Relationship between 4H-SiC∕SiO2 transition layer thickness and mobility

Biggerstaff, Trinity Leigh; Reynolds, C. L.; Zheleva, T.; Lelis, Aivars J.; Habersat, Daniel B.; Haney, Sarah K.; Ryu, Sei‐Hyung; Agarwal, Anant; Duscher, Gerd

doi:10.1063/1.3144272

Cited by 96 publications

(92 citation statements)

References 17 publications

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“…Going from SiC to SiO 2 across the interface, the C/Si (O/Si) ratio decreases (increases) gradually without any observable enrichment in any of the elements. In particular, no C-rich area is detected in the SiC or in the bulk SiO 2 as it was previously reported [3][4][5][6][7] . From these profiles, a region of continuously varying composition including the three elements (Si, C and O) named transition layer (TL)…”

Section: Resultssupporting

confidence: 68%

“…Compositional curves appear identical for both MOSFETs, p-epi and p-impl, as it can be observed on the EELS ratio 6 profile across the 4H-SiC/SiO 2 interface along the < 100 1 > direction (Fig. 1c and 1d, respectively).…”

Section: Resultsmentioning

confidence: 54%

“…This degradation was related to electrically active defects at the SiC/SiO 2 interface, such as C clusters [3,4] and/or changes in the C/Si ratio across the SiC/SiO 2 interface. They were observed by different transmission and scanning transmission electron microscopy (TEM and STEM, respectively) techniques, such as high resolution transmission electron microscopy (HRTEM), Z-contrast imaging [5,6] and Electron Energy Loss Spectroscopy (EELS) [7]. On the other hand, these compositional variations were not observed in later works.…”

Section: Introductionmentioning

confidence: 90%

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Atomic scale characterization of SiO2/4H-SiC interfaces in MOSFETs devices

Beltrán

Duguay

Strenger

et al. 2015

Solid State Communications

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Abstract. The breakthrough of 4H-SiC MOSFETs is stemmed mainly due to the mobility degradation in their channel in spite of the good physical intrinsic material properties. Here, two different n-channel 4H-SiC MOSFETs are characterized in order to analyze the elemental composition at the SiC/SiO 2 interface and its relationship to their electrical properties.Elemental distribution analyses performed by EELS reveal the existence of a transition layer between the SiC and the SiO 2 regions of the same width for both MOSFETs despite a factor of nearly two between their electron mobility. Additional 3D compositional mapping by atom probe tomography corroborates these results, particularly the absence of an anomalous carbon distribution around the SiC/SiO 2 interface.

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Section: Resultssupporting

confidence: 68%

Section: Resultsmentioning

confidence: 54%

Section: Introductionmentioning

confidence: 90%

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Atomic scale characterization of SiO2/4H-SiC interfaces in MOSFETs devices

Beltrán

Duguay

Strenger

et al. 2015

Solid State Communications

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“…[7][8][9] In addition, the conduction band offset in SiO 2 /4H-SiC systems is smaller than that in SiO 2 /Si systems. Nevertheless, for years the conduction mechanism in SiO 2 /SiC systems has been believed to be FN tunneling.…”

Section: Introductionmentioning

confidence: 97%

Temperature-dependent analysis of conduction mechanism of leakage current in thermally grown oxide on 4H-SiC

Sometani

Okamoto

Harada

et al. 2015

Journal of Applied Physics

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The conduction mechanism of the leakage current of a thermally grown oxide on 4H silicon carbide (4H-SiC) was investigated. The dominant carriers of the leakage current were found to be electrons by the carrier-separation current-voltage method. The current-voltage and capacitance-voltage characteristics, which were measured over a wide temperature range, revealed that the leakage current in SiO2/4H-SiC on the Si-face can be explained as the sum of the Fowler-Nordheim (FN) tunneling and Poole-Frenkel (PF) emission leakage currents. A rigorous FN analysis provided the true barrier height for the SiO2/4H-SiC interface. On the basis of Arrhenius plots of the PF current separated from the total leakage current, the existence of carbon-related defects and/or oxygen vacancy defects was suggested in thermally grown SiO2 films on the Si-face of 4H-SiC.

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“…Recently, high-resolution TEM, Z-contrast scanning TEM, and spatially resolved EELS studies have revealed a transition layer (∼3 nm) at the interface due to the formation of a ternary Si-C-O phase. [34][35][36] The results indicated that the presence of a transition layer at the SiO 2 /SiC interface could lead to the mobility degradation. On the contrary, Watanabe et al suggested that an interfacial transition layer should be ruled out as a cause of electrical degradation.…”

Section: Introductionmentioning

confidence: 94%

Structural and electronic properties of the transition layer at the SiO2/4H-SiC interface

Zhao

Wang

2015

AIP Advances

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Using first-principles methods, we generate an amorphous SiO2/4H-SiC interface with a transition layer. Based this interface model, we investigate the structural and electronic properties of the interfacial transition layer. The calculated Si 2p core-level shifts for this interface are comparable to the experimental data, indicating that various SiCxOy species should be present in this interface transition layer. The analysis of the electronic structures reveals that the tetrahedral SiCxOy structures cannot introduce any of the defect states at the interface. Interestingly, our transition layer also includes a C-C=C trimer and SiO5 configurations, which lead to the generation of interface states. The accurate positions of Kohn-Sham energy levels associated with these defects are further calculated within the hybrid functional scheme. The Kohn-Sham energy levels of the carbon trimer and SiO5 configurations are located near the conduction and valence band of bulk 4H-SiC, respectively. The result indicates that the carbon trimer occurred in the transition layer may be a possible origin of near interface traps. These findings provide novel insight into the structural and electronic properties of the realistic SiO2/SiC interface.

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Relationship between 4H-SiC∕SiO2 transition layer thickness and mobility

Cited by 96 publications

References 17 publications

Atomic scale characterization of SiO2/4H-SiC interfaces in MOSFETs devices

Atomic scale characterization of SiO2/4H-SiC interfaces in MOSFETs devices

Temperature-dependent analysis of conduction mechanism of leakage current in thermally grown oxide on 4H-SiC

Structural and electronic properties of the transition layer at the SiO2/4H-SiC interface

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