C-AFM
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Technical Concept |
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Conductive Atomic Force Microscopy (C-AFM) is one of AFM’s functions. It consists of a microscale cantilever with a sharp tip (probe) at the end and is used to obtain surface morphology with nanometer resolution. |
The AFM is developed from the scanning tunneling microscopy (STM), invented by Gerd Binning and Heinrich Rohrer in 1983, earning them a Nobel Prize in Physics in 1986. When an AFM tip is close to a sample surface, the repulsive forces between the apex and sample would bend the cantilever according to Hooke's Law. With force control via the feedback system, high spatial resolution surface morphology can be obtained.
The C-AFM is similar to AFM but holds an additional voltage bias applied between tips and samples when scanning. The electric characteristic of local areas, such as contacts, can be obtained by I-V measurements, and then failures with more accurate locations can be easily identified in the scanned image.
 Schematic figure showing the setup of a C-AFM |
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Electric Field Microscopy（EFM） |
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Equipment |
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Bruker INNOVA |
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Applications |
- It can be used in failure analysis for high resistance contact, junction leakage, gate oxide leakage, etc.
- To identify various contact types. (P+/N+/Poly CT)
- To diagnose failure mechanisms by comparing I-V curves on different contact types.
- To measure the I-V curve on a specific point.
- To provide information about surface potential and charge distribution.
 C-AFM provides surface topographies and I-V characteristics (a) Topography (b) Current with +1V bias (c)Current with -1V bias |
 The I-V curves of [on] four different points (A, B C, D) by C-AFM |
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Contact |
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