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 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 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:
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 a GaN based semiconductor optical device 11a, the primary surface 13a of the substrate 13 tilts at a tilting angle toward an m-axis direction of the first GaN based semiconductor with respect to a reference axis “Cx” extending in a direction of a c-axis of the first GaN based semiconductor, and the tilting angle is 63 degrees or more, and is less than 80 degrees. The GaN based semiconductor epitaxial region 15 is provided on the primary surface 13a. On the GaN based semiconductor epitaxial region 15, an active layer 17 is provided. The active layer 17 includes one semiconductor epitaxial layer 19. The semiconductor epitaxial layer 19 is composed of InGaN. The thickness direction of the semiconductor epitaxial layer 19 tilts with respect to the reference axis “Cx.” The reference axis “Cx” extends in the direction of the [0001] axis. This structure provides the GaN based semiconductor optical device that can reduces decrease in light emission characteristics due to the indium segregation.
摘要:
In the nitride based semiconductor optical device LE1, the strained well layers 21 extend along a reference plane SR1 tilting at a tilt angle α from the plane that is orthogonal to a reference axis extending in the direction of the c-axis. The tilt angle α is in the range of greater than 59 degrees to less than 80 degrees or greater than 150 degrees to less than 180 degrees. A gallium nitride based semiconductor layer P is adjacent to a light-emitting layer SP− with a negative piezoelectric field and has a band gap larger than that of a barrier layer. The direction of the piezoelectric field in the well layer W3 is directed in a direction from the n-type layer to the p-type layer, and the piezoelectric field in the gallium nitride based semiconductor layer P is directed in a direction from the p-type layer to the n-type layer. Consequently, the valence band, not the conduction band, has a dip at the interface between the light-emitting layer SP− and the gallium nitride based semiconductor layer P.
摘要:
Provided is a Group III nitride semiconductor laser diode with a cladding layer capable of providing high optical confinement and carrier confinement. An n-type Al0.08Ga0.92N cladding layer is grown so as to be lattice-relaxed on a (20-21)-plane GaN substrate. A GaN optical guiding layer is grown so as to be lattice-relaxed on the n-type cladding layer. An active layer, a GaN optical guiding layer, an Al0.12Ga0.88N electron blocking layer, and a GaN optical guiding layer are grown so as not to be lattice-relaxed on the optical guiding layer. A p-type Al0.08Ga0.92N cladding layer is grown so as to be lattice-relaxed on the optical guiding layer. A p-type GaN contact layer is grown so as not to be lattice-relaxed on the p-type cladding layer, to produce a semiconductor laser. Dislocation densities at junctions are larger than those at the other junctions.
摘要:
A group III nitride semiconductor device having a gallium nitride based semiconductor film with an excellent surface morphology is provided. A group III nitride optical semiconductor device 11a includes a group III nitride semiconductor supporting base 13, a GaN based semiconductor region 15, an active layer active layer 17, and a GaN semiconductor region 19. The primary surface 13a of the group III nitride semiconductor supporting base 13 is not any polar plane, and forms a finite angle with a reference plane Sc that is orthogonal to a reference axis Cx extending in the direction of a c-axis of the group III nitride semiconductor. The GaN based semiconductor region 15 is grown on the semipolar primary surface 13a. A GaN based semiconductor layer 21 of the GaN based semiconductor region 15 is, for example, an n-type GaN based semiconductor, and the n-type GaN based semiconductor is doped with silicon. A GaN based semiconductor layer 23 of an oxygen concentration of 5×1016 cm−3 or more provides an active layer 17 with an excellent crystal quality, and the active layer 17 is grown on the primary surface of the GaN based semiconductor layer 23.
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. 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 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:
In the nitride based semiconductor optical device LE1, the strained well layers 21 extend along a reference plane SR1 tilting at a tilt angle α from the plane that is orthogonal to a reference axis extending in the direction of the c-axis. The tilt angle α is in the range of greater than 59 degrees to less than 80 degrees or greater than 150 degrees to less than 180 degrees. A gallium nitride based semiconductor layer P is adjacent to a light-emitting layer SP− with a negative piezoelectric field and has a band gap larger than that of a barrier layer. The direction of the piezoelectric field in the well layer W3 is directed in a direction from the n-type layer to the p-type layer, and the piezoelectric field in the gallium nitride based semiconductor layer P is directed in a direction from the p-type layer to the n-type layer. Consequently, the valence band, not the conduction band, has a dip at the interface between the light-emitting layer SP− and the gallium nitride based semiconductor layer P.