On the current conduction mechanisms of CeO2/La2O3 stacked gate dielectric

SiC MIS structure with ultra-thin Al2O3as gate dielectric deposited by Atomic Layer Deposition(ALD) on epitaxial layer of 4H-SiC(0001)80N-/N+ substrate is fabricated. The experimental results indicate that the prepared ultra Al2O3gate dielectric exhibits good physical and electrical characteristics, including a high breakdown electrical field of 25MV/cm, excellent interface properties(2×1013cm-2•eV-1) and low gate-leakage current (IG=1×10-3A/㎝-2@EOX=8MV/cm). Analysis of current conduction mechanism in deposited Al2O3gate dielectric has also been systematically performed. The confirmed conduction mechanisms consisted of FP emission, FN tunneling, DT and Schottky emission. And the dominance of these current conduction mechanisms depended on applied electrical field, When the gate leakage current mechanism is dominated by FN tunneling, the barrier height of SiC/Al2O3is 1.4eV, which can meet the requirement of SiC MISFET devices.

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Structural, spectroscopic and passivation properties of a novel binuclear clamshell-type zinc(II) phthalocyanine as gate dielectric for OFET

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424618500013 ◽

2018 ◽

Vol 22 (01n03) ◽

pp. 64-76 ◽

Cited By ~ 2

Author(s):

Sebile Işık Büyükekşi ◽

Ahmet Altındal ◽

Nursel Açar ◽

Abdurrahman Şengül

Keyword(s):

Leakage Current ◽

Density Functional ◽

Gate Dielectric ◽

Field Effect Transistors ◽

Soret Band ◽

Quantum Yields ◽

Capacitance Density ◽

Fluorescence Quantum Yields ◽

Conduction Mechanisms ◽

Current Conduction

A novel clamshell-type binuclear zinc(II) phthalocyanine (2) was synthesized by cross condensation of the bisphthalonitrile (1) with 4-tert-butylphthalonitrile and zinc acetate in 1:10:4 ratio. The structure of the novel compound was characterized by elemental analysis, UV-vis, FT-IR (ATR), HR MALDI-TOF mass, [Formula: see text]H NMR, [Formula: see text]C DEPT NMR and [Formula: see text]H–[Formula: see text]H COSY NMR methods. Applying electronic absorption spectroscopy and density functional theory (DFT) revealed that in THF the geometry of 2 is twisted to adopt an intermediate clamshell conformation in which the spacing between the Zn centers is about 8.1Å, providing a very good account of the observed spectrum exhibiting the characteristic B (Soret) band at 347 nm and the Q band at 673 nm. In solution, 2 was found to exist in non-aggregated form. The calculated fluorescence quantum yields ([Formula: see text] 0.23 in THF and 0.10 in DMF) were relatively reduced in comparison to that of std ZnPc. In particular, understanding of leakage current conduction mechanisms in gate dielectrics is crucial for the development of field effect transistors with improved device performance. Analysis of the reverse bias current–voltage data indicated that the origin of leakage current conduction mechanisms in clamshell-type zinc(II) phthalocyanine is Poole-Frenkel emission. The capacitance density of 12.7 nF cm[Formula: see text] at 5 Hz. and 12.1 nF cm[Formula: see text] at 13 MHz was obtained with the FTO/Pc/Au sandwich structure.

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