Interface carbon defects at 4H-SiC(0001)/SiO2 interfaces studied by electron-spin-resonance spectroscopy

We study an electron-spin-resonance (ESR) signal of carbon dangling-bond defects at 4H-SiC(0001)/SiO2 interfaces, which we call an “interface carbon defect.” The ESR signal is close to a c-axial type of the PbC centers (interfacial carbon dangling bonds) that have originally been found in porous-SiC...

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Bibliographic Details
Published in:Applied physics letters 2018-08, Vol.113 (6)
Main Authors: Umeda, T., Kim, G.-W., Okuda, T., Sometani, M., Kimoto, T., Harada, S.
Format: Article
Language:English
Subjects:
Applied physics
Carbon
Carrier density
Defects
Electron spin
Electron traps
Free electrons
MOSFETs
Oxidation
Silicon carbide
Silicon dioxide
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Summary:We study an electron-spin-resonance (ESR) signal of carbon dangling-bond defects at 4H-SiC(0001)/SiO2 interfaces, which we call an “interface carbon defect.” The ESR signal is close to a c-axial type of the PbC centers (interfacial carbon dangling bonds) that have originally been found in porous-SiC/SiO2 interfaces. The interface carbon defects were always formed with an areal density of 3–4 × 1012 cm−2 after the standard dry oxidation of 4H-SiC(0001) surfaces. They act as electron traps and decrease the amount of free electrons in the channel region, consequently reducing the field-effect mobility of Si-face 4H-SiC MOSFETs. They were eliminated by optimum post-oxidation anneals (POAs) in either NO or POCl3 environment. Furthermore, POCl3 POAs at 1000 °C introduced a high density (1.7 × 1012 cm−2) of phosphorus donors into the channel region, increasing the free-carrier density as compared with the case of NO POAs.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.5041059