Nichia Corporation

Seiichi Hayashi

Hirofumi Nishiyama

Toshinori Wada

A light emitting element comprises a first n-side semiconductor layer, a first active layer having a first well layer containing indium, a first p-side semiconductor layer, a second n-side semiconductor layer in contact with the first p-side semiconductor layer, a second active layer having a second well layer containing indium, and a second p-side semiconductor, each formed of a nitride semiconductor. The second active layer has a first intermediate layer positioned closer to the first active layer than is the second well layer and containing indium. An indium composition ratio of the first well layer is less than an indium composition ratio of the second well layer. An indium composition ratio of the first intermediate layer is less than an indium composition ratio of the first well layer. A thickness of the first intermediate layer is less than a thickness of the second well layer.

Light emitting element

A method for manufacturing a light-emitting element, includes: introducing a gas comprising gallium, an ammonia gas, and a gas comprising a p-type impurity to a reactor and forming a first p-type nitride semiconductor layer on a first light-emitting layer in a state in which the reactor has been heated to a first temperature; introducing an ammonia gas at a first flow rate and a nitrogen gas to the reactor in a state in which the reactor is held at the first temperature; and subsequently introducing a gas comprising gallium, an ammonia gas at a second flow rate, and a gas comprising an n-type impurity to the reactor, and forming a second n-type nitride semiconductor layer on the first p-type nitride semiconductor layer. The first flow rate is less than the second flow rate.

Method for manufacturing light-emitting element

A method includes forming a first n-type nitride semiconductor layer; forming a first light-emitting layer on the first n-type nitride semiconductor layer; forming a first nitride semiconductor layer on the first light-emitting layer by introducing a gas comprising gallium and having a first flow rate; forming a first p-type nitride semiconductor layer on the first nitride semiconductor layer; forming an n-type intermediate layer on the first p-type nitride semiconductor layer; forming a second n-type nitride semiconductor layer on the n-type intermediate layer; forming a second light-emitting layer on the second n-type nitride semiconductor layer; forming a second nitride semiconductor layer on the second light-emitting layer by introducing a gas comprising gallium and having a second flow rate; and forming a second p-type nitride semiconductor layer on the second nitride semiconductor layer. The first flow rate is less than the second flow rate.

A method includes: introducing a gas including gallium, an ammonia gas, and a gas including a p-type impurity to a reactor and forming a first p-type nitride semiconductor layer on a first light-emitting layer in a state in which the reactor has been heated to a first temperature; lowering a temperature of the reactor from the first temperature to a second temperature; introducing an ammonia gas with a first flow rate to the reactor and increasing the temperature of the reactor from the second temperature to a third temperature; and introducing a gas including gallium, an ammonia gas with a second flow rate, and a gas including an n-type impurity to the reactor, and forming a second n-type nitride semiconductor layer on the first p-type nitride semiconductor layer in a state in which the reactor has been heated to the third temperature.

A light-emitting element includes: a first n-type nitride semiconductor layer; a first light-emitting layer located on the first n-type nitride semiconductor layer; a p-type GaN layer located on the first light-emitting layer; an n-type GaN layer located on the p-type GaN layer and doped with an n-type impurity at an impurity concentration higher than that of the first n-type nitride semiconductor layer; a non-doped GaN layer located between the p-type GaN layer and the n-type GaN layer, a thickness of the non-doped GaN layer being not more than a width of a depletion layer formed by the n-type and p-type GaN layers; a second n-type nitride semiconductor layer located on the n-type GaN layer and doped with an n-type impurity; a second light-emitting layer located on the second n-type nitride semiconductor layer; and a p-type nitride semiconductor layer located on the second light-emitting layer and doped with a p-type impurity.

Light-emitting element and method for manufacturing light-emitting element

A method for manufacturing a light-emitting element comprises: forming a mask comprising a first film and a second film such that the mask covers a first active layer and a second nitride semiconductor layer, which comprises: forming the first film covering at least an upper surface of the second nitride semiconductor layer, and forming the second film covering the first film; while the first active layer and the second nitride semiconductor layer are covered with the mask, forming a third nitride semiconductor layer at an exposed portion of a first nitride semiconductor layer, wherein a temperature at which the third nitride semiconductor layer is formed is less than a melting point of the second film; and after the forming of the third nitride semiconductor layer, removing the mask, during which lift-off of the mask is performed by removing the first film, which also removes the second film.

A semiconductor light emitting device is provided which has improved light emission efficiency. The semiconductor light emitting device includes an active layer having a quantum well structure. The quantum well structure includes well and barrier layers that are alternately and repeatedly deposited on one another. The well layer is formed of a gallium nitride group semiconductor that contains In. The well layer has a profile of composition ratio of In that includes a first portion, and a second portion that is in contact with the first portion. The concentration of In in the first portion is substantially fixed or reduced along the thickness direction of the well layer from the negative side to the positive side of the piezoelectric field that is produced in the well layer. The concentration of In in the second portion is sharply reduced with respect to the first portion.

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Anan, Japan

Seiichi Hayashi