255a shows resistive contact issues with a resistive interface, which refers to the presence of increased electrical resistance at the interface between two materials, often a metal and a semiconductor. In semiconductor devices, resistive contacts can arise due to a number of factors, such as poor adhesion, improper alloying during silicide formation, or contamination at the interface. This resistive interface could involve a failure mechanism where poor silicide formation (e.g., cobalt silicide, nickel silicide) results in incomplete or irregular contact formation. This leads to localized areas of increased resistance, often due to spiking, voiding, or incomplete reactions between the metal and silicon. Such defects can degrade the performance of the device by increasing power consumption and reducing speed. The resistive nature of the interface might be visible in the TEM image as irregularities or discontinuities in the silicide formation. These could be areas where the metal-semiconductor reaction is non-uniform, leading to areas of higher resistance. Detecting such defects with TEM is crucial for identifying root causes of device failures, allowing for process optimization to reduce or eliminate resistive contacts.

[1] Raghaw S. Rai and Swaminathan Subramanian, Role of transmission electron microscopy in the semiconductor industry for process development and failure analysis, Progress in Crystal Growth and Characterization of Materials, 55, pp.63-97, 2009.