Abstract:
A metal film is deposited on a starting substrate, which is any one of a single crystal sapphire substrate, a substrate comprising a single crystal gallium nitride film grown on a sapphire substrate, and a single crystal semiconductor substrate, and a gallium nitride film is deposited on the metal film to form a laminate substrate. By virtue of the above construction, after the growth of the gallium nitride film, the gallium nitride film can be easily separated from the starting substrate, and a gallium nitride crystal substrate, which has low defect density and has not been significantly contaminated with impurities, can be produced in a simple manner.
Abstract:
A group III-V nitride-based semiconductor substrate is formed of a group III-V nitride-based semiconductor single crystal containing an n-type impurity. The single crystal has a periodical change in concentration of the n-type impurity in a thickness direction of the substrate. The periodical change has a minimum value in concentration of the n-type impurity not less than 5×1017 cm−3 at an arbitrary point in plane of the substrate.
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.
Abstract:
A III group nitride semiconductor substrate according to the present invention is fabricated by forming a metal film or metal nitride film 2′ with mesh structure in which micro voids are provided on a starting substrate 1, and growing a III group nitride semiconductor crystal layer 3 via the metal film or metal nitride film 2′.
Abstract:
A III-V group nitride system semiconductor substrate is of a III-V group nitride system single crystal. The III-V group nitride system semiconductor substrate has a flat surface, and a vector made by projecting on a surface of the substrate a normal vector of a low index surface closest to the substrate surface at an arbitrary point in a plane of the substrate is converged on a specific point or a specific region inside or outside the plane of the substrate.
Abstract:
A III-V group nitride system semiconductor self-standing substrate is made of III-V group nitride system semiconductor single crystal with a hexagonal crystal system crystalline structure. The substrate is provided with a surface that is off-oriented 0.09 degrees or more and 24 degrees or less in the a-axis or m-axis direction from C-face of the substrate.
Abstract:
A III–V group nitride system semiconductor self-standing substrate has: a first III–V group nitride system semiconductor crystal layer that has a region with dislocation lines gathered densely, the dislocation lines being gathered substantially perpendicular to a surface of the substrate, and a region with dislocation lines gathered thinly; and a second III–V group nitride system semiconductor crystal layer that is formed up to 10 μm from the surface of the substrate on the first III–V group nitride system semiconductor crystal layer and that has a dislocation density distribution that is substantially uniform.
Abstract:
A group III-V nitride-based semiconductor substrate having a group III-V nitride-based semiconductor thick film with a same composition in the entire film. The thick film has a first region with a predetermined impurity concentration and a second region with an impurity concentration lower than the first region.
Abstract:
A III–V group nitride system semiconductor substrate has III–V group nitride system single crystal grown on a hetero-substrate. The III–V group nitride system semiconductor substrate has a flat surface and satisfies the relationship of θ>α, where θ [deg ] is given as an average in angles of the substrate surface to low index surfaces closest to the substrate surface measured at a plurality of arbitrary points in plane of the substrate, and a variation range of the measured angles to θ is represented by ±α [deg ].
Abstract:
A III–V nitride semiconductor substrate comprising a III–V nitride semiconductor single crystal at least in a surface portion thereof, the product of [H] and [D] being 1×1025 or less, wherein [H] represents the concentration of hydrogen atoms (the number of hydrogen atoms per cm3) in a surface portion of the single crystal, and [D] represents a dislocation density (the number of dislocations per cm2) on a single crystal surface.