Light emitting diode devices with defined hard mask opening
Described are light emitting diode (LED) devices comprising a plurality of mesas defining pixels, each of the mesas comprising semiconductor layers, an N-contact material in a space between each of the plurality of mesas, a dielectric material which insulates sidewalls of the P-type layer and the active region from the metal. A hard mask layer is above the semiconductor layers, the hard mask layer having a plurality of openings therein, each partially filled with a liner layer and partially filled with a P-metal material plug, the P-metal material plug having a width; and a passivation film is on the hard mask layer, the passivation film having a plurality of passivation film openings therein defining a width, the width of each passivation film opening being less than the width of a combination of the P-metal material plug and the liner layer.
1. A light emitting diode (LED) device comprising:
a plurality of mesas defining pixels, each of the mesas comprising semiconductor layers, the semiconductor layers including an N-type layer, an active region, and a P-type layer, each of the mesas having a height less than or equal to their width;
an N-contact material in a space between each of the mesas, the metal providing optical isolation between each of the mesas, and electrically contacting the N-type layer of each of the mesas along sidewalls of the N-type layers;
a dielectric material which insulates sidewalls of the P-type layer and the active region from the N-contact material;
a hard mask layer above the semiconductor layers, the hard mask layer having a plurality of openings therein, each partially filled with a liner layer and partially filled with a P-metal material plug, the P-metal material plug having a width; and
a passivation film on the hard mask layer, the passivation film having a plurality of passivation film openings therein defining a width, the width of each passivation film opening being less than the width of a combination of the P-metal material plug and the liner layer.
2. The LED device of claim 1 , wherein the passivation film covers a surface of the liner layer and a portion of the P-metal material plug.
3. The LED device of claim 1 , wherein the passivation film opening is centered to the P-metal material plug.
4. The LED device of claim 1 , wherein the P-metal material plug comprises copper.
5. The LED device of claim 1 , wherein the plurality of mesas comprises an array of mesas.
6. The LED device of claim 1 , wherein the width of the combination of the P-metal material plug and the liner layer is in a range of from 2 μm to 30 μm.
7. The LED device of claim 6 , wherein the width of the combination of the P-metal material plug and the liner layer is in a range of from 10 μm to 20 μm.
8. The LED device of claim 1 , wherein a pixel pitch of the plurality of mesas is in a range of from 5 μm to 100 μm.
9. The LED device of claim 8 , wherein the pixel pitch in range of from 30 μm to 50 μm.
10. The LED device of claim 1 , wherein the semiconductor layers have a thickness in a range of from 2 μm to 10 μm.
11. The LED device of claim 1 , wherein the dielectric material is in a form of outer spacers comprising a material selected from the group consisting of SiO 2 , AlO x , and SiN, having a thickness in a range of from 200 nm to 1 μm.
12. The LED device of claim 1 , wherein the space between each of the mesas comprises a trench having a depth from a top surface of each of the mesas in a range of from 0.5 μm to 2 μm.
13. The LED device of claim 1 , wherein each of the mesas includes sidewalls of the semiconductor layers, each having a first segment and a second segment, wherein the first segments of the sidewalls define an angle in a range of from 60 degrees to 90 degrees from a horizontal plane that is parallel with the N-type layer and the P-type layer; and the second segments of the sidewalls form an angle with a top surface of a substrate upon which the mesas are formed in a range of from 75 to less than 90 degrees.
14. A method of manufacturing a light emitting diode (LED) device comprising:
depositing a plurality of semiconductor layers including an N-type layer, an active region, and a P-type layer on a substrate;
depositing a hard mask layer over the P-type layer;
etching a portion of the semiconductor layers and the hard mask layer to form trenches and plurality of mesas defining pixels, each of the mesas comprising the semiconductor layers and each of the mesas having a height less than or equal to their width;
depositing a dielectric material in the trenches;
forming an opening in the hard mask layer, and etching the semiconductor layers to expose a surface of the substrate and a sidewall of the N-type layer;
depositing a liner layer on the substrate, including on surfaces of the opening in the hard mask layer, the dielectric material, the N-type layer, and substrate;
depositing an electrode metal on the liner layer;
planarizing the substrate to form an N-contact material electrically contacting the N-type layer of each of the mesas along sidewalls of the N-type layers, and a P-metal material plug on the liner layer in the opening of the hard mask layer, a combination of the P-metal material plug and the liner layer in the opening of the hard mask layer having a width; and
forming a passivation layer on the substrate and forming openings in the passivation layer defining a width, the width of each opening in the passivation layer being less than the width of the combination of the P-metal material plug and the liner layer.
15. The method of claim 14 , wherein the P-metal material plug comprises copper.
16. The method of claim 14 , wherein the width of the combination of the P-metal material plug and the liner layer is in a range of from 2 μm to 30 μm.
17. The method of claim 14 , wherein a pixel pitch of the plurality of mesas is in a range of from 5 μm to 100 μm.
18. The method of claim 14 , wherein the semiconductor layers have a thickness in a range of from 2 μm to 10 μm.