SiC semiconductor substrate and fabrication method of the SiC semiconductor substrate

1 . An SiC semiconductor substrate, comprising:

an SiC single crystal substrate having an Si plane;

a first graphene layer formed directly on the Si plane of the SiC single crystal substrate;

an SiC epitaxial layer disposed above the SiC single crystal substrate via the first graphene layer, and having an Si plane; and

a second graphene layer having a first surface formed directly on the Si plane of the SiC epitaxial layer, and a second surface opposed to the first surface and having a flat surface on an entirety of the second surface.

2 . The SiC semiconductor substrate according to claim 1 , further comprising

an SiC polycrystalline substrate that is provisionally bonded to the SiC epitaxial layer via the second graphene layer.

3 . The SiC semiconductor substrate according to claim 1 , wherein

the first graphene layer comprises a single-layer structure or multi-layer laminated structure of graphene.

4 . The SiC semiconductor substrate according to claim 2 , wherein

the first graphene layer comprises a single-layer structure or multi-layer laminated structure of graphene.

5 . The SiC semiconductor substrate according to claim 2 , wherein

the SiC polycrystalline substrate comprises a sintered SiC substrate or a CVD substrate.

6 . The SiC semiconductor substrate according to claim 1 , wherein

the SiC single crystal substrate can be reused by being removed from the SiC epitaxial layer.

7 . The SiC semiconductor substrate according to claim 2 , wherein

the SiC single crystal substrate can be reused by being removed from the SiC epitaxial layer.

8 . The SiC semiconductor substrate according to claim 3 , wherein

the SiC single crystal substrate can be reused by being removed from the SiC epitaxial layer.

9 . The SiC semiconductor substrate according to claim 4 , wherein

the SiC single crystal substrate can be reused by being removed from the SiC epitaxial layer.

10 . The SiC semiconductor substrate according to claim 1 , further comprising

an SiC polycrystalline layer grown by CVD on a C plane of the SiC epitaxial layer, wherein

the SiC epitaxial layer is transferred to the SiC polycrystalline layer.

11 . The SiC semiconductor substrate according to claim 2 , further comprising

an SiC polycrystalline layer grown by CVD on a C plane of the SiC epitaxial layer, wherein

the SiC epitaxial layer is transferred to the SiC polycrystalline layer.

12 . The SiC semiconductor substrate according to claim 3 , further comprising

an SiC polycrystalline layer grown by CVD on a C plane of the SiC epitaxial layer, wherein

the SiC epitaxial layer is transferred to the SiC polycrystalline layer.

13 . The SiC semiconductor substrate according to claim 1 , wherein

the SiC single crystal substrate comprises any one crystal structure selected from a group consisting of 4H—SiC, 6H—SiC, and 2H—SiC crystal structures.

14 . The SiC semiconductor substrate according to claim 10 , further comprising

a doped layer formed between the SiC epitaxial layer and the SiC polycrystalline layer, the doped layer having a higher impurity concentration than that of the SiC epitaxial layer.

15 . A fabrication method of an SiC semiconductor substrate, comprising:

forming a first graphene layer directly on an Si plane of an SiC single crystal substrate serving as a basis;

epitaxially growing a first layer formed of a single-crystal SiC semiconductor via the first graphene layer;

forming a second graphene layer directly on an Si plane of the first layer, the second graphene layer having a first surface formed directly on the Si plane of the first layer, and a second surface opposed to the first surface and having a flat surface on an entirety of the second surface;

forming a polycrystal SiC semiconductor substrate via the second graphene layer;

removing the single crystal substrate serving as the basis from the first graphene layer;

eliminating the first graphene layer to expose a C plane of the first layer;

forming a second layer on the C plane of the first layer by CVD growth;

removing the polycrystal SiC semiconductor substrate; and

eliminating the second graphene layer.

16 . The fabrication method of the SiC semiconductor substrate according to claim 15 , wherein

the epitaxially growing the first layer comprises growing the first layer by remote epitaxy on the single crystal substrate serving as the basis.

17 . The fabrication method of the SiC semiconductor substrate according to claim 15 , wherein

a front side surface of the first layer is an Si plane of [0001] orientation of 4H—SiC, and

a C plane of the first layer is a plane of [000-1] orientation of 4H—SiC.

18 . The fabrication method of the SiC semiconductor substrate according to claim 15 , wherein

the forming of the second layer by the CVD growth comprises forming the second layer formed of a polycrystalline SiC semiconductor.

19 . The fabrication method of the SiC semiconductor substrate according to claim 15 , further comprising, after the exposing of the C plane of the first layer, forming a layer having a higher impurity concentration than that of the first layer on the C plane of the first layer.

20 . The fabrication method of the SiC semiconductor substrate according to claim 15 , wherein

the epitaxially growth of the first layer formed of the single-crystal SiC semiconductor via the first graphene layer comprises forming a layer having a higher impurity concentration than that of the first layer at an initial stage of the epitaxial growth.