Analysis of electrical breakdown failures by means of SFM-based methods
Abstract
Electrical breakdown failures in Si devices may occur within ESD (electrostatic discharge) protection structures as well as in other parts of the circuit due to electrical overstress. Those kinds of failure very often show topographical irregularities due to material flow within the breakdown channel. Depending on the current and correlated material, flow channels may be observable by means of SEM. For devices tested with CDM (charge device model), which implies very low breakdown currents, this task gets more difficult to fulfil even with a high-resolution SEM. SFM offers an extremely high resolution in the lateral as well as vertical direction, and is therefore chosen as an appropriate tool for imaging small features. Besides the purely topographical information, additional data obtained in parallel, such as conductivity or capacitance, can give the necessary hints for an unequivocal interpretation. Here a comparison of SEM and SFM results demonstrates the capabilities of SFM topography analysis in the identification of breakdown channels. Furthermore, conducting SFM and capacitance investigations illustrates the usefulness of parallel detection of topography and current (or capacitance respectively) for the explanation of breakdown phenomena and material transport.
- Publication:
-
Applied Physics A: Materials Science & Processing
- Pub Date:
- 1998
- Bibcode:
- 1998ApPhA..66S1063B