Mechanisms responsible for improvement of 4H–SiC/SiO2 interface properties by nitridation

Afanasʼev, Valeri; Stesmans, André; Ciobanu, Florin; Pensl, Gerhard; Cheong, Kuan Yew; Dimitrijev, Sima

doi:10.1063/1.1532103

Cited by 189 publications

(102 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This is much higher than observed densities of the established intrinsic defects in thermally grown a-SiO 2 . The absence of a comparable density of electron traps in bulk a-SiO 2 and the strong sensitivity of electron trapping to the incorporation of nitrogen at the interface, 28,29 suggest that electron trapping at 2.8 eV deep centers takes place not on pre-existing defects but rather in the oxide network itself. Whether the substrate plays any role in stabilizing these traps remains unclear.…”

Section: Introductionmentioning

confidence: 99%

Nature of intrinsic and extrinsic electron trapping in SiO2

et al. 2014

View full text Add to dashboard Cite

Using ab initio calculations we demonstrate that extra electrons in pure amorphous SiO2 can be trapped in deep band gap states. Classical potentials were used to generate amorphous silica models and density functional theory to characterize the geometrical and electronic structures of trapped electrons. Extra electrons can trap spontaneously on pre-existing structural precursors in amorphous SiO2 and produce ≈ 3.2 eV deep states in the band gap. These precursors comprise wide (≥132 • ) O-Si-O angles and elongated Si-O bonds at the tails of corresponding distributions. The electron trapping in amorphous silica structure results in an opening of the O-Si-O angle (up to almost 180 • ). We estimate the concentration of these electron trapping sites to be ≈ 4 × 10 19 cm −3 . The structure of these centers is similar to that of Ge and Li electron centers in α-quartz.

show abstract

Section: Introductionmentioning

confidence: 99%

Nature of intrinsic and extrinsic electron trapping in SiO2

et al. 2014

View full text Add to dashboard Cite

show abstract

“…2,7,8,[24][25][26][27] However, the reasons for these improvements have not yet been well understood either, and are subject to controversial discussions in the literature. This is partly due to the fact that the mechanism of the dry oxidation of SiC is still unclear.…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of the mechanism of dry oxidation of4H-SiC

et al. 2005

View full text Add to dashboard Cite

Possible defect structures, arising from the interaction of O 2 molecules with an ideal portion of the SiC/ SiO 2 interface, have been investigated systematically using density functional theory. Based on the calculated total energies and assuming thermal quasiequilibrium during oxidation, the most likely routes leading to complete oxidation have been determined. The defect structures produced along these routes will remain at the interface in significant concentration when stopping the oxidation process. The results obtained for their properties are well supported by experimental findings about the SiC/ SiO 2 interface. It is found that carbon-carbon bonds can explain most of the observed interface states but not the high density near the conduction band of 4H-SiC.

show abstract

“…We used 100 kHz as the measurement frequency to avoid the decrease in accumulation capacitance due to series resistance. Parallel shifts in the C-V curves in the positive direction were observed for the dry and NO-annealed oxides that depended on the start voltage, suggesting that the electrons were captured in the traps located on the oxide side of the interface [14,15]. The electrons are thought to be captured by the NITs whose energy position is aligned close to the conduction band edge of 4H-SiC [11][12][13][14] because the Fermi level is very close to the conduction band edge in strong accumulation conditions.…”

Section: Resultsmentioning

confidence: 90%

“…Of these, NITs may play a dominant role because they are considered to create trap levels close to the conduction band edge of 4H-SiC at a high density [11][12][13][14]. It has been reported that NITs can be effectively removed by the incorporation of N [15], Na [16], K [17], and P [18] as revealed either by using low-temperature capacitance-voltage (C-V ) [15,18] or thermal dielectric relaxation current (TDRC) [16][17][18] measurements. It is interesting to note that improved field-effect mobilities can be obtained by utilizing oxides incorporating N [3,4], Na [5], and P [6], and thus we can assume that the NIT density is closely related to the field-effect mobility.…”

Section: −1mentioning

confidence: 99%

Effect of boron incorporation on slow interface traps in SiO2/4H-SiC structures

et al. 2017

View full text Add to dashboard Cite

The reason for the effective removal of interface traps in SiO 2 /4H-SiC (0001) structures by boron (B) incorporation was investigated by employing lowtemperature electrical measurements. Low-temperature capacitance-voltage and thermal dielectric relaxation current measurements revealed that the density of electrons captured in slow interface traps in B-incorporated oxide is lower than that in dry and NO-annealed oxides. These results suggest that near-interface traps can be removed by B incorporation, which is considered to be an important reason for the increase in the field-effect mobility of 4H-SiC metal-oxide-semiconductor devices. A model for the passivation mechanism is proposed that takes account of stress relaxation during thermal oxidation.

show abstract

Mechanisms responsible for improvement of 4H–SiC/SiO2 interface properties by nitridation

Cited by 189 publications

References 20 publications

Nature of intrinsic and extrinsic electron trapping in SiO2

Nature of intrinsic and extrinsic electron trapping in SiO2

Theoretical study of the mechanism of dry oxidation of4H-SiC

Effect of boron incorporation on slow interface traps in SiO2/4H-SiC structures

Contact Info

Product

Resources

About