摘要:
A gallium nitride-based semiconductor optical device is provided that includes an indium-containing gallium nitride-based semiconductor layer that exhibit low piezoelectric effect and high crystal quality. The gallium nitride-based semiconductor optical device 11a includes a GaN support base 13, a GaN-based semiconductor region 15, and well layers 19. A primary surface 13a tilts from a surface orthogonal to a reference axis that extends in a direction from one crystal axis of the m-axis and the a-axis of GaN toward the other crystal axis. The tilt angle AOFF is 0.05 degree or more to less than 15 degrees. The angle AOFF is equal to the angle defined by a vector VM and a vector VN. The inclination of the primary surface is shown by a typical m-plane SM and m-axis vector VM. The GaN-based semiconductor region 15 is provided on the primary surface 13a. In the well layers 19 in an active layer 17, both the m-plane and the a-plane of the well layers 19 tilt from a normal axis AN of the primary surface 13a. The indium content of the well layers 19 is 0.1 or more.
摘要:
A group III nitride semiconductor optical device 11a has a group III nitride semiconductor substrate 13 having a main surface 13a forming a finite angle with a reference plane Sc orthogonal to a reference axis Cx extending in a c-axis direction of the group III nitride semiconductor and an active layer 17 of a quantum-well structure, disposed on the main surface 13a of the group III nitride semiconductor substrate 13, including a well layer 28 made of a group III nitride semiconductor and a plurality of barrier layers 29 made of a group III nitride semiconductor. The main surface 13a exhibits semipolarity. The active layer 17 has an oxygen content of at least 1×1017 cm−3 but not exceeding 8×1017 cm−3. The plurality of barrier layers 29 contain an n-type impurity other than oxygen by at least 1×1017 cm−3 but not exceeding 1×1019 cm−3 in an upper near-interface area 29u in contact with a lower interface 28Sd of the well layer 28 on the group III nitride semiconductor substrate side.
摘要:
A III-nitride semiconductor device has a support base comprised of a III-nitride semiconductor and having a primary surface extending along a first reference plane perpendicular to a reference axis inclined at a predetermined angle with respect to a c-axis of the III-nitride semiconductor, and an epitaxial semiconductor region provided on the primary surface of the support base. The epitaxial semiconductor region includes GaN-based semiconductor layers. The reference axis is inclined at a first angle from the c-axis of the III-nitride semiconductor toward a first crystal axis, either the m-axis or a-axis. The reference axis is inclined at a second angle from the c-axis of the III-nitride semiconductor toward a second crystal axis, the other of the m-axis and a-axis. Morphology of an outermost surface of the epitaxial semiconductor region includes a plurality of pits. A pit density of the pits is not more than 5×104 cm−2.
摘要:
Provided is a III-nitride semiconductor laser diode which is capable of lasing at a low threshold. A support base has a semipolar or nonpolar primary surface. The c-axis Cx of a III-nitride is inclined relative to the primary surface. An n-type cladding region and a p-type cladding region are provided above the primary surface of the support base. A core semiconductor region is provided between the n-type cladding region and the p-type cladding region. The core semiconductor region includes a first optical guide layer, an active layer, and a second optical guide layer. The active layer is provided between the first optical guide layer and the second optical guide layer. The thickness of the core semiconductor region is not less than 0.5 μm. This structure allows the confinement of light into the core semiconductor region without leakage of light into the support base, and therefore enables reduction in threshold current.
摘要:
Provided is a group-III nitride semiconductor laser device with a laser cavity allowing for a low threshold current, on a semipolar surface of a support base in which the c-axis of a hexagonal group-III nitride is tilted toward the m-axis. First and second fractured faces 27, 29 to form the laser cavity intersect with an m-n plane. The group-III nitride semiconductor laser device 11 has a laser waveguide extending in a direction of an intersecting line between the m-n plane and the semipolar surface 17a. For this reason, it is feasible to make use of emission by a band transition enabling the low threshold current. In a laser structure 13, a first surface 13a is opposite to a second surface 13b. The first and second fractured faces 27, 29 extend from an edge 13c of the first surface 13a to an edge 13d of the second surface 13b. The fractured faces are not formed by dry etching and are different from conventionally-employed cleaved facets such as c-planes, m-planes, or a-planes.
