AlxInyGa1-x-yN MIXTURE CRYSTAL SUBSTRATE, METHOD OF GROWING SAME AND METHOD OF PRODUCING SAME

A method of growing an AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) mixture crystal substrate comprising the steps of:

• making pits composed of facets with bottoms on an AlxInyGa1-x-yN growing surface;
• producing closed defect accumulating regions (H) at the bottoms of the facet pits;
• attracting, annihilating and accumulating dislocations in surrounding regions by the closed defect accumulating regions (H);
• and
• reducing the dislocations of the surrounding regions.

A method of growing an AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) mixture crystal substrate comprising the steps of:

• implanting seeds on an undersubstrate;
• growing an AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) crystal on the undersubstrate in vapor phase on a condition of producing facet pits;
• forming pits composed of facets on the growing AlxInyGa1-x-yN crystal above the implanted seeds;
• making closed defect accumulating regions (H) following bottoms of the facet pits and consisting of cores (S) having converged dislocations and extending perpendicular to the undersubstrate and grain boundaries (K) enclosing the cores (S);
• making accompanying low dislocation single crystal regions (Z) surrounding the closed defect accumulating regions (H) under the pit facets;
• making extra low dislocation single crystal regions (Y) around the accompanying low dislocation single crystal regions (Z) under a C-plane growing surface outside of the facet pits;
• utilizing solely the grain boundaries (K) or both the grain boundaries (K) and the cores (S) enclosed by the grain boundaries (K) as dislocation annihilation/accumulation regions;
• gathering dislocations by the facet pits from the accompanying low dislocation single crystal regions (Z) and the extra low dislocation single crystal regions (Y) to the closed defect accumulating regions (H);
• annihilating and accumulating the dislocations in the boundaries (K) or in the boundaries (K) and the cores (S) of the closed defect accumulating regions (H);
• reducing dislocations in the accompanying low dislocation single crystal regions (Z) and the extra low dislocation single crystal regions (Y);
• and
• obtaining a low dislocation AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) crystal.

The method of producing an AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) mixture crystal substrate comprising the steps of:

• implanting seeds on an undersubstrate;
• growing an AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) crystal on the undersubstrate in vapor phase on a condition of producing facet pits;
• forming pits composed of facets on the growing AlxInyGa1-x-yN crystal above the implanted seeds;
• making closed defect accumulating regions (H) following bottoms of the facet pits and consisting of cores (S) having converged dislocations and extending perpendicular to the undersubstrate and grain boundaries (K) enclosing the cores (S);
• making accompanying low dislocation single crystal regions (Z) surrounding the closed defect accumulating regions (H) under the pit facets;
• making extra low dislocation single crystal regions (Y) around the accompanying low dislocation single crystal regions (Z) under a C-plane growing surface outside of the facet pits;
• utilizing solely the grain boundaries (K) or both the grain boundaries (K) and the cores (S) enclosed by the grain boundaries (K) as dislocation annihilation/accumulation regions;
• gathering dislocations by the facet pits from the accompanying low dislocation single crystal regions (Z) and the extra low dislocation single crystal regions (Y) to the closed defect accumulating regions (H);
• annihilating and accumulating the dislocations in the boundaries (K) or in the boundaries (K) and the cores (S) of the closed defect accumulating regions (H);
• reducing dislocations in the accompanying low dislocation single crystal regions (Z) and the extra low dislocation single crystal regions (Y);
• obtaining a low dislocation AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) crystal;
• slicing, grinding, lapping or other mechanical processing the low dislocation AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) crystal for making a uniform AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) substrate without facets and undersubstrate;
• polishing the uniform AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) substrate;
• and
• obtaining a flat, smooth AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) substrate.

The method of producing an AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) substrate comprising the steps of:

• preparing an undersubstrate which is a single crystal AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) substrate including a plurality of fundamental units (Q),
• the fundamental unit (Q) containing;
• a closed defect accumulating region (H) including a core (S) extending vertical to surfaces of the undersubstrate and containing many accumulated defects and a grain boundary (K) enclosing the core (S),
• an accompanying low dislocation single crystal region (Z) surrounding the closed defect accumulating region (H) and being a single crystal of a basic orientation with low dislocation density, and
• an extra low dislocation single crystal region (Y) lying outside of the accompanying low dislocation single crystal region (Z) and being a single crystal with the same basic orientation as the accompanying low dislocation single crystal region (Z);
• growing an AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) crystal on the AlxInyGa1-x-yN undersubstrate in vapor phase on a condition of producing facet pits;
• forming pits composed of facets on the growing AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) crystal just above the closed defect accumulating regions (H) and the accompanying low dislocation single crystal regions (Z) of the AlxInyGa1-x-yN undersubstrate;
• making closed defect accumulating regions (H) following bottoms of the facet pits and succeeding the closed defect accumulating regions (H) of the AlxInyGa1-x-yN undersubstrate, the closed defect accumulating regions (H) consisting of a core (S) having converged dislocations and extending perpendicular to the undersubstrate and grain boundary (K) enclosing the core (S);
• making accompanying low dislocation single crystal regions (Z) surrounding the closed defect accumulating regions (H) under the pit facets and on the accompanying low dislocation single crystal regions (Z) of the AlxInyGa1-x-yN undersubstrate;
• making extra low dislocation single crystal regions (Y) around the accompanying low dislocation single crystal regions (Z) under a C-plane growing surface outside of the facet pits and on the extra low dislocation single crystal regions (Y) of the AlxInyGa1-x-yN undersubstrate;
• utilizing solely the grain boundaries (K) or both the grain boundaries (K) and the cores (S) enclosed by the grain boundaries (K) as dislocation annihilation/accumulation regions;
• gathering dislocations by the facet pits from the accompanying low dislocation single crystal regions (Z) and the extra low dislocation single crystal regions (Y) to the closed defect accumulating regions (H);
• annihilating and accumulating the dislocations in the boundaries (K) or in the boundaries (K) and the cores (S) of the closed defect accumulating regions (H);
• reducing dislocations in the accompanying low dislocation single crystal regions (Z) and the extra low dislocation single crystal regions (Y);
• obtaining a low dislocation AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) crystal;
• slicing, grinding, lapping or other mechanical processing the low dislocation AlxInyGa1-x-yN crystal for making a uniform AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) substrate without facets and undersubstrate;
• polishing the uniform AlxInyGa1-x-yN substrate;
• and
• obtaining a flat, smooth AlxInyGa1-x-yN (0≦x≦1, 0≦y≦1, 0<x+y≦1) substrate.