Cubic Silicon Carbide (3C-SiC) approaches quality of commercial hexagonal SiC
In short: Cubic silicon carbide (3C-SiC) is an attractive material for a number of semiconductor applications. However, due to its metastable nature, it is very challenging to grow with a crystalline quality similar to the one obtained in commercially available hexagonal SiC substrates. We introduce a novel approach to grow high crystalline quality 3C-SiC in a reproducible and controllable way. Thick (up to 1 mm) 3C-SiC layers grown using our approach could be used as seeding layers in bulk growth or in homoepitaxial growth for fabricating various device structures.
The 3C-SiC has unique material properties which can be used in designing and fabricating a new range of advanced semiconductor applications. However, the lack of high quality 3C-SiC substrates is hindering the progress in exploring these applications. To date, it has been challenging to produce high crystalline quality 3C-SiC substrates since the 3C-SiC is metastable and it can easily transform to another polytype during the growth process. Moreover, a heteropeitaxial growth of 3C-SiC on foreign substrates, e.g. silicon or nominally on-axis hexagonal SiC, brings additional challenges. A large mismatch in lattice parameter and thermal expansion coefficient between the silicon and 3C-SiC leads to the formation of a high density of structural defects in the grown material. Such mismatch is negligible if a hexagonal SiC is used as a substrate. However, the 3C-SiC domains can nucleate in two equally possible orientations rotated by 60° on (0001) plane and form special defects called double positioning boundaries (DPBs).
We present a novel 3C-SiC growth approach and demonstrate that high crystalline quality 3C-SiC layers with significantly reduced density of DPBs can be grown on off-oriented hexagonal SiC substrates. Our 3C-SiC growth process is based on three interconnected stages: I) in situ formation of a large terrace at the edge of 4H-SiC substrate, II) formation of the 3C-SiC domains on this terrace and III) merging and lateral enlargement of the 3C-SiC domains in the off-axis direction. Using this generic approach, which may be applied by other growth techniques, we have obtained high crystalline quality 3C-SiC up to a layer thickness of 1 mm.
Details of the research are described in Crystal Growth & Design 14, 6514 (2014) doi:10.1021/cg501424e
Valdas Jokubavicius, PhD student
Phone: +46 (0)13 28 26 41
- Swedish Energy Agency
- Swedish Governmental Agency for Innovation Systems (Vinnova)
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Last updated: 03/31/15