Vapor Concentration Monitor IR-300

Overview

The Metal-Organic Chemical Vapor Deposition (MOCVD) process is widely used in the manufacture of LEDs, optical devices and other components. Liquid and solid precursors are delivered to the reaction chamber by controlling the temperature, pressure and the carrier gas flow rate (bubbling method). The in-line IR-300 Series measures and reports the precursor concentration in real time giving the user the following benefits:

  • Optimise process control to produce more high-grade devices
  • Improve device yield and reduce scrap
  • Improve reproducibility
  • Know when a bubbler will require exchanging
  • Extend MTTA
  • Reduce unplanned interventions
  • Reduce valuable precursor waste

Features

  • Real-time monitoring
    Fast response and excellent repeatability allow real time tracking of changes in vapor concentration
  • Multi-calibration Curve Function (Optional)
    Allows for concentration measurement of up to 3 chemicals or ranges
  • Multi-display Function
    The multi-display function on the top of the IR-300 unit gives the user onsite checking capability of concentration monitoring and precursor supply line status
  • Communications Function
    Connectivity through DeviceNet™, RS485 and analog communications
  • Simple, Compact Design
    With a face-to-face size of 124 mm, the unit’s compact and mount-orientation-free design allows for easy integration

A high optical intensity and long-life light source combined with high-speed signal processing enables the IR-300 Series to achieve faster, more repeatable responses to changes in precursor concentration. These features give the user a true understanding of the actual process though real-time inline concentration measurement.

Measurement Example of MOCVD Precursor

■Experiment flow sheet

IR-300 series flow

■Monitoring of precursor concentration change

Here is an example in which the concentration of the supplied precursor—which changes due to adjustment of the pressure in the bubbler by the back pressure regulator—was monitored in real time.

TEGa carrier gas flow rate

TMAI carrier gas flow

concentration calculation formula

Measurement Techniques

■Reliable, High-performance Non-dispersive Infrared Absorptiometry (NDIR)

The infrared absorptiometry method employed by the IR-300 Series uses the principle of measuring the absorption of gas molecules in infrared light emitted from an infrared light source. A sample output from a sample that has absorbed the gas being measured is compared to a reference output with no absorbance, and the result is converted into a gas concentration. The use of this double beam method enables long-term, stable measurement results to be obtained.

The optical system is made up of a light source, gas cell and double beam detectors. The stability of the double beam detector has been proven over a period of more than 40 years.


Manufactured by HORIBA STEC

Schematics

Dimensions of IR-300

Measurement Techniques

 

Reliable, High-performance
Non-dispersive Infrared Absorptiometry (NDIR)

The infrared absorptiometry method employed by the IR-300 Series uses the principle of the absorption by gas molecules of the infrared light emitted from an infrared light source. A sample output from a sample that has absorbed the gas being measured is compared to a reference output with no absorbance, and the result is converted into a gas concentration. The use of this double beam method enables long-term, stable measurement results to be obtained.

Non-dispersive Infrared Absorptiometry 

 

Non-dispersive Infrared Absorptiometry

The optical system is made up of a light source, gas cell and double beam detectors. The stability of the double beam detector has been proven over a period of more than 40 years.