Behavior of nitrogen atoms in SiC-SiO2 interfaces studied by electrically detected magnetic resonance

Umeda, T.; Esaki, Kazuki; Kosugi, Ryoji; Fukuda, Kenji; Ohshima, Takeshi; Morishita, Norio; Isoya, Junichi

doi:10.1063/1.3644156

Cited by 58 publications

(53 citation statements)

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“…Their amounts exceeded over 1×10 14 cm -2 , which is three orders of magnitude larger than the reduction in D it (10 10 −10 11 cm -2 ) [4]. The secondary change is the doping of shallow nitrogen donors into the channel region [8]. The amount of the doped nitrogen donors was estimated to be ~10 12 cm -2 [9], which is comparable to the concentration of free carriers in the channel region [8].…”

Section: Understanding the Characteristics Of Si-face Mos Interfacesmentioning

confidence: 99%

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(Invited) SiC MOS Interface States: Difference between Si Face and C Face

et al. 2013

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This paper discusses the differences between Si-face and C-face MOS interfaces in 4H-SiC MOSFETs. The two interfaces exhibit unique electrical characteristics, which will be linked with the differences in interface defects. We carried out an electrically detected magnetic resonance (EDMR) study on Si-face and C-face 4H-SiC MOSFETs, and found that there are different types and different amounts of interface defects on each interface. We discussed the EDMR results in comparison with the electrical characteristics of Si-face and C-face MOSFETs. SiC MOS Interfaces: Si face vs. C faceSilicon carbide is a promising wide-band-gap semiconductor for high-performance (highvoltage and high-temperature operational, low-energy-loss, and high-energy-density) power electronics. The main devices of SiC will be Schottky barrier diodes (SBD) and metal-oxide-semiconductor field effect transistors (MOSFETs) on 4H-SiC wafers. Both the devices expectedly have wide applications in power electronics. Currently, the SBD devices have been practically commercialized, but the MOSFETs still have some barriers for a mass commercialization. The major barriers are caused by the quality of SiC MOS interfaces. From a structural view point, SiC-SiO 2 interfaces are similar to the wellknown Si-SiO 2 interface, as discussed in our earlier paper [1]. However, from an electrical view point, SiC MOS interfaces are much inferior to those of silicon. The important issues in 4H-SiC MOSFETs are (1) a serious degradation of the channel mobility (field-effect mobility, µ FE ), (2) a lower stability of the threshold voltage (V th ), and (3) a lower reliability of gate dielectric layers, as compared to the case of silicon. Such properties are strongly dependent not only on MOS processes [oxidation and postoxidation anneal (POA), etc.] but also on the type of initial surfaces. In 4H-SiC wafers, typical surfaces are 4H-SiC(0001) (Si face) and 4H-SiC(0001 _

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Section: Understanding the Characteristics Of Si-face Mos Interfacesmentioning

confidence: 99%

“…In fact, we have studied shallow interface states in Si-face MOSFETs using low-temperature electrically detected magnetic resonance (EDMR) spectroscopy [8]. In addition to EDMR, interfacial nitrogen atoms have been characterized by X-ray photoelectron spectroscopy (XPS) [4].…”

Section: Understanding the Characteristics Of Si-face Mos Interfacesmentioning

confidence: 99%

(Invited) SiC MOS Interface States: Difference between Si Face and C Face

et al. 2013

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“…In another study where we applied electrically detected magnetic resonance to the channel region of (0001) 4H-SiC MOSFETs, 15 we found that nitrogen shallow donors were doped in the channel region after post-nitridation annealing. This result can be explained by supposing that some part of the fixed nitrogen atoms are incorporated into the SiC layer during nitridation where they occupy substitutional sites (i.e., carbon sites), and are activated as shallow donors.…”

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Fixed nitrogen atoms in the SiO2/SiC interface region and their direct relationship to interface trap density

Kosugi

Umeda

Sakuma

2011

Applied Physics Letters

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Nitrogen atoms fixed in the SiO2/SiC interface region were studied by x-ray photoelectron spectroscopy (XPS) and capacitance-voltage (C-V) measurements. A thin oxide film (<5 Å) formed during annealing in an NO atmosphere on a (0001) 4H-SiC surface, incorporating nitrogen atoms into the interface region. Even after complete removal of the oxide layer by etching in hydrofluoric acid, XPS spectra clearly showed a strong N 1 s peak, revealing the presence of fixed nitrogen atoms with an areal density of 1014 cm−2 in the interface region. To evaluate their influence on interface traps, metal-oxide-semiconductor capacitors were formed by deposition of a gate oxide layer. The fixed nitrogen atoms decrease the interface trap density after post-annealing at high temperature.

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“…5 Å) SiO 2 layer formed on SiC during the annealing by sustained etching in hydrofluoric acid. The same group [7] demonstrated by the electrically detected magnetic resonance technique that shallow donor levels can be associated with a fraction of the incorporated N atoms. However, information on the electrical activation of the incorporated nitrogen and on the depth extension of the nitrogen profile is still lacking.…”

Section: Introductionmentioning

confidence: 99%

A look underneath the SiO₂/4H-SiC interface after N₂O thermal treatments

Fiorenza¹,

Giannazzo²,

Swanson³

et al. 2013

Beilstein J. Nanotechnol.

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SummaryThe electrical compensation effect of the nitrogen incorporation at the SiO2/4H-SiC (p-type) interface after thermal treatments in ambient N2O is investigated employing both scanning spreading resistance microscopy (SSRM) and scanning capacitance microscopy (SCM). SSRM measurements on p-type 4H-SiC areas selectively exposed to N2O at 1150 °C showed an increased resistance compared to the unexposed ones; this indicates the incorporation of electrically active nitrogen-related donors, which compensate the p-type doping in the SiC surface region. Cross-sectional SCM measurements on SiO2/4H-SiC metal/oxide/semiconductor (MOS) devices highlighted different active carrier concentration profiles in the first 10 nm underneath the insulator–substrate interface depending on the SiO2/4H-SiC roughness.The electrically active incorporated nitrogen produces both a compensation of the acceptors in the substrate and a reduction of the interface state density (D it). This result can be correlated with the 4H-SiC surface configuration. In particular, lower D it values were obtained for a SiO2/SiC interface on faceted SiC than on planar SiC. These effects were explained in terms of the different surface configuration in faceted SiC that enables the simultaneous exposition at the interface of atomic planes with different orientations.

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Behavior of nitrogen atoms in SiC-SiO2 interfaces studied by electrically detected magnetic resonance

Cited by 58 publications

References 17 publications

(Invited) SiC MOS Interface States: Difference between Si Face and C Face

(Invited) SiC MOS Interface States: Difference between Si Face and C Face

Fixed nitrogen atoms in the SiO2/SiC interface region and their direct relationship to interface trap density

A look underneath the SiO₂/4H-SiC interface after N₂O thermal treatments

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Behavior of nitrogen atoms in SiC-SiO2 interfaces studied by electrically detected magnetic resonance

Cited by 58 publications

References 17 publications

(Invited) SiC MOS Interface States: Difference between Si Face and C Face

(Invited) SiC MOS Interface States: Difference between Si Face and C Face

Fixed nitrogen atoms in the SiO2/SiC interface region and their direct relationship to interface trap density

A look underneath the SiO2/4H-SiC interface after N2O thermal treatments

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Product

Resources

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A look underneath the SiO₂/4H-SiC interface after N₂O thermal treatments