Characteristics of the electromagnetic interference shielding effectiveness of Al-doped ZnO thin films deposited by atomic layer deposition

Yong June Choi, Su Cheol Gong, David C. Johnson, Stephen Golledge, Geun Young Yeom, Hyung-Ho Park

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Abstract

The structural, optical, and electrical properties of Al-doped ZnO (ZnO:Al) thin films deposited by atomic layer deposition (ALD) with a modified precursor pulse sequence were investigated to evaluate the electromagnetic interference shielding effectiveness (EMI-SE). A Zn-Al-O precursor exposure sequence was used in a modified ALD procedure to result in better distribution of Al 3+ ions in the ZnO matrix with the aim of reducing the formation of complete nano-laminated structures that may form in the typical alternating ZnO and Al 2 O 3 deposition procedure. The ALD dopant concentration of the ZnO:Al films was varied by adjusting the dopant deposition intervals of the ZnO:ZnAlO precursor pulse cycle ratios among 24:1, 19:1, 14:1, and 9:1. The lowest obtained resistivity and average transmittance in the visible region (380-780 nm) were 5.876 × 10 -4 Ω cm (carrier concentration of 6.02 × 10 20 cm -3 and Hall mobility of 17.65 cm 2 /V s) and 85.93% in the 131 nm thick ZnO:Al(19:1) film, respectively. The average value of the EMI-SE in the range of 30 MHz to 1.5 GHz increased from 1.1 dB for the 121 nm thick undoped ZnO film to 6.5 dB for the 131 nm thick ZnO:Al(19:1) film.

Original languageEnglish
Pages (from-to)92-97
Number of pages6
JournalApplied Surface Science
Volume269
DOIs
Publication statusPublished - 2013 Jan 1

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All Science Journal Classification (ASJC) codes

  • Surfaces, Coatings and Films

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