Semiconductor laser device and method for manufacturing the same
View Patent ↗The present invention provides a semiconductor laser device capable of improving reproducibility and electrical properties of the device, and a manufacturing method thereof. The semiconductor laser device according to the invention includes a first p type AlGaInP-based clad layer formed on an active layer, and a second p-type AlGaInP-based clad layer formed on the first p-type AlGaInP-based clad layer and having a ridge structure. The first p-type AlGaInP-based clad layer is Zn-doped with a concentration that restrains Zn diffusion into the active layer, and the second p-type AlGaInP-based clad layer is Mg-doped with a concentration higher than that of the first AlGaInP-based clad layer.
1. A semiconductor laser device comprising:
an n type AlGaInP-based clad layer formed on a substrate;
an active layer formed on the n-type AlGaInP-based clad layer;
a first p-type AlGaInP-based clad layer formed on the active layer; and
a second p-type AlGaInP-based clad layer having a ridge structure formed on the first p-type AlGaInP-based clad layer,
wherein the first p-type AlGaInP-based clad layer is Zn-doped with a concentration that restrains Zn diffusion into the active layer, and the second p-type AlGaInP-based clad layer is Mg-doped with a concentration higher than that of the first p-type AlGaInP-based clad layer.
2. The semiconductor laser device according to claim 1 , wherein the first p-type AlGaInP-based clad layer is Zn-doped with a concentration of 8×10 17 cm −3 or less.
3. The semiconductor laser device according to claim 1 , wherein the first p-type AlGaInP-based clad layer is Zn-doped with a concentration of 1×10 17 to 8×10 17 cm −3 .
4. The semiconductor laser device according to claim 1 , wherein the first p-type AlGaInP-based clad layer is Zn-doped with a concentration of 5×10 17 to 8×10 17 cm −3 .
5. The semiconductor laser device according to claim 1 , wherein the second p-type AlGaInP-based clad layer is Mg-doped with a concentration of at least 1×10 18 cm −3 .
6. The semiconductor laser device according to claim 1 , wherein the second p-type AlGaInP-based clad layer is Mg-doped with a concentration of 1×10 18 to 5×10 18 cm −3 .
7. The semiconductor laser device according to claim 1 , wherein the second p-type AlGaInP-based clad layer is Mg-doped with a concentration of 3×10 18 to 5×10 18 cm −3 .
8. The semiconductor laser device according to claim 1 , further comprising an etch stop layer formed between the first p-type AlGaInP-based clad layer and the second p-type AlGaInP-based p-type clad layer.
9. A method for manufacturing a semiconductor laser device comprising steps of:
sequentially forming an n-type AlGaInP-based clad layer and an active layer on a substrate;
forming a first p-type AlGaInP-based clad layer Zn-doped with a concentration that restrains Zn diffusion into the active layer;
selectively etching the second p-type AlGaInP-based clad layer to form a ridge structure;
and forming a second p-type AIGaInP-based clad layer Mg-doped with a concentration higher than that of the first p-type AlGaInP-based clad layer.
10. The method according to claim 9 , wherein the first p-type AlGaInP-based clad layer is Zn-doped with a concentration of 8×10 17 cm −3 or less.
11. The method according to claim 9 , wherein the first p-type AlGaInP-based clad layer is Zn-doped with a concentration of 1×10 17 to 8×10 17 cm −3 .
12. The method according to claim 9 , wherein the first p-type AlGaInP-based clad layer is Zn-doped with a concentration of 5×10 17 to 8×10 17 cm −3 .
13. The method according to claim 9 , wherein the second p-type AlGaInP-based clad layer is Mg-doped with a concentration of at least 1×10 18 cm −3 .
14. The method according to claim 9 , wherein the second p-type AlGaInP-based clad layer is Mg-doped with a concentration of 1×10 18 to 5×10 18 cm −3 .
15. The method according to claim 9 , wherein the second p-type AlGaInP-based clad layer is Mg-doped with a concentration of 3×10 18 to 5×10 18 cm −3 .
16. The method according to claim 9 , further comprising forming an etch-stop layer between the first p-type AlGaInP-based clad layer forming step and the second p-type AlGaInP-based clad layer forming step.