Scanning Probe Microscopy Applications in Failure Analysis of Semiconductor Devices

Scanning probe microscopy (SPM) is widely used for fault isolation as well as diagnosing leakage current, detecting open circuits, and characterizing doping related defects. In this article, the author presents two SPM applications that are fairly uncommon but no less important in the scope of failure analysis. The first case involves the discovery of nano-steps on the surface of high-voltage NFETs, a phenomenon associated with stress-induced crystalline shift along the (111) silicon plane. In the second case, the author uses an AFM probe in the conductive mode to correlate tunneling current distribution with hot spots in high-k gate oxide films, which is shown to be a better indicator of oxide quality than rms surface roughness.