Thin film thickness measurement with triple gas electron multiplier detector by 55Fe radiation transmission and background detection using energy distribution analysis

Rafael Maria Gutierrez, Freddy Fuentes

Research output: Contribution to journalArticlepeer-review

Abstract

The quality control of thin film thickness measurements through the transmission and counting of beta and X-ray radiation has achieved very competitive precision with values to 0.2%. However, when the attenuated intensities by the thin film under measurement is above 90%, the method of counting beta or X-ray radiation generates a dramatic degradation in the precision to 30%. This work presents a new method to obtain and analyze thicknesses of aluminum and copper thin films using energy distribution information provided by a triple gas electron multiplier detector (3GEM). The method is based on the ratio of the peak of the Landau distribution generated by the background detection and the peak of the Gaussian distribution of soft X-ray photons generated by the radiation transmission through the thin films emitted by a 55Fe radiation source. The results improve the thickness measurement precision with respect to the radiation counting method when the intensity attenuated by the thin film is greater than 95% compared to precision values less than or equal to 30% obtained with the counting method to values below 10% achieved with the newly reported energy distribution method.

Original languageEnglish (US)
Pages (from-to)539-549
JournalInstrumentation Science and Technology
Volume48
Issue number5
StatePublished - Sep 2 2020

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