Semiconductor behavior of Li doped ZnSnO thin film grown by mist-CVD and the associated device property

Jun Hyung Lim, Hyun Jun Jeong, Keun Tae Oh, Dong Hyun Kim, Joon Seok Park, Jin Seong Park

Research output: Contribution to journalArticle

Abstract

Lithium (Li)-doped zinc tin oxide (ZTO) films were successfully grown by mist chemical vapor deposition (mist-CVD) under ambient atmosphere at a relatively low process temperature (∼350 °C). The effects of Li incorporation on the chemical and physical properties of the host ZTO semiconductor were studied, along with the electrical characteristics of the associated thin film transistors (TFTs). The devices incorporating Li-ZTO active layers grown with a 1 mol % Li precursor exhibit superior electrical performance, with representative saturation mobility of 24.7 cm2/V and on/off ratio of ∼1010, compared to pure ZTO TFTs (exhibiting a mobility of 14.6 cm2/V and on/off ratio of ∼108). Under negative bias temperature stress (NBTS), the Li-ZTO TFTs undergo relatively small threshold voltage shifts (ΔVth) of approximately −0.42 V, while the undoped ZTO TFTs exhibit net ΔVth values near −3.21 V. Here it is suspected that Li ions enhance the device performance by contributing additional free carriers, while passivating the defects that act as carrier traps. Li doping is thus an effective way to improve both the charge transport properties and stability of ZTO semiconductor devices, which may be realized by means of a cost-effective mist-CVD process.

Original languageEnglish
Pages (from-to)881-886
Number of pages6
JournalJournal of Alloys and Compounds
Volume762
DOIs
Publication statusPublished - 2018 Sep 25

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Keywords

  • Metal oxide semiconductor
  • Mist chemical vapor deposition
  • Thin film transistor
  • Zn-Sn-O

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