secm 470 150x150

The Model SKP470 Scanning Kelvin Probe operates using a vibrating capacitance probe and through a swept backing potential, the work function difference is measured between the scanned probe reference tip and sample surface.

A surface work function can be directly correlated to many aspects of surface condition including corrosion potential. Moreover, as the technique utilises a capacitance probe, such measurements can be made on surfaces in gaseous atmospheric conditions or even under insulating coatings.

The capacitance probe may also be used in height tracking mode to maintain a constant height between the probe tip and sample surface, allowing measurements to be made over uneven surfaces.

The SKP470 is the very latest development in Kelvin Probe technology incorporating many new features affording the user performance, flexibility and ease of use.

  • Specifications

  • Accessories

  • Documents

Signal chain

  • Phase sensitive detection using microprocessor controlled lock-in amplifier with digital dual phase oscillator and differential electrometer input.

Lock-in amplifier

  • Software controllable gain range. Gain 1-105.
  • Maximum theoretical sensitivity 0.5 µV FSD.
  • Output time constant 0.1, 1, 10 s.

Differential electrometer

  • 1015 Ohms input impedance.
  • Decade gain ranges 0 to 80 dB.
  • Common mode range ±12 V.

Vibration actuator: 

  • One dimensional low voltage piezo-electric actuator.

Vibration amplitude (±10%): Software set from 0 – 30 µm perpendicular to sample surface.

Backing potential controller

  • Potential range ±10 V
  • DAC resolution 300 μV.
  • Sampling 0.1 to 1000 Hz.
  • Type PID Controller

Probe type: SKPR Tungsten air gap.

Electrochemical sensitivity: Better than 0.15 meV.

Positioning system specifications

Stepper Motors

  • Scan Range (x,y,z): 110 mm x 110 mm x 110 mm
  • Minimal step size on all axes: 20 nm
  • Closed loop positioning linear zero hysteresis encoder with direct real-time readout of displacement in x, y and z
  • Linear position encoder resolution: 20 nm.
  • Max. scan speed: 10 mm/s
  • Measurement resolution: 32-bit decoder @ up to 40 MHz

Piezoelectric element (for z axis only)

  • Vibration range 20 nm – 2 µm peak to peak with 1 nm increments
  • Min. vibration resolution: 0.12 nm calculated (16-bit DAC on 4 µm)
  • Piezo crystal extension: 100 µm
  • Positioning resolution: 0.09 nm calculated (20-bit DAC on 100 µm)

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