Abstract: A thermal contraction stress and a residual contraction stress caused by a difference between the linear expansion coefficients of an optical element unit and a carrier are reduced as much as possible. An optical module includes an optical element unit including optical elements requiring a stress control, and a carrier which supports the optical element unit. As the carrier is made of a material having the same property as that of the substrate material of the optical element, the thermal contraction stress is reduced.

Abstract: Distortion of the temperature control element and the package by thermal deformation or mechanical deformation is prevented from being transmitted to the optical element as stress, and at the same time, constant temperature control of the optical element is realized. An optical element unit including an optical element that requires temperature control and an optical component that does not require temperature control, and a temperature control element for performing temperature adjustment of the optical element are arranged. The temperature control element performs temperature adjustment control of the optical element through a region mounted with the optical component of the optical element unit.

Abstract: A thermal contraction stress and a residual contraction stress caused by a difference between the linear expansion coefficients of an optical element unit and a carrier are reduced as much as possible. An optical module includes an optical element unit including optical elements requiring a stress control, and a carrier which supports the optical element unit. As the carrier is made of a material having the same property as that of the substrate material of the optical element, the thermal contraction stress is reduced.

Abstract: Distortion of the temperature control element and the package by thermal deformation or mechanical deformation is prevented from being transmitted to the optical element as stress, and at the same time, constant temperature control of the optical element is realized. An optical element unit including an optical element that requires temperature control and an optical component that does not require temperature control, and a temperature control element for performing temperature adjustment of the optical element are arranged. The temperature control element performs temperature adjustment control of the optical element through a region mounted with the optical component of the optical element unit.

Abstract: The present invention provides a semiconductor device having a semiconductor multi-layer structure which includes at least an active layer having at least a quantum well, and the active layer further including at least a luminescent layer of InxAlyGa1-x-yN (0<x<1, 0?y?0.2), wherein a threshold mode gain of each of the at least quantum well is not more than 12 cm?1, and wherein a standard deviation of a microscopic fluctuation in a band gap energy of the at least luminescent layer is in the range of 75 meV to 200 meV.

Abstract: The present invention provides a semiconductor device having a semiconductor multi-layer structure which includes at least an active layer having at least a quantum well, and the active layer further including at least a luminescent layer of InxAlyGa1-x-yN (0<x<1, 0?y?0.2), wherein a threshold mode gain of each of the at least quantum well is not more than 12 cm?1, and wherein a standard deviation of a microscopic fluctuation in a band gap energy of the at least luminescent layer is in the range of 75 meV to 200 meV.

Abstract: The present invention provides a semiconductor device having a semiconductor multi-layer structure which includes at least an active layer having at least a quantum well, and the active layer further including at least a luminescent layer of InxAlyGa1?x?yN (0<x<1, 0?y?0.2), wherein a threshold mode gain of each of the at least quantum well is not more than 12 cm?1, and wherein a standard deviation of a microscopic fluctuation in a band gap energy of the at least luminescent layer is in the range of 75 meV to 200 meV.

Abstract: A nitride based semiconductor photo-luminescent device has an active layer having a quantum well structure. The active layer has both a high dislocation density region and a low dislocation density region that is lower in dislocation density than the high dislocation density region, wherein the low dislocation density region includes a current injection region into which a current is injected, and the active layer is less than 1×1018 cm?3 in impurity concentration.

Abstract: A nitride based semiconductor photo-luminescent device has an active layer having a quantum well structure. The active layer has both a high dislocation density region and a low dislocation density region that is lower in dislocation density than the high dislocation density region, wherein the low dislocation density region includes a current injection region into which a current is injected, and the active layer is less than 1×1018 cm?3 in impurity concentration.

Abstract: A light-emitting semiconductor device includes an active layer interposed between first-side and second-side cladding layer, and at least one of first-side and second-side optical guide layers. The following four equations are satisfied: 0.15≦h; |x−y|≦0.02; 0.02≦x≦0.06; and 0.34x−0.49≦d1+2h, where “h” is a total thickness of the first-side and second-side optical guide layers; “d1” is a thickness of the first-side cladding layer; “x” is a first Al-index of a first AlGaN bulk crystal which has a first refractive index equal to a first averaged refractive index of the first-side cladding layer; and “y” represents a second Al-index of a second AlGaN bulk crystal which has a second refractive index equal to a second averaged refractive index of the second-side cladding layer.

