Abstract: A first Group III nitride compound semiconductor layer 31 is etched, to thereby form an island-like structure such as a dot-like, stripe-shaped, or grid-like structure, so as to provide a trench/post. Thus, a second Group III nitride compound layer 32 can be epitaxially grown, vertically and laterally, from a top surface of the post and a sidewall/sidewalls of the trench serving as a nucleus for epitaxial growth, to thereby bury the trench and also grow the layer in the vertical direction. In this case, propagation of threading dislocations contained in the first Group III nitride compound semiconductor layer 31 can be prevented in the upper portion of the second Group III nitride compound semiconductor 32 that is formed through lateral epitaxial growth. As a result, a region having less threading dislocations is formed at the buried trench.

Abstract: The present invention provides a Group III nitride compound semiconductor with suppressed generation of threading dislocations. A GaN layer 31 is subjected to etching, so as to form an island-like structure having a shape of, for example, dot, stripe, or grid, thereby providing a trench/mesa structure, and a mask 4 is formed at the bottom of the trench such that the upper surface of the mask 4 is positioned below the top surface of the GaN layer 31. A GaN layer 32 is lateral-epitaxially grown with the top surface 31a of the mesa and sidewalls 31b of the trench serving as nuclei, to thereby bury the trench, and then epitaxial growth is effected in the vertical direction. In the upper region of the GaN layer 32 formed above the mask 4 through lateral epitaxial growth, propagation of threading dislocations contained in the GaN layer 31 can be prevented.

Abstract: A sapphire substrate 1 is etched so that each trench has a width of 10 ?m and a depth of 10 ?m were formed at 10 ?m of intervals in a stripe pattern. Next, an AlN buffer layer 2 having a thickness of approximately 40 nm is formed mainly on the upper surface and the bottom surface of the trenches of the substrate 1. Then a GaN layer 3 is formed through vertical and lateral epitaxial growth. At this time, lateral epitaxial growth of the buffer layer 21, which was mainly formed on the upper surface of the trenches, filled the trenches and thus establishing a flat top surface. The portions of the GaN layer 3 formed above the top surfaces of the mesas having a depth of 10 ?m exhibited significant suppression of threading dislocation in contrast to the portions formed above the bottoms of the trenches.

Abstract: A first Group III nitride compound semiconductor layer 31 is etched, to thereby form an island-like structure such as a dot-like, stripe-shaped, or grid-like structure, so as to provide a trench/mesa such that layer different from the first Group III nitride compound semiconductor layer 31 is exposed at the bottom portion of the trench. Thus, a second Group III nitride compound layer 32 can be epitaxially grown, laterally, with a top surface of the mesa and a sidewall/sidewalls of the trench serving as a nucleus, to thereby bury the trench and also grow the layer in the vertical direction. In this case, propagation of threading dislocations contained in the first Group III nitride compound semiconductor layer 31 can be prevented in the upper portion of the second Group III nitride compound semiconductor 32 that is formed through lateral epitaxial growth. Etching may be performed until a cavity portion is provided in the substrate.

Abstract: When a substrate layer (desired semiconductor crystal) made of a group III nitride compound is grown on a base substrate comprising a lot of projection parts, a cavity in which a semiconductor crystal is not deposited may be formed between each projection part although it depends on conditions such as the size of each projection part, arranging interval between each projection part and crystal growth. So when the thickness of the substrate layer is sufficiently larger compared with the height of the projection part, inner stress or outer stress become easier to act intensively to the projection part. As a result, such stress especially functions as shearing stress toward the projection part. When the shearing stress becomes larger, the projection part is ruptured. So utilizing the shearing stress enables to separate the base substrate and the substrate layer easily.

Abstract: A sapphire substrate 1 is etched so that each trench has a width of 10 ?m and a depth of 10 ?m were formed at 10 ?m of intervals in a stripe pattern. Next, an AlN buffer layer 2 having a thickness of approximately 40 nm is formed mainly on the upper surface and the bottom surface of the trenches of the substrate 1. Then a GaN layer 3 is formed through vertical and lateral epitaxial growth. At this time, lateral epitaxial growth of the buffer layer 21, which was mainly formed on the upper surface of the trenches, filled the trenches and thus establishing a flat top surface. The portions of the GaN layer 3 formed above the top surfaces of the mesas having a depth of 10 ?m exhibited significant suppression of threading dislocation in contrast to the portions formed above the bottoms of the trenches.

