High growth rate 4H-SiC epitaxial growth using dichlorosilane in a hot-wall CVD reactor

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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“…5,6 At present, the standard off-axis angle of commercially available SiC substrates is lowered to 4…”

mentioning

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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“…Basically, a typical CVD system consists of the following parts: 1) sources and feed lines of gases; 2) mass flow controllers for metering the gas inlet; 3) a reaction chamber for decomposition of precursor gases; 4) a system for heating up the gas phase and wafer on which the film is to be deposited; and 5) temperature sensors. Concerning the gas chemistry of CVD process for SiC film production, usually silane (SiH 4 ) and light hydrocarbons gases are used, such as propane or ethylene, diluted in hydrogen as a carrier gas (Chowdhury et al, 2011). Moreover, the main CVD reactor types used are atmospheric pressure CVD (APCVD) and low-pressure CVD (LPCVD).…”

Section: Chemical Deposition Processes: Cvd and Pecvd Techniquesmentioning

confidence: 99%

Recent Developments on Silicon Carbide Thin Films for Piezoresistive Sensors Applications

Fraga¹,

Pessoa²,

Maciel³

et al. 2011

Silicon Carbide - Materials, Processing and Applications in Electronic Devices

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“…The easiest, cost effective and relatively low temperature techniques of depositing SiC based coating on any substrate are chemical vapour deposition (CVD) and physical vapour deposition (PVD) [12][13][14][15][16][17] by injection of inorganic salts, organic silane or feed gases like CH 4 , H 2 etc. Applications of wear resistant coatings of SiC on high temperature alloys for enhancement of wear resistance have been reported [18,19].…”

Section: Introductionmentioning

confidence: 99%

Mechanical and tribological properties of silicon carbide coating on Inconel alloy from liquid pre-ceramic precursor

Mukherjee

Chakraborty

Chakravarty

et al. 2014

Ceramics International

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High growth rate 4H-SiC epitaxial growth using dichlorosilane in a hot-wall CVD reactor

Cited by 45 publications

References 36 publications

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

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

Recent Developments on Silicon Carbide Thin Films for Piezoresistive Sensors Applications

Mechanical and tribological properties of silicon carbide coating on Inconel alloy from liquid pre-ceramic precursor

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