Semiconductor laser element, semiconductor etchant, and method of fabricating the semiconductor laser element
AssigneeFurukawa Electric Co., Ltd.
InventorsTakeshi Shiojima, Keiichi Yabusaki, Michio Ohkubo
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Abstract
The semiconductor laser element comprises, from bottom to top, the p-AlxGa1-xAs upper clad layer, p-AlyGa1-yAs resistance control layer, and p-GaAs cap layer (where x>y>0.2). A portion of only the resistance control layer and cap layer is selectively etched. The etchant used for this etching is a mixture of organic acid and hydrogen peroxide based mixture, has such a composition such that the ratio of dissolution rate of the upper clad layer to the cap layer is between 10 and 20, and pH is between 7.4 and 7.6.
Claims34
A semiconductor laser element having a laser-emission side end facet, comprising:
- a semiconductor substrate;
- a clad layer stacked directly above said semiconductor substrate or above some other layer stacked above said semiconductor substrate;
- a resistance control layer stacked above said clad layer and which controls a junction resistance between said clad layer and a cap layer stacked above said resistance control layer;
- said cap layer has a shape such that it narrows an electric current flowing in active layers;
- wherein
- a portion of said cap layer and said resistance control layer in the vicinity of said laser-emission side end facet is removed by selective etching, and
- an insulating layer having a thickness which is the same as the total thickness of said cap layer and said resistance control layer is formed in the portion that became hollow due to etching;
- and
- a top electrode layer stacked above said cap layer and said insulating layer.
A semiconductor laser element having a laser-emission side end facet, comprising:
- a semiconductor substrate;
- a clad layer stacked directly above said semiconductor substrate or above some other layer stacked above said semiconductor substrate;
- a resistance control layer stacked above said clad layer and which controls a junction resistance between said clad layer and a cap layer stacked above said resistance control layer;
- said cap layer has a shape such that it narrows an electric current flowing in active layers;
- wherein
- a portion of said cap layer and said resistance control layer in the vicinity of said laser-emission side end facet is removed by selective etching, and
- an insulating film which covers the surface of said clad layer exposed due to the etching, side faces of said resistance control layer and said cap layer, and a portion of top surface of said cap layer;
- and
- a top electrode layer stacked above said cap layer and said insulating film.
An etchant for selectively etching only a first and second layers of a multilayered semiconductor laser element comprising at least a third layer and said second and first layers stacked successively on a semiconductor substrate, wherein said second layer controls resistance of said multilayered semiconductor laser element, wherein
- said etchant has such a composition that the ratio of dissolution rate of said first semiconductor layer to said third semiconductor layer is between 10 and 20.
A method of fabricating a semiconductor laser element, said semiconductor laser element having a laser-emission side end facet, the method comprising the steps of:
- stacking a semiconductor substrate;
- stacking a clad layer directly above said semiconductor substrate or above some other layer stacked above said semiconductor substrate;
- stacking a resistance control layer above said clad layer which controls a junction resistance between said clad layer and a cap layer stacked above said resistance control layer, said cap layer has a shape such that it narrows an electric current flowing in active layers;
- selective etching a portion of said cap layer and said resistance control layer in the vicinity of said laser-emission side end facet;
- stacking an insulating layer having a thickness which is the same as the total thickness of said cap layer and said resistance control layer in the portion that became hollow due to etching;
- and
- stacking a top electrode layer above said cap layer and said insulating layer.
A method of fabricating a semiconductor laser element, said semiconductor laser element having a laser-emission side end facet, the method comprising the steps of:
- stacking a semiconductor substrate;
- stacking a clad layer directly above said semiconductor substrate or above some other layer stacked above said semiconductor substrate;
- stacking a resistance control layer above said clad layer which controls a junction resistance between said clad layer and a cap layer stacked above said resistance control layer, said cap layer has a shape such that it narrows an electric current flowing in active layers;
- selective etching a portion of said cap layer and said resistance control layer in the vicinity of said laser-emission side end facet;
- stacking an insulating film which covers the surface of said clad layer exposed due to the etching, side faces of said resistance control layer and said cap layer, and a portion of top surface of said cap layer;
- and
- stacking a top electrode layer above said cap layer and said insulating film.
Dependencies are inferred from the claim text.