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Thermal Desorption Spectroscopy

Thermal Desorption Spectroscopy (TDS) analyzes desorbed gas from the surface and in-depth from the specimen by heating it in high vacuum. Analyzing the desorbed gas it enables to find the way to improve the process or to estimate the cause of problem. TDS provides qualitative and semi-quantitative analysis of desorbed gases.


Specimen is heated in high vacuum by radiation from the lamp. Heated by light absorption the specimen desorbs gas. The desorbed gas is analyzed by mass spectrometer.


Thermal Desorption Spectroscope



Principle of TDS

Thermocouple for specimen
Vacuum chamber
Q-pole Mass
Quartz holder
SiC stage
Thermocouple for stage temp
Infrared radiation
Quarts guide for infrared heater


  • Size of specimen : Max. 10mm×10mm Thickness 4mm
  • Temperature: RT to 1400degC (Stage temp)
    *Temperature is precisely controlled by embedded thermocouple.
    *Specimen temperature is lower than stage temperature.

  • Specimen which does not absorb infra red is applicable using black stage.


  【Mode of analysis adopting to the purpose】

    1. Qualitative analysis (Scanning mode)
      - m/z range from 1 to 199
      - Scanning from m/z 1 to 199 in 5 seconds at every measurement temperature

    2. Semi-quantitative analysis (MID mode)
      - High sensitivity and capable of trace gases detection
      - Scanning of specified 8 m/z in 5 seconds at every temperature
       *This mode is recommended after scanning mode.

    3. Quantitative and Qualitative analysis (Bar mode)
      - Measurement for specified m/z range (integer)
      - Background level is lower than that of scanning mode
      - Quantitativeness is close to that of MID mode when m/z is less than 50



Example: Desorbed gas from Si-oxide film

【Qualitative analysis m/z 1 to 20】

Qualitative analysis m/z= 1 to 20


【Estimated Model of gas desorption】
Model of gas desorption

[Last updated: August 22, 2017]

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