PeakForce sMIM

Scanning microwave impedance microscopy (sMIM) is an AFM-based technique for materials and device characterization that does not require making electrical contact between the sample and the substrate.It works by reflecting the microwave signal from the tip-sample interface to reveal the electrodynamic properties of the sample surface and sub surface due to the penetration of the near field signal.

By AC-biasing the sample or device under test, sMIM also provides carrier profiling (dC/dV) capability similar to traditional scanning capacitance microscopy (SCM). In the same way, it also uniquely offers mapping of nonlinear resistive properties (dR/dV). With both the sMIM and its AC-sample-bias modulated signals, sMIM is suitable for studying surfaces with complex composition or devices under test with a broad dynamic range, e.g., metallic, semiconducting, and insulating domains. As a near-field method, the resolution is only limited by the tip radius of the probe, and it can easily achieve a lateral resolution of <30 nm for electrical mapping. These unique capabilities make sMIM superior to other AFM-based electrical modes for a broad range of applications.

When empowered by Bruker’s unique PeakForce Tapping, sMIM greatly expands its applications to previously challenging measurements on fragile samples, while providing simultaneous mapping of correlated mechanical properties. The ability to directly image the local variation of a sample at the tens of nanometer length scales of sMIM has stimulated new areas of research and applications, such as CNTs, nanoparticle oxide films, subsurface patterns, and semiconductor devices. The versatility of sMIM with PeakForce Tapping empowers material researchers and device engineers to explore the basic principles underlying functionality, and to perform more advanced and complete materials characterization and device failure analysis.

High-resolution sMIM with PeakForce Tapping® delivers:

Greatest repeatability
Extension of technique to delicate structures
Simultaneous nanoelectrical and nanoMechanical Characterization

Bruker’s sMIM enables:

Nanoelectric measurements of semiconductors, conductors, insulators, and metals
Direct and simultaneous measurements of capacitance and resistivity
Measurements of carrier profiling derived from dC/dV
Loss coefficient amplitude and phase from dR/dV
Site-specific Capacitance-Voltage and Resistivity-Voltage Spectroscopy” [ The C-V and R-V curves. The C-V curve is difficult for other electrical technique. SCM is almost impossible to do it.]

PeakForce sMIM applications include:

PeakForce sMIM imaging and static random access memory (SRAM)
Inverted vertical insulated gate bipolar transistors (IGBTs)
Complementary metal-oxide semiconductor (CMOS) Image Sensors
Semiconductor Metal Oxide Films
Buried Structures
SSRM

sMIM images of an SRAM sample. (A) Topography channel,15 μm x 7.5 μm, and ~150 nm tall features; (B) sMIM-C channel as a skin covers on topography; (C) sMIM dC/dV phase channel on topography; (D) sMIM dC/dV amplitude channel on topography. Sample courtesy of Greg Michael Pitner and Professor H. – S. Philip Wong, Stanford University.