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Quantum RFEA System - Retarding field energy analyser
Quantum RFEA System

The Quantum system is comprised of a retarding field energy analyser with integrated quartz crystal microbalance (QCM), used to measure the ion energy distribution function (IEDF) and the ion-neutral deposition ratio at a surface inside a plasma reactor. This system measures and displays deposition rates, IEDF, ion flux and the DC bias voltage at the surface on which the sensor is deployed. Using crystals coated with specified materials, the system can also measure etch rates of ions and neutrals. The system was designed to be mounted on electrically biased surfaces including radio-frequency (RF). A unique shielding structure allows accurate detection of the millivolt level, 6 MHz, crystal oscillation frequency in the presence of RF bias levels up to 900 V peak-to-peak. Unlike other QCM systems, no water cooling of the crystals is needed. A compensation crystal, mounted next to the measurement crystal, is not exposed to plasma particles and used to compensate for temperature effects on the oscillating frequency of the measurement.

Key Features
Measure the Ion Flux and Ion Energy Distribution with energy range up to 2000eV (process dependant).
Deposition rate resolution of 12.3 ng cm-2. Suitable for Grounded, Floating and RF Biased Conditions.
Measures deposition rates and etch rates of ion and neutral species.
Holders with different geometries available upon request.
Fully automated software with IED and deposition rate modes.
Replaceable sensor elements with different sensitivities.
Sensor elements and holder available in anodised aluminium, bare aluminium, or stainless-steel.
Key Benefits
Designed for transferring deposition processes from R&D to production environments.
Provides in-situ measurement of the IED and deposition rates under plasma processing conditions.
Provides insight for fundamental research and for plasma model validation.
Generate process data for customer escalations or product marketing.
Correlate process performance with the key plasma process drivers (Ion energy and Ion flux)
Measure the Ion/Neutral ratio, a key parameter for thin film properties.
Use crystals coated with your specific material o investigate etch rates of ions and neutral species

Electronics Box

The Quantum sensor, Electronics box is calibrated accurately for voltages ranging from -2000V to +2000V and currents ranging from 100 pA to 60 mA.

Model NumberProduct NameDescription


Quantum Electronics Unit

Compatible for Quantum holders.



The vacuum Feed-through transmits electrical signals by connecting the Electronics Box from Outside the Vacuum chamber to the Quantum Sensor inside the vacuum chamber.

Model NumberProduct NameDescription


Quantum Feed-through

Compatible for Quantum holders.


Button Probes

The Button Probes of the sensor are designed to be replaceable in the field. Lifetime is typically 10 to 100 hours of plasma exposure, depending on chamber conditions. For use in deposition systems the sensing element will survive 10 microns of deposition before needing to be replaced.

High Pressure Buttons, which extend the maximum pressure range to 1.5 Torr, are available upon request.

Anodised Aluminium as standard. Bare Aluminium and Stainless-Steel available upon request.

Model NumberDensity RangeDescription


Low Density

Ion Flux Range 0.001 to 3 Am-2


Standard Density

Ion Flux Range 0.01 to 50 Am-2


High Density

Ion Flux Range 0.1 to 700 Am-2


Calibration Button

Used as a temperature reference for the quartz crystal microbalance



The main purpose of the sensor holder is to hold the replaceable Button Probe sensors. It can withstand temperature up to 100 °C without the need for cooling.

Anodised Aluminium as standard. Bare Aluminium and Stainless-Steel available upon request.

Model NumberHolder SizeDescription


100 mm Holder

1 Measurement Button, 1 Calibration Button


300 mm Holder

1 Measurement Button, 1 Calibration Button

RFEA Probe Specifications
Number of sensors (Button Probes)
1 (plus one Calibration button)
Probe configuration
Button Probe diameter (sensing element)
Holder diameter
100mm, 300 mm diameter options as Standard (custom available)
Holder thickness
Max. operating temperature
Button Probe material
Aluminium, anodised aluminium, stainless steel
Holder material
Aluminium, anodised aluminium, stainless steel
RFEA Probe cable length
650 mm (custom available)
Flange Type
CF40 as standard, KF40 and custom options available
Quantum System Specifications
Ion Energy Range
2000 eV
Ion Flux
0.001 to 3 Am-2 (low density Button Probe)
0.01 to 50 Am-2 (standard Button Probe)
0.1 to 700 Am-2 (high density Button Probe)
Pressure Range
≤ 300 mTorr
IEDF Resolution
±1 eV nominal
Ion Density Range
1012 to 1018 m-3
Max. RF Bias Voltage (applied to probe)
900 V (peak to peak)
Max. DC Bias Voltage
-1940 V
Bias Frequency Range
100 kHz to 80 MHz
* @ 13.56 MHz. Reduces to 300 V @ 60 MHz
Crystal Monitor Specifications
Frequency Range
3.5 - 6.1 MHz
Frequency Resolution
1 Hz
Mass Resolution (at crystal)
12.3 ng cm-2
Mass Resolution (at sensor surface)
372.73 ng cm-2
Film Thickness Resolution (Copper)
0.4 nm
Measurement Update Rate
1 Hz

Software Screenshots

Deposition Rate Data for Neutrals alone and for Ions + Neutrals together.
IEDF versus Ion Energy data.
Talk to Us Today

Do you want to learn more about our sensors or applications? Contact us and a member of the team will get back to you