摘要:
A nitride-based semiconductor light-emitting element LE1 or LD1 has: a gallium nitride substrate 11 having a principal surface 11a which makes an angle α, in the range 40° to 50° or in the range more than 90° to 130°, with the reference plane Sc perpendicular to the reference axis Cx extending in the c axis direction; an n-type gallium nitride-based semiconductor layer 13; a second gallium nitride-based semiconductor layer 17; and a light-emitting layer 15 including a plurality of well layers of InGaN and a plurality of barrier layers 23 of a GaN-based semiconductor, wherein the direction of piezoelectric polarization of the plurality of well layers 21 is the direction from the n-type gallium nitride-based semiconductor layer 13 toward the second gallium nitride-based semiconductor layer 17.
摘要:
A group-III nitride semiconductor laser device comprises a laser structure including a support base and a semiconductor region, and an electrode provided on the semiconductor region of the laser structure. The support base comprises a hexagonal group-III nitride semiconductor and has a semipolar primary surface, and the semiconductor region is provided on the semipolar primary surface of the support base. The semiconductor region includes a first cladding layer of a first conductivity type gallium nitride-based semiconductor, a second cladding layer of a second conductivity type gallium nitride-based semiconductor, and an active layer. The first cladding layer, the second cladding layer, and the active layer are arranged along a normal axis to the semipolar primary surface. The active layer comprises a gallium nitride-based semiconductor layer. The c-axis of the hexagonal group-III nitride semiconductor of the support base tilts at a finite angle ALPHA with respect to a normal axis toward an a-axis of the hexagonal group-III nitride semiconductor. The laser structure includes first and second fractured faces intersecting with an a-n plane defined by the normal axis and the a-axis of the hexagonal group-III nitride semiconductor. The laser cavity of the group-III nitride semiconductor laser device includes the first and second fractured faces. The laser structure includes first and second surfaces and the first surface is opposite to the second surface, and each of the first and second fractured faces extends from an edge of the first surface to an edge of the second surface.
摘要:
Provided is a III-nitride semiconductor laser diode capable of lasing to emit light of not less than 500 nm with use of a semipolar plane. Since an active layer 29 is provided so as to generate light at the wavelength of not less than 500 nm, the wavelength of light to be confined into a core semiconductor region 19 is a long wavelength. A first optical guide layer 27 is provided with a two-layer structure, and a second optical guide layer 31 is provided with a two-layer structure. A material of a cladding layer 21 comprised of at least either of AlGaN and InAlGaN is different from the III-nitride semiconductor, and the thickness D15 of a first epitaxial semiconductor region 15 is larger than the thickness D19 of the core semiconductor region 19; however, the misfit dislocation densities at first to third interfaces J1, J2 and J3 are not more than 1×106 cm−1, thereby preventing lattice relaxation from occurring in the semiconductor layers at these interfaces J1, J2 and J3 because of the c-plane that acts as a slip plane.
摘要:
A III-nitride semiconductor device has a support base comprised of a III-nitride semiconductor and having a primary surface extending along a first reference plane perpendicular to a reference axis inclined at a predetermined angle ALPHA with respect to the c-axis of the III-nitride semiconductor, and an epitaxial semiconductor region provided on the primary surface of the support base. The epitaxial semiconductor region includes a plurality of GaN-based semiconductor layers. The reference axis is inclined at a first angle ALPHA1 in the range of not less than 10 degrees, and less than 80 degrees from the c-axis of the III-nitride semiconductor toward a first crystal axis, either one of the m-axis and a-axis. The reference axis is inclined at a second angle ALPHA2 in the range of not less than −0.30 degrees and not more than +0.30 degrees from the c-axis of the III-nitride semiconductor toward a second crystal axis, the other of the m-axis and a-axis. The predetermined angle, the first angle, and the second angle have a relation of ALPHA=(ALPHA12+ALPHA22)1/2. Morphology of an outermost surface of the epitaxial semiconductor region includes a plurality of pits. A pit density of the pits is not more than 5×104 cm−2.
摘要:
In the method of fabricating a nitride-based semiconductor optical device by metal-organic chemical vapor deposition, a barrier layer is grown at a first temperature while supplying a gallium source to a reactor. The barrier layer comprises a first gallium nitride-based semiconductor. After the growth of the barrier layer, a nitrogen material and an indium material are supplied to the reactor without supply of the gallium source to perform a preflow of indium. Immediately after the preflow, a well layer is grown on the barrier layer at a second temperature while supplying an indium source and the gallium source to the reactor. The well layer comprises InGaN, and the second temperature is lower than the first temperature. The gallium source and the indium source are supplied to the reactor during plural first periods of the step of growing the well layer to grow plural InGaN layers, respectively. The indium material is supplied to the reactor without supply of the gallium source during the second period of the step of growing the well layer. The second period is between the first periods. The well layer comprises the plural InGaN layers.