Detecting pinholes in vertical cavity surface-emitting laser passivation
View Patent ↗A method for detecting a passivation pinhole includes forming an oxide vertical cavity surface-emitting laser (VCSEL) having an oxidation cavity, forming a passivation layer over a surface of the oxidation cavity, exposing the oxide VCSEL to an etchant vapor, and inspecting the oxide VCSEL for a defect caused by the etchant vapor.
1. A method for detecting a passivation pinhole, comprising:
forming an oxide vertical cavity surface-emitting laser (VCSEL) having an oxidation cavity;
forming a passivation layer over a surface of the oxidation cavity;
exposing the oxide VCSEL to an hotplate and pressurized by a supply of an inert gas.
2. The method of claim 1 , wherein said inspecting the oxide VCSEL comprises examining the oxide VCSEL under an infrared light.
3. The method of claim 2 , wherein said inspecting the oxide VCSEL further comprises examining the oxide VCSEL with an infrared filter.
4. The method of claim 1 , wherein the defect appears under infrared light as an oxidation front caused by the etchant.
5. The method of claim 1 , wherein the etchant is in a vapor form.
6. The method of claim 5 , wherein the oxide VCSEL is exposed to the etchant inside a furnace.
7. The method of claim 1 , wherein the etchant comprises a hydrochloric acid (HCl) vapor.
8. The method of claim 7 , further comprising heating a wet HCl to generate the (HCl) vapor.
9. The method of claim 8 , wherein the wet HCl is heated to 30° C.
10. The method of claim 9 , wherein the HCl vapor is pressurized by an inert gas supplied at one standard liter per minute.
11. The method of claim 10 , wherein the oxide VCSEL is exposed to the HCl vapor inside a furnace at 285° C.
12. The method of claim 11 , wherein the oxide VCSEL is exposed to the HCl vapor for two hours.