Automated Spatial Langmuir Probe that Allows Plasma Measurements on the Move

The Langmuir Spatial Probe from Impedans is equipped with an automated linear drive to scan across plasma and obtain measurements of plasma parameters at various locations. The spatial profiling of the plasma can help overcome problems involving uniformity.

The Langmuir Spatial Probe quantifies the spatial profile of the plasma, such as ion current density, plasma density, plasma potential, floating potential, and the electron energy distribution function (EEDF).

The probe uses the latest probe theory available, based on Orbital Motion Limited and shifting to Allen Boyd Reynolds as the pressure regimes vary, to make up for collisions.


  • Single and double probe combined
  • Automated spatial scanning
  • High-speed acquisition
  • Advanced RF compensation


  • Process development
  • Fundamental research
  • Model validation
  • Equipment design


The Langmuir Spatial Probe is the main instrument used to quantify the internal parameters of plasma, using an automated linear drive to scan through plasma bulk. Important parameters measured are floating potential, electron density, electron temperature, ion density, plasma potential, and the EEDF.

The Langmuir Spatial Probe offers plasma characterization measurements in DC, microwave, RF, pulsed and continuous plasma. The probe examines ion and electron trajectories to acquire exact measurements of the plasma parameters in a broad array of plasma applications. The Langmuir Spatial Probe is the world’s fastest and most dependable Langmuir probe (with a time resolution of 12.5 ns).

Besides reliability and speed, the Langmuir Probe offers the most sophisticated, trusted, and completely automated data analysis in real time.

The Impedans Langmuir Probe system is provided with interchangeable single and double probe tips (at no additional cost) that can be used with the same electronics system. It is also provided with a completely automated linear drive system. This enables users to perform experiments across various reactors, and facilitates plasma characterization measurements in reactors that have a weak ground return.

The Langmuir Spatial Probe is used to determine the plasma process uniformity and repeatability. It helps in gaining insights into plasma variations and the effect on surface treatment. The probe is an important plasma process diagnostic to comprehend the correlation between plasma inputs and the plasma state.

Plasma Parameters Measured

  • Plasma potential uniformity
  • Plasma density uniformity
  • Ion current density uniformity
  • Floating potential uniformity
  • EEDF

Measurement Functionality

Time-Averaged Measurements

This functionality offers an average over time of the plasma parameters quantified by the Langmuir Spatial Probe in the plasma bulk.

Time-Resolved Measurements

Using this functionality, users can synchronize the plasma parameters quantified by the Langmuir Spatial Probe with an external synchronization signal. Then, they can acquire comprehensive information on the plasma parameters as a function of phase or time during the synchronization pulse period. Usually, the pulse period is on a timescale of milliseconds to microseconds.

Time-Trend Measurements

This functionality enables users to get information on the changes in the plasma parameters as time progresses in a specific process. This feature does not necessitate external synchronization, and the timescales can vary from seconds to hours.

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