InGaZnO4 -based thin film transistors using room-temperature grown Mg2Hf5O12 gate insulator

Dong Hun Kim, Hyungtak Seo, Kwun Bum Chung, Nam Gyu Cho, Ho Gi Kim, Il Doo Kim

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

This study reports the dielectric and leakage current properties of Mg 2Hf5 O12 thin films deposited at room temperature by radio-frequency magnetron sputtering. Polycrystalline Mg 2Hf5 O12 thin films showed a reasonably high dielectric constant (εr =22) and greatly enhanced leakage current characteristics (<2× 10-7 A/ cm2) compared to the leakage current (∼2× 10-5 A/ cm2) of HfO2 thin films at 0.4 MV/cm. A bandedge spectroscopic analysis revealed lower conduction bandedge defect states and a greater p-type-like Fermi energy level of Mg 2Hf5 O12 compared to the HfO2 thin films. The suitability of Mg2Hf5 O12 films as gate insulators for low voltage operating InGaZnO4 thin film transistors (TFTs) was investigated. All room-temperature processed InGaZnO 4 TFTs on plastic substrates exhibited a high field effect mobility of 27.32 cm2 /Vs and a current on/off ratio of 4.01× 106. The threshold voltage and subthreshold swing were 2 V and 440 mV/dec, respectively. The fabrication and compositional manipulation method of the Mg 2Hf5 O12 films described in this work is simple and versatile, providing fascinating opportunities for new high- k gate dielectrics.

Original languageEnglish
Pages (from-to)H964-H968
JournalJournal of the Electrochemical Society
Volume157
Issue number10
DOIs
StatePublished - 2010

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