Modular Design Open Architecture

The unique, modular design of the MultiView 4000^TM allows for the future upgrade from one probe to two, three or four probes. The MultiView 4000^TM has a geometry that actually surpasses the open architecture of the Nanonics MultiView series, which established the uniquely open optical and electron/optical axes above the probe and below the sample scanner. The MultiView 4000^TM continues in this tradition and offers a completely free optical axis from above the probe, below the sample and for 270o around the probe. The MultiView 4000^TM boasts a 4.5mm working distance from above the probe for ultrahigh resolution optical or electron/optical viewing probes on opaque samples.

Start with one Probe	Upgrade to two probes	Upgrade to four probes

The Challenges of Multiprobe Scanning

Probes thwarted the dream of multiple probe scanned probe microscopy. Bulky and awkward piezo scanners, which stood upright, kept the probes apart when placed side-by-side. The probes themselves were not spatially friendly and did not allow the probe tips to approach one another.

Standard AFM probes do not allow close tip approach	Up right piezo scanners prevent close tip approach

Nanonics' Solutions

A) The 3D Flatscan^TM Scanner Technology
Unlike standard piezo scanners which keep probes separated, the 3D Flatscan^TM is the perfect solution for multiprobe scanning. The design of the 3D Flatscan^TM is a novel planar, folded-piezo, flexure scan design which provides the ultimate in AFM resolution (e.g. atomic steps in highly oriented pyrolytic graphite (HOPG). The large vertical (axial) displacement of up to 100 microns allows for the use of multiple probes as well as the tracking of structures with very large topographical features and simultaneous lateral scanning over large areas. The ultra-thin architecture of the 3D Flatscan^TM scanner provides the flexibility that is critical in developing a variety of different geometries of multiprobe systems. Furthermore, the 3D Flatscan^TM Scanner can be incorporated into systems where conventional scan stages are too bulky and geometrically limiting. Its minimal height of 7 mm allows for easy access with high powered microscope objectives from either above or below the scanning stages.

3D FlatScanTM Tip and Sample scan stages are ideal solution for Multiprobe SPM platform	Top View of 3D FlatScanTM scanner shows four scanning piezo tubes	A Friendly design of MultiProbe system based FlatScanTM tip and sample scan stages

B) Spatially Friendly Glass Based probes
While typical probes do not permit the probe tips to come within close proximity to one another, Nanonics has developed spatially and optically friendly glass based probes that allow for a close approach of the probe tips - a critical feature of multiprobe imaging systems. Such Nanonics' exposed probe technology permits the approach of two probes to within 10 nm, as well as independent scanning of each probe.
Not only do Nanonics' glass based probes offer excellent imaging in AFM modes - the probes have unparalleled aspect ratios and support deep trench imaging as well as side wall imaging. They also permit singular electrical imaging and thermal imaging with glass encased nanowires. Nanopipette probes further allow for gas and liquid chemical writing.

Nanonics' patented bent cantilevered glass probe	Online dual probes in contact with AFM feedback (side view)	Online four probes in contact with AFM feedback (top view 500x magnifications)

C) Normal Force Tuning Fork Feedback
Tuning fork feedback allows for a friendly geometry of the AFM feedback mechanism. Unlike the beam bounced feedback with laser, photodiode and bouncing optics, the tuning fork allows for online multiprobe feedback with no geometry complexity.
The MultiView 4000^TM employs the ultimate in SPM feedback technology. Normal force tuning fork technology with high Q factor phase feedback is used to permit unprecedented control of the probe tip/sample separation. Tuning forks in normal force mode with phase feedback not only permit the best AFM imaging available today but, in addition, there are no user adjustments needed with such a feedback mechanism. This allows for ease of operation with the ultimate in AFM resolution, better than any beam bounce technology. Furthermore, there is no feedback laser interference, for example, when working with semiconductor devices or fluorescent materials.