Abstract: A first Group III nitride compound semiconductor layer 31 is etched, to thereby form an island-like structure such as a dot-like, stripe-shaped, or grid-like structure, so as to provide a trench/post. Thus, a second Group III nitride compound layer 32 can be epitaxially grown, vertically and laterally, from a top surface of the post and a sidewall/sidewalls of the trench serving as a nucleus for epitaxial growth, to thereby bury the trench and also grow the layer in the vertical direction. In this case, propagation of threading dislocations contained in the first Group III nitride compound semiconductor layer 31 can be prevented in the upper portion of the second Group III nitride compound semiconductor 32 that is formed through lateral epitaxial growth. As a result, a region having less threading dislocations is formed at the buried trench.

Abstract: A first Group III nitride compound semiconductor layer 31 is etched, to thereby form an island-like structure such as a dot-like, stripe-shaped, or grid-like structure, so as to provide a trench/post. Thus, a second Group III nitride compound layer 32 can be epitaxially grown, vertically and laterally, from a top surface of the post and a sidewall/sidewalls of the trench serving as a nucleus for epitaxial growth, to thereby bury the trench and also grow the layer in the vertical direction. In this case, propagation of threading dislocations contained in the first Group III nitride compound semiconductor layer 31 can be prevented in the upper portion of the second Group III nitride compound semiconductor 32 that is formed through lateral epitaxial growth. As a result, a region having less threading dislocations is formed at the buried trench.

Abstract: A sapphire substrate 1 is etched so that each trench has a width of 10 ?m and a depth of 10 ?m were formed at 10 ?m of intervals in a stripe pattern. Next, an AlN buffer layer 2 having a thickness of approximately 40 nm is formed mainly on the upper surface and the bottom surface of the trenches of the substrate 1. Then a GaN layer 3 is formed through vertical and lateral epitaxial growth. At this time, lateral epitaxial growth of the buffer layer 21, which was mainly formed on the upper surface of the trenches, filled the trenches and thus establishing a flat top surface. The portions of the GaN layer 3 formed above the top surfaces of the mesas having a depth of 10 ?m exhibited significant suppression of threading dislocation in contrast to the portions formed above the bottoms of the trenches.

Abstract: The present invention provides a Group III nitride compound semiconductor with suppressed generation of threading dislocations. A GaN layer 31 is subjected to etching, so as to form an island-like structure having a shape of, for example, dot, stripe, or grid, thereby providing a trench/mesa structure, and a mask 4 is formed at the bottom of the trench such that the upper surface of the mask 4 is positioned below the top surface of the GaN layer 31. A GaN layer 32 is lateral-epitaxially grown with the top surface 31a of the mesa and sidewalls 31b of the trench serving as nuclei, to thereby bury the trench, and then epitaxial growth is effected in the vertical direction. In the upper region of the GaN layer 32 formed above the mask 4 through lateral epitaxial growth, propagation of threading dislocations contained in the GaN layer 31 can be prevented.

Abstract: The present invention provides a Group III nitride compound semiconductor with suppressed generation of threading dislocations. A GaN layer 31 is subjected to etching, so as to form an island-like structure having a shape of, for example, dot, strip, or grid, thereby providing a trench/mesa structure, and a mask 4 is formed at the bottom of the trench such that the upper surface of the mask 4 is positioned below the top surface of the GaN layer 31. A GaN layer 32 is lateral-epitaxially grown with the top surface 31a of the mesa and sidewalls 31b of the trench serving as nuclei, to thereby bury the trench, and then epitaxial growth is effected in the vertical direction. In the upper region of the GaN layer 32 formed above the mask 4 through lateral epitaxial growth, propagation of threading dislocations contained in the GaN layer is 31 can be prevented.

Abstract: A GaN layer 31 is subjected to etching, so as to form an island-like structure having, for example, a dot, stripe, or grid shape, thereby providing a trench/mesa structure including mesas and trenches whose bottoms sink into the surface of a substrate base 1. Subsequently, a GaN layer 32 is lateral-epitaxially grown with the top surfaces of the mesas and sidewalls of the trenches serving as nuclei, to thereby fill upper portions of the trenches (depressions of the substrate base 1), and then epitaxial growth is effected in the vertical direction. In this case, propagation of threading dislocations contained in the GaN layer 31 can be prevented in the upper portion of the GaN layer 32 that is formed through lateral epitaxial growth.

Abstract: By using a mask 4, a first Group III nitride compound semiconductor layer 31 is etched, to thereby form an island-like structure such as a dot-like, striped-shaped, or grid-like structure, so as to provide a trench/post. Thus, without removing the mask 4 formed on a top surface of the upper layer of the post, a second Group III nitride compound layer 32 can be epitaxially grown, vertically and laterally, with a sidewall/sidewalls of the trench serving as a nucleus, to thereby bury the trench and also grow the layer in the vertical direction. The second Group III nitride compound layer 32 does not grow epitaxially on the mask 4. In this case, propagation of threading dislocations contained in the first Group III nitride compound semiconductor layer 31 can be prevented in the upper portion of the second Group III nitride compound semiconductor 32 that is formed through lateral epitaxial growth and a region having less threading dislocations can be formed in the buried portion of the trench.

