Surface light emitting semiconductor laser element

Patent metadata

Field	Value
Publication number	US-2018341076-A1
Application number	US-201816012400-A
Country	US
Kind code	A1
Filing date	Jun 19, 2018
Priority date	May 19, 2003
Publication date	Nov 29, 2018
Grant date	—

Abstract

A surface light emitting semiconductor laser element, comprises a substrate, a lower reflector including a semiconductor multi-layer disposed on the substrate, an active layer disposed on the lower reflector, an upper reflector including a semiconductor multi-layer disposed on the active layer, a compound semiconductor layer having a first opening for exposing the upper reflector and extending over the upper reflector, and a metal film having a second opening for exposing the upper reflector disposed inside of the first opening and extending over the compound semiconductor layer, wherein the metal film and the compound semiconductor layer constitute a complex refractive index distribution structure where a complex refractive index is changed from the center of the second opening towards the outside. A method of emitting laser light in a single-peak transverse mode is also provided.

First claim

What is claimed is:

1 . A surface light emitting semiconductor laser element, comprising:
a substrate, a lower reflector, including a semiconductor multi-layer, disposed on the substrate, an active layer disposed on the lower reflector, an upper reflector, including a semiconductor multi-layer, disposed on the active layer, a compound semiconductor layer having a first opening for exposing the upper reflector and extending over the upper reflector, and a metal film having a second opening for exposing the upper reflector disposed inside of the first opening and extending over the compound semiconductor layer, wherein the metal film and the compound semiconductor layer constitute a complex refractive index distribution structure where a complex refractive index is changed from the center of the second opening towards the outside.

2 . A surface light emitting semiconductor laser element according to claim 1 , wherein in the complex refractive index distribution structure, the complex refractive index is changed isotropically from the center of the second opening towards the outside.

3 . A surface light emitting semiconductor laser element, comprising:
a substrate, a lower reflector, including a semiconductor multi-layer, disposed on the substrate, an active layer disposed on the lower reflector, an upper reflector, including a semiconductor multi-layer, disposed on the active layer, a compound semiconductor layer having a first opening for exposing the upper reflector and extending over the upper reflector, and a metal film including an annular film and an island-like film, the annular film having a second opening for exposing the upper reflector being disposed inside of the first opening, the annular film extending over the compound semiconductor layer, and the island-like film being disposed like islands on the upper reflector within the second opening, wherein the metal film and the compound semiconductor layer constitute a complex refractive index distribution structure where a complex refractive index is changed from the center of the second opening towards the outside.

4 . A surface light emitting semiconductor laser element according to claim 1 , further comprising an insulation film having a third opening disposed outside of the first opening for exposing the compound semiconductor layer, interposed between the compound semiconductor layer and the metal film, wherein the metal film, the compound semiconductor layer, and the insulation film constitute a complex refractive index distribution structure where a complex refractive index is changed from the center of the second opening towards the outside.

5 . A surface light emitting semiconductor laser element according to claim 3 , further comprising an insulation film having a third opening disposed outside of the first opening for exposing the compound semiconductor layer, interposed between the compound semiconductor layer and the metal film, wherein the metal film, the compound semiconductor layer, and the insulation film constitute a complex refractive index distribution structure where a complex refractive index is changed from the center of the second opening towards the outside.

6 . A surface light emitting semiconductor laser element according to claim 1 , wherein the compound semiconductor layer having the first opening comprises a plurality of layers having different impurity concentrations,
each of the first openings disposed on respective compound semiconductor layers has a diameter that becomes smaller step-wise from an upper layer to a lower layer of the plurality of compound semiconductor layers, and each of the impurity concentrations of respective compound semiconductor layers gradually decreases step-wise from the upper layer to the lower layer of the plurality of compound semiconductor layers.

7 . A surface light emitting semiconductor laser element according to claim 3 , wherein the compound semiconductor layer having the first opening comprises a plurality of layers having different impurity concentrations,
each of the first openings disposed on respective compound semiconductor layers has a diameter that becomes smaller step-wise from an upper layer to a lower layer of the plurality of compound semiconductor layers, and each of the impurity concentrations of respective compound semiconductor layers gradually decreases step-wise from the upper layer to the lower layer of the plurality compound semiconductor layers.

8 . A surface light emitting semiconductor laser element according to claim 1 , wherein the metal film constitutes an electrode, and the compound semiconductor layer constitutes a contact layer in ohmic contact with the metal film.

9 . A surface light emitting semiconductor laser element according to claim 1 , further comprising a current confinement layer adjacent to the upper reflector or the active layer on the lower reflector, and which is formed as a mesa post.

10 . A surface light emitting semiconductor laser element according to claim 1 , wherein a current confinement layer has a non-oxidized current injection area at the center, and wherein the non-oxidized current injection area is disposed under the first opening, has an impurity concentration of 5×10 18 cm −3 , and has uniform current injection density.

11 . A method of producing a surface light emitting semiconductor laser element, comprising the steps of:
sequentially laminating a lower reflector including a semiconductor multi-layer, an active layer, an upper reflector including a semiconductor multi-layer having a layer with a high Al content, and a contact layer on a substrate, etching the upper reflector having the layer with the high Al content to form a mesa post, forming an insulation film on the contact layer of the mesa post and a side of the mesa post, forming an opening on the insulation film over the contact layer to expose the contact layer, forming an opening on the contact layer smaller than the opening of the insulation film to expose the upper reflector, forming a metal film for constituting an electrode on the upper reflector and the contact layer, and forming an opening on the metal film smaller than the opening on the contact film to expose the upper reflector.

12 . A method of producing a surface light emitting semiconductor laser element according to claim 11 , further comprising the steps of:
oxidizing the layer with the high Al content of the mesa post under steam to leave a center area of the layer with high Al content as a first current injection area including a layer with an non-oxidized high Al content, after the step of forming the mesa post, and forming a current confinement area comprising an oxidized-Al layer surrounding the current injection area.

13 . A method of producing a surface light emitting semiconductor laser element according to claim 11 , wherein in the step of forming the contact layer on the upper reflection layer, a plurality of contact layers are formed so that each of the impurity concentrations decreases step-wise or gradually from the upper layer to the lower layer, and wherein in the step of forming the opening on the contact layer smaller than the opening of the insulation film to expose the upper reflector, the opening is formed on each contact layer so that each opening diameter decreases step-wise or gradually from the upper layer to the lower layer by utilizing a difference in etching rates by the fact that each of the impurity concentrations decreases step-wise or gradually from the upper layer to the lower layer.

14 . A method of producing a surface light emitting semiconduct

Assignees

• Sony Corp

Inventors

• Watanabe Yoshiaki
• Narui Hironobu
• Kuromizu Yuichi
• Yamauchi Yoshinori
• Tanaka Yoshiyuki

Classifications

• H01S5/0425

  Electrodes, e.g. characterised by the structure · CPC title

• H01S5/04254 Primary

  characterised by the shape · CPC title

• H01S2301/176

  Specific passivation layers on surfaces other than the emission facet · CPC title

• H01S5/18311

  using selective oxidation · CPC title

• H01S5/18394

  Apertures, e.g. defined by the shape of the upper electrode · CPC title