Analog components are still an important aspect of our society's electronic portfolio. They play a role in the emerging and expanding 5G electronic industry, for instance. NPN bipolar junction transistors (BJTs) are the foundation of many analog circuits and have continually evolved to meet more demanding specifications. Certain embodiments of these NPNs, however, pose difficulties in failure analysis. Vertical NPN BJTs, with nanometer thick junctions extending several microns in length, are one such example. Although the high aspect ratio dimensions of these devices provide desired performance improvements, a subtle nanometer-scale defect anywhere along their length can cause electrical shifts detrimental to analog circuits. This paper examines the nature of these defects and explains how to isolate them using common failure analysis tools and special techniques.