Abstract: When a substrate layer (desired semiconductor crystal) made of a group III nitride compound is grown on a base substrate comprising a lot of projection parts, a cavity in which a semiconductor crystal is not deposited may be formed between each projection part although it depends on conditions such as the size of each projection part, arranging interval between each projection part and crystal growth. So when the thickness of the substrate layer is sufficiently larger compared with the height of the projection part, inner stress or outer stress become easier to act intensively to the projection part. As a result, such stress especially functions as shearing stress toward the projection part. When the shearing stress becomes larger, the projection part is ruptured. So utilizing the shearing stress enables to separate the base substrate and the substrate layer easily.

Abstract: A GaN layer 31 is subjected to etching, so as to form an island-like structure having, for example, a dot, stripe, or grid shape, thereby providing a trench/mesa structure including mesas and trenches whose bottoms sink into the surface of a substrate base 1. Subsequently, a GaN layer 32 is lateral-epitaxially grown with the top surfaces of the mesas and sidewalls of the trenches serving as nuclei, to thereby fill upper portions of the trenches (depressions of the substrate base 1), and then epitaxial growth is effected in the vertical direction. In this case, propagation of threading dislocations contained in the GaN layer 31 can be prevented in the upper portion of the GaN layer 32 that is formed through lateral epitaxial growth.

Abstract: A semiconductor laser 101 comprises a sapphire substrate 1, an AlN buffer layer 2, Si-doped GaN n-layer 3, Si-doped Al0.1Ga0.9N n-cladding layer 4, Si-doped GaN n-guide layer 5, an active layer 6 having multiple quantum well (MQW) structure in which about 35 Å in thickness of GaN barrier layer 62 and about 35 Å in thickness of Ga0.95In0.05N well layer 61 are laminated alternately, Mg-doped GaN p-guide layer 7, Mg-doped Al0.1Ga0.9N p-cladding layer 8, and Mg-doped GaN p-contact layer 9 are formed successively thereon. A ridged hole injection part B which contacts to a ridged resonator part A is formed to have the same width as the width w of an Ni electrode 10. Holes transmitted from the Ni electrode 10 are injected to the active layer 6 with high current density, and electric current threshold for laser oscillation can be decreased. Electric current threshold can be improved more effectively by forming also the p-guide layer 7 to have the same width as the width w of the Ni electrode 10.

Abstract: A guide layer is formed to have a superlattice structure comprising five pairs of layers of AlGaN and InN, each having a thickness of about 10 nm. The guide layer has a total thickness of about 0.1 &mgr;m. The guide layer so structured has a reduced elastic constant such that the guide layer acts as a stress relieving layer.

Abstract: A sapphire substrate 1 is etched so that each trench has a width of 10 &mgr;m and a depth of 10 &mgr;m were formed at 10 &mgr;m of intervals in a stripe pattern. Next, an AlN buffer layer 2 having a thickness of approximately 40 nm is formed mainly on the upper surface and the bottom surface of the trenches of the substrate 1. Then a GaN layer 3 is formed through vertical and lateral epitaxial growth. At this time, lateral epitaxial growth of the buffer layer 21, which was mainly formed on the upper surface of the trenches, filled the trenches and thus establishing a flat top surface. The portions of the GaN layer 3 formed above the top surfaces of the mesas having a depth of 10 &mgr;m exhibited significant suppression of threading dislocation in contrast to the portions formed above the bottoms of the trenches.

Abstract: A first Group III nitride compound semiconductor layer 31 is etched, to thereby form an island-like structure such as a dot-like, stripe-shaped, or grid-like structure, so as to provide a trench/mesa such that layer different from the first Group III nitride compound semiconductor layer 31 is exposed at the bottom portion of the trench. Thus, a second Group III nitride compound layer 32 can be epitaxially grown, laterally, with a top surface of the mesa and a sidewall/sidewalls of the trench serving as a nucleus, to thereby bury the trench and also grow the layer in the vertical direction. In this case, propagation of threading dislocations contained in the first Group III nitride compound semiconductor layer 31 can be prevented in the upper portion of the second Group III nitride compound semiconductor 32 that is formed through lateral epitaxial growth. Etching may be performed until a cavity portion is provided in the substrate.

Abstract: The present invention provides a Group III nitride compound semiconductor with suppressed generation of threading dislocations.