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Water‐Induced Scandium Oxide Dielectric for Low‐Operating Voltage n‐ and p‐Type Metal‐Oxide Thin‐Film Transistors
Author(s) -
Liu Ao,
Liu Guoxia,
Zhu Huihui,
Song Huijun,
Shin Byoungchul,
Fortunato Elvira,
Martins Rodrigo,
Shan Fukai
Publication year - 2015
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201502612
Subject(s) - materials science , thin film transistor , dielectric , thin film , x ray photoelectron spectroscopy , optoelectronics , gate dielectric , oxide , equivalent oxide thickness , threshold voltage , high κ dielectric , transistor , gate oxide , analytical chemistry (journal) , nanotechnology , chemical engineering , electrical engineering , voltage , metallurgy , chemistry , layer (electronics) , chromatography , engineering
Solution‐processed metal‐oxide thin films based on high dielectric constant ( k ) materials have been extensively studied for use in low‐cost and high‐performance thin‐film transistors (TFTs). Here, scandium oxide (ScO x ) is fabricated as a TFT dielectric with excellent electrical properties using a novel water‐inducement method. The thin films are annealed at various temperatures and characterized by using X‐ray diffraction, atomic‐force microscopy, X‐ray photoelectron spectroscopy, optical spectroscopy, and a series of electrical measurements. The optimized ScO x thin film exhibits a low‐leakage current density of 0.2 nA cm −2 at 2 MV cm −1 , a large areal capacitance of 460 nF cm −2 at 20 Hz and a permittivity of 12.1. To verify the possible applications of ScO x thin films as the gate dielectric in complementary metal oxide semiconductor (CMOS) electronics, they were integrated in both n‐type InZnO (IZO) and p‐type CuO TFTs for testing. The water‐induced full oxide IZO/ScO x TFTs exhibit an excellent performance, including a high electron mobility of 27.7 cm 2 V −1 s −1 , a large current ratio ( I on / I off ) of 2.7 × 10 7 and high stability. Moreover, as far as we know it is the first time that solution‐processed p‐type oxide TFTs based on a high‐ k dielectric are achieved. The as‐fabricated p‐type CuO/ScO x TFTs exhibit a large I on / I off of around 10 5 and a hole mobility of 0.8 cm 2 V −1 at an operating voltage of 3 V. To the best of our knowledge, these electrical parameters are among the highest performances for solution‐processed p‐type TFTs, which represents a great step towards the achievement of low‐cost, all‐oxide, and low‐power consumption CMOS logics.