Negative charge trapping effects in Al2O3 films grown by atomic layer deposition onto thermally oxidized 4H-SiC

Schilirò, Emanuela; Nigro, Raffaella Lo; Fiorenza, Patrick; Roccaforte, Fabrizio

doi:10.1063/1.4960213

Cited by 44 publications

(25 citation statements)

References 26 publications

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“…However, to guarantee the reliability of power devices, insulators with high critical breakdown field, large band gap, and high melting point are desired. So far, the most robust gate insulation solution is the SiO 2 , but recent literature is exploring alternative solutions, such as Al 2 O 3 [4] and AlON [5]. Moreover, the channel resistance R ch can be lowered by reducing the channel length.…”

Section: Introductionmentioning

confidence: 99%

Characterization of SiO2/4H-SiC Interfaces in 4H-SiC MOSFETs: A Review

2019

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This paper gives an overview on some state-of-the-art characterization methods of SiO2/4H-SiC interfaces in metal oxide semiconductor field effect transistors (MOSFETs). In particular, the work compares the benefits and drawbacks of different techniques to assess the physical parameters describing the electronic properties and the current transport at the SiO2/SiC interfaces (interface states, channel mobility, trapping phenomena, etc.). First, the most common electrical characterization techniques of SiO2/SiC interfaces are presented (e.g., capacitance- and current-voltage techniques, transient capacitance, and current measurements). Then, examples of electrical characterizations at the nanoscale (by scanning probe microscopy techniques) are given, to get insights on the homogeneity of the SiO2/SiC interface and the local interfacial doping effects occurring upon annealing. The trapping effects occurring in SiO2/4H-SiC MOS systems are elucidated using advanced capacitance and current measurements as a function of time. In particular, these measurements give information on the density (~1011 cm−2) of near interface oxide traps (NIOTs) present inside the SiO2 layer and their position with respect to the interface with SiC (at about 1–2 nm). Finally, it will be shown that a comparison of the electrical data with advanced structural and chemical characterization methods makes it possible to ascribe the NIOTs to the presence of a sub-stoichiometric SiOx layer at the interface.

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Section: Introductionmentioning

confidence: 99%

Characterization of SiO2/4H-SiC Interfaces in 4H-SiC MOSFETs: A Review

2019

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“…4, reporting the cyclic C-V curves acquired from depletion to accumulation and backward in the two cases, the hysteresis was almost completely suppressed in the annealed oxide; i.e., in the order of 1×10 11 cm -2 . However, in literature Al2O3 thin films synthesized using different techniques (e.g., ALD) suffer of similar electron trapping phenomena, likely due to the presence of oxygen vacancies [7].…”

Section: Resultsmentioning

confidence: 99%

Properties of Al2O3 thin films deposited on 4H-SiC by reactive ion sputtering

Fiorenza

Vivona

Franco

et al. 2019

Materials Science in Semiconductor Processing

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In this work, the electrical properties of Al2O3 films deposited by reactive ion sputtering were investigated by means of morphological, chemical and electrical characterizations. This insulating layer suffers of an electron trapping that is mitigated after the rapid thermal annealing (RTA). The RTA improved also the permittivity (up to 6ε0), although the negative fixed charge remains in the order of 10 12 cm -2 . However, the temperature dependent electrical investigation of the MOS capacitors demonstrates that the room temperature Fowler-Nordheim electron barrier height of 2.37 eV lies between the values expected for SiO2/4H-SiC and Al2O3/4H-SiC systems.

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“…A small voltage shift (∆V th ) is attributable to the different charging conditions of the interface states with different chemical treatments. The interface state trap densities (D it ) can be estimated using [13,14]:…”

Section: Resultsmentioning

confidence: 99%

Surface Treatments on the Characteristics of Metal–Oxide Semiconductor Capacitors

Horng

Tseng

2018

Crystals

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The properties of metal-oxide semiconductor (MOS) capacitors with different chemical treatments have been examined in this study. A MOS capacitor consists of an Al 2 O 3 /n-GaN/AlN buffer/Si substrate. Four chemical treatments, containing organic solvents, oxygen plasma and BCl 3 plasma, dilute acidic and alkali solvents, and hydrofluoric acid, were used to reduce the metal ions, native oxides, and organic contaminants. The n-GaN surface was treated with these chemical treatments before Al 2 O 3 was grown on the treated n-GaN surface to reduce the interface state trap density (D it ). The value of D it was calculated using the capacitance-voltage curve at 1 MHz. The D it of a u-GaN surface was modified using various solutions, which further influenced the contact properties of GaN.surface conditions before dielectrics material deposition to further modify the AlGaN/GaN HEMT [6]. The metal-oxide-semiconductor HEMTs(MOS-HEMTs) structure using different dielectrics material causes different device performance of MOS-HEMTs, such as different C-V characteristics, specific resistance (R on ), breakdown voltage, D it value, saturation drain current of the devices [7]. The MOS-HEMTs structure using Al 2 O 3 [8] will be effective to enhance the breakdown voltage generated from the gate leakage. The ALD is a surface-controlled layer-by-layer process for the deposition of thin films with atomic layer accuracy. The Al 2 O 3 used for MOS-HEMTs not only improve the basic electronic properties but also show low leakage current and high breakdown voltage. In this study, four chemical pretreatments were used for MOS capacitors before atomic layer deposition (ALD) of Al 2 O 3 to modify the surface quality. The characteristics of MOS capacitors and the ohmic contact characteristics of GaN with the four chemical treatments are discussed. Experiments

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Negative charge trapping effects in Al2O3 films grown by atomic layer deposition onto thermally oxidized 4H-SiC

Abstract: Influence of deposition temperature of thermal ALD deposited Al 2 O 3 films on silicon surface passivation AIP Advances 5, 067113 (2015);

Cited by 44 publications

References 26 publications

Characterization of SiO2/4H-SiC Interfaces in 4H-SiC MOSFETs: A Review

Characterization of SiO2/4H-SiC Interfaces in 4H-SiC MOSFETs: A Review

Properties of Al2O3 thin films deposited on 4H-SiC by reactive ion sputtering

Surface Treatments on the Characteristics of Metal–Oxide Semiconductor Capacitors

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