Atomic Force Microscope MultiMode

Topography measurements:

 Contact Mode in air and in fluids measures topography by sliding the probe's tip across the sample surface: high spatial resolution can be obtained, but may damage soft surfaces and adsorbed layers.

 Tapping Mode in air and in fluids measures topography by tapping the surface with an oscillating tip: less destructive to the surface as compared to contact mode. Now this is technique to choice for most AFM work.

Non-contact AFM measures topography by sensing van der Waals attractive forces between the surface and the probe tip held above the surface: lower resolution than either contact AFM or Tapping Mode.

 

Special Modules:

The modules are interchangeable in minutes so it is easy to switch from one application to another.

"Nanoman" abilities:

  • Nanolithography - scratching.
  • Nanolithography - oxidation.
  • Nanomanipulation of nanoscale objects.

Friction and elasticity:

  • Lateral Force Microscopy measures frictional forces between the probe tip and sample surface.
  • Force Modulation measures relative elasticity / stiffness of surface features.
  • Phase Microscopy provides image contrast caused by differences in surface adhesion and viscoelasticity.
  • HarmoniX Microscopy is a new AFM mode that operates simultaneously with TappingMode. By measuring the torsional amplitude at exact integer multiples (harmonics) of the TappingMode drive frequency, it is possible to extract the variation in force between the tip and the sample when the tip goes through a period of the tapping oscillation. A correctly chosen single harmonic can provide compositional mapping of a complex composite material while providing the same resolution as a tapping image (~5nm).
  • Nanoindentation is technique to study mechanical properties of thin films.It involves forcing a sharp diamond indenter into the surface of a thin film on a substrate, while measuring the force imposed and the corresponding displacement of the indenter. The load and displacement resolution is sufficient to obtain useful mechanical property data as thin film as about 100 nm.

Electrical and magnetic properties:

  • Interleave (second pass) Imaging (LiftModeTM): A combined two-pass technique that separately measures topography (using Tapping Mode) and another selected property (e.g. electric or magnetic force), using the topographical information to track the probe tip at a constant height above the surface.
  • Magnetic Force Microscopy (MFM): measures magnetic force gradient distribution above the sample surface in the "second pass", with a special magnetic tip.
  • Electric Field Microscopy (EFM): measures electric field gradient distribution above the sample surface. EFM is similar to MFM, with a conducting tip and applied tip-sample bias.
  • Electrochemical Microscopy (ECAFM and ECSTM) measures the surface structure and properties of conducting materials immersed in electrolyte solution with or without potential control.
  • Scanning Tunneling Microscopy (STM) measures topography of surface electronic states using tunneling current which is dependent on the separation between the prbe tip and a conductive sample surface. An optional Low0Current STM Converter allows operationin the subpicoamper tunneling current region which can be useful when scanning poorly conductive samples.
  • Tunneling-AFM (TUNA): including the local I-V measurements, but with ultra-low current measurement capability, between 80 fA to 120 pA.
  • SSRM maps variations in majority carrier concentration in semiconductor materials. A conductive probe is scanned in contact mode across the sample, while a DC bias is applied between the tip and sample. The resulting current between the tip and sample is measured (referencing it to an internal resistor) using a logarithmic current amplifier. This yields a local resistance measurement, which is mapped to generate the SSRM image.
  • Torsion Resonance Mode (TR) measures and controls dynamic lateral forces between the AFM probe tip and sample surface. This mode allows working close to the surface without actually contacting it, providing both high spatial resolution, and options for close range measurements (such as TUNA and lateral magnetic force). 

MultiMode heater/cooler line provides increased thermal-control convenience to life sciences and polymers research.

Specifications: 

Scanner Piezo Resolution

16 bits (all axes)

Scanner size (X, Y axis)

Scanner "J"  - 100 µm

Scanner "E" -  10 µm

Water-Cooled Scanner  - 125 µm

Vertical range (Z axis)

Scanner "J" - 5.5 µm,

Scanner "E" - 3.5 µm

Water-Cooled Scanner  - 5 µm

Noise

<3Å in vertical (Z) dimension with vibration isolation

Lateral resolution

The radius of curvature of the end of the tip will determine the highest lateral resolution obtainable with a specific tip. The sidewall angles of the tip will also determine its ability to probe high-aspect-ratio features.

Typical accuracy

1%

Maximum accuracy

2%

Orthogonality

2 degrees

Max. sample size

Samples up to 10 mm diameter and 6 mm thick

Small samples*

Magnetic holder available for mounting small samples on mounting pucks Smooth samples can be attached to the chuck using chuck vacuum.

Wet samples

Optional fluid cell with / without temperature control in liquids. Useful range  is 4- 50 ºC in water

Optical microscope

10X Nikon objective, 450X magnification range with 14-inch image. 12.7 mm travel two-axis stage.

Heater / Cooler

Provides samples heating and temperature control from -35 ºC to 100 ºC  for samples (0.6x0.6x0.5 mm) in air or other inert gases.

SSRM

Image carrier concentrations 1015 – 1020 carries/cm3.

Resistance is measured using logarithmic current amplifier with range 10pA -0.1 mA.

Extended TUNA

Range: 150 fA to 2000 nA; Noise: 150 fA RMS in pA range, 10 pA RMS in nA range. A bias of mV to 12 V can be applied.