Porous substrate and its manufacturing method, and gan semiconductor multilayer substrate and its manufacturing method
First Claim
1. A porous substrate, comprising a plurality of porous layers thereon, wherein the average opening diameter of pores in a porous layer of said plurality of porous layers positioned in an outermost surface is smaller than the average diameter of pores in a porous layer of said plurality of porous layers positioned on a substrate side relative to said porous layer positioned in said outermost surface.
5 Assignments
0 Petitions
Accused Products
Abstract
A structure of a substrate used for growing a crystal layer of a semiconductor, particularly a group-III nitride semiconductor and its manufacturing method. The substrate comprises two porous layers on a base. The mean opening diameter of the pores of the first porous laser, the outermost layer, is smaller than the means diameter of the pores in the second porous layer nearer to the base than the first porous layer. The first and second porous layers have volume porosities of 10 to 90%. More then 50% of the pores of the first porous layer extend from the surface of the first porous layer and reach the interface between the first and second porous layers. Even by a conventional crystal growing method, an epitaxial crystal of low defect density can be easily grown on the porous substrate.
36 Citations
17 Claims
- 1. A porous substrate, comprising a plurality of porous layers thereon, wherein the average opening diameter of pores in a porous layer of said plurality of porous layers positioned in an outermost surface is smaller than the average diameter of pores in a porous layer of said plurality of porous layers positioned on a substrate side relative to said porous layer positioned in said outermost surface.
-
2. A porous substrate, comprising a plurality of porous layers thereon, wherein the average opening diameter of pores in a porous layer of said plurality of porous layers positioned in an outermost surface is smaller than the average diameter of pores in a porous layer of said plurality of porous layers positioned on a substrate side relative to said porous layer positioned in said outermost surface;
- and the volume porosity of said plurality of porous layers is 10%-90%.
- View Dependent Claims (15)
-
3. A porous substrate, comprising two porous layers thereon, wherein the average opening diameter of pores in a first porous layer of said two porous layers positioned in an outermost surface is smaller than the average diameter of pores in a second porous layer positioned on a substrate side relative to said first porous layer;
- and more than 50% of said pores in said first porous layer penetrate from the surface of said first porous layer to the interface between said first and second porous layer.
- View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 16)
-
4. A porous substrate, comprising two porous layers thereon, wherein the average opening diameter of pores in a first porous layer of said two porous layers positioned in an outermost surface is smaller than the average diameter of pores in a second porous layer positioned on a substrate side relative to said first porous layer;
- more than 50% of said pores in said first porous layer penetrate from the surface of said first porous layer to the interface between said first and second porous layer; and
the volume porosity of said first and second porous layer is 10%-90%. - View Dependent Claims (17)
- more than 50% of said pores in said first porous layer penetrate from the surface of said first porous layer to the interface between said first and second porous layer; and
-
12. A fabrication method for a porous substrate, comprising growing two or more different material layers on a substrate, heating said each layer, and thereby forming two or more porous layers with pores therein.
-
14. A fabrication method for a GaN series semiconductor layered substrate, comprising growing two or more different material layers on a substrate, heating said each layer, thereby forming a porous substrate with two or more porous layers having pores therein, and growing a GaN semiconductor layer on that porous substrate.
Specification