First-principles investigations for oxidation reaction processes at 4H-SiC/SiO2 interface and its orientation dependence

Akiyama, Toru; Ito, Ayako; Nakamura, Kohji; T, Ito; Kageshima, Hiroyuki; Uematsu, Masashi; Shiraishi, Kenji

doi:10.1016/j.susc.2015.06.028

Cited by 41 publications

(45 citation statements)

References 34 publications

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“…281) The activation energy for dry oxidation of the SiC(0001) surface was estimated to be 2.9 eV, which corresponds to the energy barrier against formation of CO molecules at the SiO 2 /SiC interface. 283) Systematic studies have also revealed that, even for hightemperature oxidation, unintentional oxide growth during cooling determines D it at the interface. A clear dependence of D it and μ FE on the oxidation temperature was observed by employing a low-oxygen-partial-pressure cooling procedure, and MOSFET performance was improved by gate oxidation at 1450 °C.…”

Section: Challenges To Achieving An Ideal and Pure Interfacementioning

confidence: 99%

Defect engineering in SiC technology for high-voltage power devices

Kimoto

Watanabe

2020

Appl. Phys. Express

204

100

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Major features of silicon carbide (SiC) power devices include high blocking voltage, low on-state loss, and fast switching, compared with those of the Si counterparts. Through recent progress in the material and device technologies of SiC, production of 600–3300 V class SiC unipolar devices such as power metal-oxide-semiconductor field-effect transistors (MOSFETs) and Schottky barrier diodes has started, and the adoption of SiC devices has been demonstrated to greatly reduce power loss in real systems. However, the interface defects and bulk defects in SiC power MOSFETs severely limit the device performance and reliability. In this review, the advantages and present status of SiC devices are introduced and then defect engineering in SiC power devices is presented. In particular, two critical issues, namely defects near the oxide/SiC interface and the expansion of single Shockley-type stacking faults, are discussed. The current physical understanding as well as attempts to reduce these defects and to minimize defect-associated problems are reviewed.

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Section: Challenges To Achieving An Ideal and Pure Interfacementioning

confidence: 99%

Defect engineering in SiC technology for high-voltage power devices

Kimoto

Watanabe

2020

Appl. Phys. Express

204

100

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“…5,6 This obviously comes from the poor controllability of the SiO 2 /SiC interface formed by the oxidation. In order to achieve the microscopic identification and then increase the controllability of the interface, intensive works have been done both experimentally 5,[7][8][9][10][11][12][13] and theoretically [14][15][16][17][18][19][20] . However, there is still no definite explanation for the deterioration mechanism of electron mobility.…”

Section: Introductionmentioning

confidence: 99%

“…SiC devices such as Schottky diodes and field-effect transistors are already fabricated and in production. , However, there still remains much room for the improvement when considering the good bulk properties of SiC; for example, the electron mobility in the devices is typically less than 10% of the bulk value. , This obviously comes from the poor controllability of the SiO 2 /SiC interface formed by the oxidation. In order to achieve the microscopic identification and then increase the controllability of the interface, intensive work has been done both experimentally ,− and theoretically. − However, there is still no definite explanation for the deterioration mechanism of electron mobility. Thus, accurate calculations which clarify the mechanism of the oxidation of SiC surfaces and then provide a theoretical framework to discuss the nature of the SiO 2 /SiC interface are in great demand.…”

Section: Introductionmentioning

confidence: 99%

First-Principles Calculations That Clarify Energetics and Reactions of Oxygen Adsorption and Carbon Desorption on 4H-SiC (112̅0) Surface

et al. 2017

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We report static and dynamic first-principles calculations that provide atomistic pictures of the initial stage of the oxidation processes occurring at the (1120) surface of 4H-SiC. Our results unveil reaction pathways and their associated free-energy barriers for the adsorption of oxygen and the desorption of carbon atoms. We find that oxygen adsorption shows structural multi-stability and that the surface-bridge sites are the most stable and crucial sites for subsequent oxidation. We find that an approaching O2 molecule is adsorbed, then dissociated and finally migrates toward these surface-bridge sites with a free-energy barrier of 0.7 eV at the (1120) surface. We also find that a CO molecule is desorbed from the metastable oxidized structure upon the overcoming of a free-energy barrier of 2.4∼2.6 eV, thus constituting one of the annihilation process of C during the oxidation. The results of the CO molecule desorption on the (1120) surface are compared with the (0001) surface. A catalytic effect of dangling bonds at the surface, causing a drastic reduction of the CO desorption energy, is found on the (0001) surface and the microscopic picture of the effect is ascribed to an electron transfer from the Si to C dangling bonds. The intrinsic (1120) surface does not show this catalytic effect, and this is because the surface consists of an equal amount of Si and C dangling bonds and the electron transfer occurs before the desorption.

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“…Figure 1 shows the atomic structure of the interface. Since the transport calculation for the interface between crystalline SiC and amorphous SiO 2 is computationally difficult, the crystalline interface model generated in previous works [11,17] is used to examine the electron-transport property of the 4H-SiC(0001)/SiO 2 interface. Our two-dimensional slab model with a 11 Å vacuum region contains a crystalline substrate with 6 planes of SiC bilayers connected to β-tridymite SiO 2 with a thickness of 9 Å.…”

mentioning

confidence: 99%

Intrinsic origin of electron scattering at the4H-SiC(0001)/SiO2interface

2017

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We introduce a first-principles study to clarify the carrier-scattering property at the SiC/SiO 2 .Interestingly, the electron transport at the conduction-band edge is significantly affected by the introduction of oxygen, even though there are no electrically active defects. The origin of the large scattering is explained by the behavior of the internal-space states (ISSs). Moreover, the effect of the ISSs is larger than that of the electrically active carbon-related defects. This result indicates that an additional scattering not considered in a conventional Si/SiO 2 occurs at the SiC/SiO 2 .

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First-principles investigations for oxidation reaction processes at 4H-SiC/SiO2 interface and its orientation dependence

Cited by 41 publications

References 34 publications

Defect engineering in SiC technology for high-voltage power devices

Defect engineering in SiC technology for high-voltage power devices

First-Principles Calculations That Clarify Energetics and Reactions of Oxygen Adsorption and Carbon Desorption on 4H-SiC (112̅0) Surface

Intrinsic origin of electron scattering at the4H-SiC(0001)/SiO2interface

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