Nanopipette probe mounted on tuning fork

With multiple probes, previously unattainable measurements and analyses are now within reach. The MultiView 4000^TM features independent imaging with separate probes that allow for:

Dual Probe Electrical Measurements	Dual Probe Optical Measurements	NanoPumpProbe Optical Measurements
MultiProbe Apertureless NSOM	Dual Nano-Wire Thermal Conductivity Measurements	MultiProbe NanoChemical Writing
Multiprobe Optical and Thermal Profiling	Dual Probe Nanoindentation with On-line AFM/Raman Profiling

• Surface resistivity measurements - using two, three and four point geometries.
• Multiprobe thermal measurements and resistance measurements - on device structures or polymeric materials.
• Optical measurements with multiple NSOM probes for pump/probe measurements - on optical devices and optically active materials such as semiconductors with femtosecond time and nanometric spatial resolution.
• Optical or thermal desorption with multiple probes to excite and collect the desorbed species for chemical analysis - on chemical structures where spatially selective desorption of such species can be directly collected into a mass spectrometer for chemical analysis, with a second cantilevered nanopipette probe.
• Nanochemical writing with one probe while imaging with a second probe - on a wide variety of substrates using chemicals in the gas or liquid phase
• NanoIndentation with one probe, with simultaneous and accurate AFM and/or thermal mapping using a second probe - on polymeric, semiconductor or other materials.

The dream, now a reality, is opening the gateway to rewarding and productive avenues of research, development and quality control. Such avenues depend upon scanning multiple probes and the sample independently, while investigating diverse and functionally important sample parameters.

Dual Probe Electrical Measurements

Multiview 4000TM allows for unique online multiprobe electrical measurements through it’s accurate/nanometric manipulation and imaging capabilities. Up to four online probes are readily used with flexible positioning and nanomanipulation for localized providing bias, I-V localized measurements and multichannel imaging. The pictures above show a two probe electrical imaging of grooved Au coated surface on glass. One probe was used to bias the surface and a second probe for AFM/Electrical imaging.

Nanonics' ultrastable solid wire electrical probes allow for low contact resistance of a few tens of ohms and full insulation with glass up to the probe tip for high electro-potential resolution.

Glass coating insulation can be overcoated with metal to emulate coax geometries for ultrahigh sensitivity electrical imaging. Finally, the probe with its high cantilever design minimizes cantilever electrical interference.The properties of these electrical probes include:

• Ultrastable solid nanowires with exposed probe tips

• Low contact resistance and full insulation with glass up to the probe tip for high electro-potential resolution

• Glass coating insulation which can be overcoated with metal to emulate coax geometries for ultrahigh sensitivity electrical imaging.

• High cantilever design that minimizes cantilever electrical interference

Nanonics’ glass insulated nanowire probe for variety of electrical measurements, normal force sensing and multiprobe operation.

Dual Probe Optical Measurements

With two cantilevered, near-field optical probes with exposed tips, optical pump/probe experiments can now be performed. In this example light is injected through one probe and is guided through the sample which is a fiber. With the second probe in place, this injected light can be collected and analyzed both spatially and temporally.A diagramatic illustration is displayed above with a bright field optical microscopic image shown to the left. In this image two NSOM probes are seen in AFM contact with the input and output of the fiber waveguide. In the dark field image, the injected light from the illuminating 100nm near-field optical probe on the right is seen as a small spot of reflected light from the waveguide. This injected light is then guided through the fiber, and the intense spot on the left in the dark field image is collected and analyzed, both spatially and temporally, at the output of the waveguide with a second probe whose silhouette is clearly seen.

NanoPumpProbe Optical Measurements

Apertured NSOM probe is used to launch a 532nm laser on gold strip for near-field plasmons excitation (shown in topography image at left) and zoomed in the middle image. The right image is an NSOM collection mode obtained with a second probe shows plasmons propagation on the gold strip.Multiview 4000^TM system allows for multiprobe scan probe microscopy protocols for effective localized illumination of plasmonic structure with an apertured NSOM probe which produces all k-vectors and so it is most efficient for such plasmonic propagation. The propagating plasmons are collected with a second probe which has a very low dielectric constant and minimal perturbation of the plasmonic propagation.


