EIES-IV GuardianTM 
 Thin Film Co-Deposition Control System based on Electron Impact Emission Spectroscopy
 
 
                                     
 

 

     Features
 
Control co-deposition of up to 8 materials
     - the ideal solution for CIGS thin films
 
Control deposition rates from 0.1 to 10,000 Å/sec
 
12 relay outputs and 16 digital inputs
Compatible with existing Sentinelâ sensors
Windows-based software for setup and operation
 
   
Additional Information
Data sheet / Sales Brochure (PDF)
Instruction Manual (PDF)
EIES tutorial (PDF)
     
  In Electron Impact Emission Spectroscopy (EIES), the material being deposited is excited by a thermionic emitter, which results in creation of photons. The light created passes through an optical filter to a photomultiplier tube (PMT) detector, which measures the intensity of emission of the passed wavelength. The Guardian then generates a signal to control the source for that material. Additional detectors, with appropriate optical filters, are used for multiple materials.   EIES is ideal for controlling simultaneous co-deposition of multiple materials in applications such as CIGS for photovoltaics, MBE, OLEDs, and superconducting thin films.  The block diagram below shows a typical Guardian EIES system configuration that might be used for fabrication of CIGS thin films. The Guardian controls the deposition rate of four materials, using EIES for three of the materials and a QCM for the fourth.
                                     
 

 
 
 
 
 
 
 
 
                                     
 
System Components & Configuration

A complete EIES Guardian system consists of at least one sensor, one detector, an optical filter, a controller/interface unit, and a PC-compatible computer (user-supplied) with Guardian software. Since EIES is generally used to control deposition of multiple materials, most EIES systems include additional sensors, detectors, optical components such as beam splitters, and QCMs for calibration or controlling deposition rate for some materials.

For a complete description and specifications for these components, please download our Guardian brochure.
 

Application Considerations

To configure an EIES system, consider the following: What are the primary and secondary emission wavelengths for your deposition materials? If different materials have peaks too close to each other, you may need to monitor a secondary wavelength, which has lower signal strength. During the deposition process, what background gases are present in your vacuum chamber, and what are the emission wavelengths for those gases? If emissions from background gases interfere with the deposition materials', a gas compensating sensor is recommended.

EIES is most effective with the uniquely defined spectra of atomic species.  Molecular species that generate unstable or broad emission spectra cannot be measured accurately.  EIES is not recommended for organic materials.

   
   
   
  A thorough discussion of EIES system configuration is beyond the scope of a webpage; numerous papers have been published and presented on the subject.  If EIES is a possible solution for your thin film process, please contact us for a discussion of your application.
                                     
                                     
                                     
                                     
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