Influence of growth conditions on basal plane dislocation in 4H-SiC epitaxial layer

Ohno, Toshiyuki; Yamaguchi, Hiroshi; Kuroda, Shunsuke; Kojima, Kazutoshi; Suzuki, Takaya; Arai, Kazuo

doi:10.1016/j.jcrysgro.2004.04.044

Cited by 101 publications

(94 citation statements)

References 14 publications

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“…It can be seen by the significantly lower BPD density and higher TED density in the epitaxial layers compared to the substrate; this is consistent with previous results. 9 …”

Section: Resultsmentioning

confidence: 99%

“…5,6 The presence and propagation of the BPD in the epitaxial layers are known to cause a drift of the forward voltage in bipolar devices during operation. 7,8 The use of a high growth rate or low C/Si during the epitaxial growth increases the density of BPD in the epitaxial layers, according to the studies made by Ohno et al 9 Also the density of BPD in the epitaxial layers has been reduced using in situ growth interrupts 10 or molten potassium hydroxide (KOH) etching. 11 However, the main disadvantages of using 4 offangle substrate are usually the formation of step bunching 12,13 or triangular defects of different shapes and widths 14 on the epitaxial layers.…”

Section: à3mentioning

confidence: 99%

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Reduction of structural defects in thick 4H-SiC epitaxial layers grown on 4° off-axis substrates

Yazdanfar

Ivanov

Pedersen

et al. 2013

Journal of Applied Physics

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By carefully controlling the surface chemistry of the chemical vapor deposition process for silicon carbide (SiC), 100 lm thick epitaxial layers with excellent morphology were grown on 4 off-axis SiC substrates at growth rates exceeding 100 lm/h. In order to reduce the formation of step bunching and structural defects, mainly triangular defects, the effect of varying parameters such as growth temperature, C/Si ratio, Cl/Si ratio, Si/H 2 ratio, and in situ pre-growth surface etching time are studied. It was found that an in-situ pre growth etch at growth temperature and pressure using 0.6% HCl in hydrogen for 12 min reduced the structural defects by etching preferentially on surface damages of the substrate surface. By then applying a slightly lower growth temperature of 1575 C, a C/Si ratio of 0.8, and a Cl/Si ratio of 5, 100 lm thick, step-bunch free epitaxial layer with a minimum triangular defect density and excellent morphology could be grown, thus enabling SiC power device structures to be grown on 4 off axis SiC substrates. V C 2013 AIP Publishing LLC.

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“…It can be seen by the significantly lower BPD density and higher TED density in the epitaxial layers compared to the substrate; this is consistent with previous results. 9 …”

Section: Resultsmentioning

confidence: 99%

Section: à3mentioning

confidence: 99%

Reduction of structural defects in thick 4H-SiC epitaxial layers grown on 4° off-axis substrates

Yazdanfar

Ivanov

Pedersen

et al. 2013

Journal of Applied Physics

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“…Most of the BPDs in the substrate convert into relatively benign threading edge dislocations (TEDs) during the epitaxial growth. 9,10 The rest of the BPDs propagate into the epilayer. Under device current stress, the BPDs in the active layer act as nucleation sites of Shockley staking faults causing increase of forward voltage drift.…”

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confidence: 99%

“…9,10 It has been reported that the BPD to TED conversion * Electrochemical Society Student Member. z E-mail: songha@cec.sc.edu ratio is higher in the case of growth on 4…”

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confidence: 99%

Study of Surface Morphology, Impurity Incorporation and Defect Generation during Homoepitaxial Growth of 4H-SiC Using Dichlorosilane

Song

Chandrashekhar

Sudarshan

2014

ECS J. Solid State Sci. Technol.

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The growth of 4 • off-axis 4H-SiC epilayers by chemical vapor deposition is studied using dichlorosilane as the Si precursor in a chimney reactor. The unintentional and intentional nitrogen doping at various C/Si ratios and N 2 flow rates are investigated. The C/Si ratio has a significant influence on the growth rate, surface morphology, conversion of basal plane dislocations (BPDs), and generation of other defects (e.g., in-growth stacking faults and morphological defects). Addition of N 2 has no obvious influence on growth rate and BPD conversion. It is preferable to grow high quality n + epilayers at a C/Si ratio in the range of 1.3-1.8 along with the addition of a suitable amount of N 2 in consideration of high growth rate, good surface morphology, and low defect density. In this case, the conversion ratio of BPDs to threading edge dislocations is greater than 99.8% regardless of N 2 addition. Therefore >99.8% substrate BPDs can be buried in an n + buffer layer, which is beneficial to SiC bipolar power devices. No special treatment prior to, during or after the epigrowth is necessary. The epilayers with doping concentration all the way from p − (∼1e15 cm −3 ) to semi-insulating, then to n + (∼1e18 cm −3 ), can be achieved, giving a great range of flexibility in growth using dichlorosilane precursor. Further optimization of in-situ etching and growth conditions to eliminate step bunching has also been suggested. 4H-silicon carbide (4H-SiC) is a promising wide bandgap material for high power electronic devices, owing to its unique thermal and electrical properties such as high breakdown field, high thermal conductivity, and high electron saturation velocity.1,2 Chemical vapor deposition (CVD) is a well-developed technique adopted in semiconductor industry to produce high purity and high quality thin films.3 Homoepitaxial growth of SiC via the CVD technique is one of the key steps in the fabrication of high performance SiC devices. Currently, chloride-based CVD has attracted much interest to potentially replace the traditional silane based CVD for SiC epitaxial growth to reduce the Si droplet formation at high growth rates, because of the higher bonding energy of Si-Cl (400 kJ/mol) than SiSi (226 kJ/mol).4 Dichlorosilane (SiH 2 Cl 2 , DCS) is a gas (boiling point: 8.2• C) at room temperature. It has been demonstrated that using DCS and propane (C 3 H 8 ) as the precursors, high crystalline quality 8• off-axis SiC epilayers were achieved at a high growth rate (up to 100 μm/h). 5,6 At present, the standard off-axis angle of commercially available SiC substrates is lowered to 4• to reduce the material loss during substrate preparation from the crystal boules.Step-bunching is a typical surface feature of the epilayers grown on 4• off-axis substrates, resulting in increase in surface roughness. 7Morphological defects, specifically the triangular defects and inverted pyramids, are prone to be generated in epigrowth on low off-axis angle substrates. 8 Hence, determination of optimized growth conditions to produce SiC ...

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“…The densities of BPD, TED and TSD were not found to be dependent on the growth rate. It has previously been reported for the non-chlorinated growth chemistry that the BPD density can both increase [4] and decrease [13] with increase in growth rate.…”

Section: Resultsmentioning

confidence: 99%

Effect of Process Parameters on Dislocation Density in Thick 4H-SiC Epitaxial Layers Grown by Chloride-Based CVD on 4° Off-Axis Substrates

Yazdanfar

Pedersen

Kordina

et al. 2014

MSF

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Influence of growth conditions on basal plane dislocation in 4H-SiC epitaxial layer

Cited by 101 publications

References 14 publications

Reduction of structural defects in thick 4H-SiC epitaxial layers grown on 4° off-axis substrates

Reduction of structural defects in thick 4H-SiC epitaxial layers grown on 4° off-axis substrates

Study of Surface Morphology, Impurity Incorporation and Defect Generation during Homoepitaxial Growth of 4H-SiC Using Dichlorosilane

Effect of Process Parameters on Dislocation Density in Thick 4H-SiC Epitaxial Layers Grown by Chloride-Based CVD on 4° Off-Axis Substrates

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