MultiProbe Apertureless NSOM

Multiprobe Apertureless NSOM/ sSNOM: Efficient excitation of a plasmonic structure using an apertured NSOM probe (right probe) which produces all k vectors for effective plasmonic excitation while monitoring the same structure with a scattering probe (left probe). Right: Plasmonic propagation excited by an apertured NSOM probe while a second, low dielectric, non-perturbing, apertureless, fluorescent tipped probe is used for detection of the plasmon propagation

Scattering near-field scanning optical microscopy called ANSOM or sSNOM has been applied to look at plasmonic distribution. Unfortunately, the probes that need to be used in order to effectively scatter the plasmonic signal have significant perturbation on the plasmonic propagation because of the need to use probes with high dielectric constant to obtain effective signal to noise.The images above show an apertureless NSOM probe that is used as a localized detector of plasmonic propagation without significant effect on the distribution of plasmons. The image indicate that localized aperture NSOM illumination and apertureless monitoring of plasmons has significant potential for investigating plasmonic structures.


MultiProbe NanoChemical Writing



Fountain Pen Nanolithography (FPN) pipette probe allows for chemical nanowriting with one probe of the Multiview 4000TM system. A second AFM probe is used SPM imaging of the deposited materials. Letf: shows a nanopipette probe delivering a BSA protein on an aldehyde modified surface. Middle: shows the feature being imaging with a second AFM probe for obtaining the topography of the deposited BAS (right). With the Nanonics Fountain Pen Nanolithography [FPN] System, it is now possible to perform chemical nanolithography via liquid and gas delivery to the sample using the Nanonics' patented nanopipetteprobe, which acts simultaneously as an AFM tip and online delivery system. All Nanonics’ MultiViewTM SPM systems allow for FPN including the MultiView4000TM Multi-probe systems.

Dual Nano-Wire Thermal Conductivity Measurements

 

Nanonics has also developed Dual Wire Thermo-Resistance probes for use with the MultiView 4000™. In this specialized probe, two platinum wires are stretched through the nanopipette and are fused together at their tips. This fused junction has a resistance that is temperature-dependent. The unique probe allows for simultaneous measurement of surface topography and thermal conductivity even in intermittent contact mode. With multiple probes, heat can be introduced at specific locations and detected at other locations. The probes can also be used for resistance measurements. Only the MultiView 4000™ utilizing Dual Wire Thermo-Resistance probes with their exposed probe tip is capable of these functions.A thermal conductivity image of a static random access memory (SRAM) device is compared with the AFM topography. As contact is made in different regions of the SRAM with the thermal conductivity probe, the probe tip cools to different levels depending on the thermal conductivity of the material that is sitting under the chemically mechanically polished flat surface. The resulting image is obtained by determining the current alterations that had to be affected in order to keep the current flowing past the point resistance at a constant value.

Multiprobe Optical and Thermal Profiling

 

The MultiView 4000™ System simplifies the task of optically and thermally profiling on-line an optoelectronic device. Seen in these images (above) are the optical distribution of light in a quantum wire laser (NSOM) and the thermal distribution around the laser. The image below includes the p contact region in the thermal image. As can be seen, the thermal and light distribution bear no correlation to one another, but rather the thermal distribution is bowed towards the p contact where electrical charge is injected.

Dual Probe Nanoindentation with On-line AFM/Raman Profiling

 

The images above show the utility of two probes on-line in nanoindentation experiments. With the nanoindentation shown here it would be impossible to perform the imaging task with only the indenting probe. It also shows the great utility of the optically friendly nature of the multi probe system which in this case permits an on-line Raman map for chemically characterizing the nanoindentation. All Nanonics MultiView Systems can be integrated with any optical or electron/ion optical microscope system

Optical Integration

• Full integration with upright, inverted or dual (4 Pi) optical microscopes 
• Full integration with non-linear and multi-photon microscopes (e.g second harmonic generation microscopes)
• Completely free optical axis from above and below the sample
• Complete freedom of optical microscope nose piece rotation from above or below
• Open system architecture providing Transmission, Reflection and Collection modes

MultiView 4000TM (four probes) on dual optical microscope	MultiView 4000TM (two probes) on dual optical microscope	Free optical axis from top and bottom with high magnification and large NA objectives.

Integration with Complementary Techniques

• Online Raman
  
  

  MultiView 4000TM/HORIBA Xplora Raman Integration Package	MultiView 4000TM/Renishaw Invia Raman Integration Package

  
  
• Online Scanning Electron Microscopy - SEM
• Online Focused Ion Beam - FIB
• Online Dual Focused Ion Beam with scanning electron microscope - SEM