Semiconductor light-emitting element and manufacturing method thereof

A semiconductor light-emitting element, comprising:

• a substrate;
• and
• a nitride semiconductor multilayer film provided on an upper surface of the substrate and including an active layer that produces light during operation, wherein
• a recess a stepped portion, or a protruding portion is formed in an active layer or a layer of the nitride semiconductor multilayer film which contacts a lower surface of the active layer,
• a ridge stripe, which has a front end facet and a rear end facet facing the front end facet and serves as an optical waveguide, is formed in an upper part of the nitride semiconductor multilayer film,
• a distance from a lateral center of the ridge stripe to a lateral center of the recess, the stepped portion, or the protruding portion changes continuously or in stages from the front end facet toward the rear end facet,
• bandgap energy of the active layer changes continuously or in stages from the front end facet toward the rear end facet, and
• multiple ones of the recess, the stepped portion, or the protruding portion are provided discontinuously along the ridge stripe.

A semiconductor light-emitting element, comprising:

• a substrate;
• and
• a nitride semiconductor multilayer film provided on an upper surface of the substrate and including an active layer, wherein
• a recess, a stepped portion, or a protruding portion is formed in the active layer or a layer of the nitride semiconductor multilayer film which contacts a lower surface of the active layer,
• a ridge stripe, which has a front end facet and a rear end facet facing the front end facet and serves as an optical waveguide, is formed in an upper part of the nitride semiconductor multilayer film, and
• a depth of the recess, a depth of the stepped portion, or a height of the protruding portion changes continuously or in stages from the front end facet toward the rear end facet.

A method for manufacturing a semiconductor light-emitting element, comprising the steps of:

• (a) providing a recess, a stepped portion, or a protruding portion in a substrate or a semiconductor layer on the substrate, and then forming on an upper surface of the substrate or an upper surface of the semiconductor layer a nitride semiconductor multilayer film including an active layer that produces light during operation;
• and
• (b) forming in an upper part of the nitride semiconductor multilayer film a ridge stripe that has a front end facet and a rear end facet facing the front end facet and serves as an optical waveguide, wherein
• in the step (b), a depth of the recess, a depth of the stepped portion, or a height of the protruding portion changes continuously or in stages from the front end facet toward the rear end facet.

A method for manufacturing a semiconductor light-emitting element, comprising the steps of:

• (a) providing a recess, a stepped portion, or a protruding portion in a substrate or a semiconductor layer on the substrate, and then forming on an upper surface of the substrate or an upper surface of the semiconductor layer a nitride semiconductor multilayer film including an active layer that produces light during operation;
• and
• (b) forming in an upper part of the nitride semiconductor multilayer film a ridge stripe that has a front end facet and a rear end facet facing the front end facet and serves as an optical waveguide, wherein
• multiple ones of the recess, the stepped portion, or the protruding portion are provided discontinuously, and
• in the step (b), the ridge stripe is formed so that a distance from a lateral center of the ridge stripe to a lateral center of the recess, the stepped portion, or the protruding portion changes from the front end facet toward the rear end facet whereby bandgap energy of the active layer is changed continuously or in stages from the front end facet toward the rear end facet, and
• the ridge stripe is formed along the recesses, the stepped portions, or the protruding portions.