Abstract: A light-emitting semiconductor device includes an active layer interposed between first-side and second-side cladding layer, and at least one of first-side and second-side optical guide layers.

Abstract: For forming a contact electrode to an n-type contact layer of a gallium nitride-based compound semiconductor, the n-type contact layer of the gallium nitride-based compound semiconductor is exposed to an oxygen plasma to form an oxygen-doped surface layer in a surface of the n-type contact layer, and then, an electrode metal is formed on the oxygen-doped surface layer. With this arrangement, an n-type contact electrode having a low specific contact resistance is obtained with good reproducibility, with performing no annealing after formation of the electrode metal.

Abstract: A semiconductor device and method of forming a current block layer structure includes the steps of providing dielectric stripe masks defining at least a stripe-shaped opening on a surface of a compound semiconductor region having a hexagonal crystal structure, and selectively growing at least a current block layer of a compound semiconductor having the hexagonal crystal structure on the surface of the compound semiconductor region by use of the dielectric stripe masks.

Abstract: The present invention provides a semiconductor device having a semiconductor multi-layer structure which includes at least an active layer having at least a quantum well, and the active layer further including at least a luminescent layer of InxAlyGa1-x-yN (0<x<1, 0≦y≦0.2), wherein a threshold mode gain of each of the at least quantum well is not more than 12 cm−1, and wherein a standard deviation of a microscopic fluctuation in a band gap energy of the at least luminescent layer is in the range of 75 meV to 200 meV.

Abstract: For forming a contact electrode to an n-type contact layer of a gallium nitride-based compound semiconductor, the n-type contact layer of the gallium nitride-based compound semiconductor is exposed to an oxygen plasma to form an oxygen-doped surface layer in a surface of the n-type contact layer, and then, an electrode metal is formed on the oxygen-doped surface layer. With this arrangement, an n-type contact electrode having a low specific contact resistance is obtained with good reproducibility, with performing no annealing after formation of the electrode metal.

Abstract: For forming a contact electrode to an n-type layer of a gallium nitride-based compound semiconductor, the n-type contact layer of the gallium nitride-based compound semiconductor is exposed to an oxygen plasma to form an oxygen-doped surface layer in a surface of the n-type contact layer, and then, an electrode metal is formed on the oxygen-doped surface layer. With this arrangement, an n-type contact electrode having a low specific contact resistance is obtained with good reproducibility, with performing no annealing after formation of the electrode metal.

Abstract: For forming a contact electrode to an n-type contact layer of a gallium nitride-based compound semiconductor, the n-type contact layer of the gallium nitride-based compound semiconductor is exposed to an oxygen plasma to form an oxygen-doped surface layer in a surface of the n-type contact layer, and then, an electrode metal is formed on the oxygen-doped surface layer. With this arrangement, an n-type contact electrode having a low specific contact resistance is obtained with good reproducibility, with performing no annealing after formation of the electrode metal.

Abstract: The first present invention provides a nitride based semiconductor photo-luminescent device having an active layer having a quantum well structure, the active layer having both at least a high dislocation density region and at least a low dislocation density region lower in dislocation density than the high dislocation density region, wherein the low dislocation density region includes a current injection region into which a current is injected, and the active layer is less than 1×1018 m−3 in impurity concentration.

Abstract: A semiconductor device and method of forming a current block layer structure includes the steps of providing dielectric stripe masks defining at least a stripe-shaped opening on a surface of a compound semiconductor region having a hexagonal crystal structure, and selectively growing at least a current block layer of a compound semiconductor having the hexagonal crystal structure on the surface of the compound semiconductor region by use of the dielectric stripe masks.

Abstract: A method of crystal growth of a GaN layer with an extremely high surface planarity over a GaAs substrate is provided, wherein a GaAs substrate is heated to a temperature in the range of 600.degree. C. to 700.degree. C. without supplying any group-V element including arsenic to form a Ga-rich surface on the GaAs substrate, before a first source material including N and a second source material including Ga are supplied along with a carrier gas onto a surface of the GaAs substrate to form a GaN layer over the GaAs substrate.