CN-115191033-B - Light emitting diode device with common electrode

Abstract

A Light Emitting Diode (LED) device is described that includes a plurality of mesas defining pixels, each of the plurality of mesas including a semiconductor layer, an n-contact material in a space between each of the plurality of mesas, and a dielectric material insulating sidewalls of the p-type layer and the active region from metal. The plurality of mesas define a matrix of pixels surrounded by a common electrode comprising a plurality of semiconductor stacks surrounded by a conductive metal. Each semiconductor stack is passive and, in one or more embodiments, includes at least one layer of GaN.

Inventors

• E.W.Yang
• R. SHARMA
• D. SCOTT

Assignees

• 亮锐有限责任公司

Dates

Publication Date

20260505

Application Date

20210308

Priority Date

20210305

Claims (18)

1. 1. A Light Emitting Diode (LED) device, comprising: A plurality of mesas defining pixels, each mesa comprising a semiconductor layer comprising an n-type layer, an active region and a p-type layer, each mesa having a height less than or equal to its width; an n-contact material between each mesa that provides optical isolation between each mesa and electrically contacts the n-type layer of each mesa along sidewalls of the n-type layer; A first dielectric material insulating sidewalls of the p-type layer and the active region from the n-contact material; A current spreading layer on the p-type layer, the current spreading layer having a first portion and a second portion; A hard mask layer over a second portion of the current spreading layer; a plug of p-metal material over a first portion of the current spreading layer; a passivation layer on the hard mask layer; an under bump metallization layer on the passivation layer; A reflective liner deposited on the first dielectric material, on the sidewalls and bottom of the trench between the mesas, along the hard mask layer, and on the p-type layer, and A plurality of mesas defining a pixel matrix, the pixel matrix surrounded by a common electrode comprising a plurality of semiconductor stacks surrounded by a conductive metal.
2. 2. The LED device of claim 1, wherein each semiconductor stack is a passive semiconductor stack comprising at least one layer of GaN.
3. 3. The LED device of claim 1, wherein the p-metal material plug has a width in the range from 2 μιη to 30 μιη.
4. 4. The LED device of claim 1, wherein the pixel pitch of the plurality of mesas is in a range from 5 μιη to 100 μιη.
5. 5. The LED device of claim 1, wherein the semiconductor layer has a thickness in a range from 2 μιη to 10 μιη.
6. 6. The LED device of claim 1, wherein the first dielectric material is in the form of an external spacer comprising a material selected from the group consisting of SiO 2 、AlO x and SiN, having a thickness in the range from 200: 200 nm to 1 μιη.
7. 7. The LED device of claim 1, comprising a trench having a depth from a top surface of the mesa in a range from 0.5 μιη to 2 μιη, the trench comprising an n-contact material.
8. 8. The LED device of claim 1 wherein each mesa comprises a sidewall of the semiconductor layer, each sidewall having a first segment and a second segment, wherein the first segment of the sidewall defines an angle in the range of from 60 degrees to 90 degrees with a horizontal plane parallel to the n-type layer and the p-type layer, and the second segment of the sidewall forms an angle in the range of from 75 degrees to less than 90 degrees with a top surface of a substrate on which the mesa is formed.
9. 9. The LED device of claim 1, wherein the plurality of mesas comprises an array of mesas.
10. 10. 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; Etching a portion of the semiconductor layer to form a trench defining a plurality of pixels and a plurality of mesas, each of the plurality of mesas including the semiconductor layer and each mesa having a height less than or equal to its width; Depositing a first dielectric material in the trench; Depositing a reflective liner in the trench and over the semiconductor layer; depositing an n-contact material on the first dielectric material, the n-contact material providing optical isolation between each mesa and electrically contacting the n-type layer of each mesa along sidewalls of the n-type layer, wherein the dielectric material insulates the p-type layer and sidewalls of the active region from the n-contact material, and A common electrode is formed comprising a plurality of semiconductor stacks surrounded by a conductive metal, the common electrode surrounding the plurality of pixels.
11. 11. The method of claim 10, wherein each semiconductor stack is a passive semiconductor stack comprising at least one layer of GaN.
12. 12. The method of claim 10, further comprising forming a mesa array.
13. 13. The method of claim 10, wherein the n-contact material comprises a reflective metal.
14. 14. The method of claim 10, wherein a pixel pitch of the plurality of mesas is in a range from 5 μιη to 100 μιη.
15. 15. The method of claim 10, wherein the thickness of the semiconductor layer is in a range from 2 μιη to 10 μιη.
16. 16. A Light Emitting Diode (LED) device, comprising: A plurality of mesas defining pixels, each mesa comprising a semiconductor layer comprising an n-type layer, an active region and a p-type layer, each mesa having a height less than or equal to its width; an n-contact material in the space between each mesa that provides optical isolation between each mesa and electrically contacts the n-type layer of each mesa along sidewalls of the n-type layer; A first dielectric material insulating sidewalls of the p-type layer and the active region from the n-contact material; A current spreading layer on the p-type layer, the current spreading layer having a first portion and a second portion; A hard mask layer over a second portion of the current spreading layer; a plug of p-metal material over a first portion of the current spreading layer; a passivation layer on the hard mask layer; an under bump metallization layer on the passivation layer; A reflective liner deposited on the first dielectric material, on the sidewalls and bottom of the trench between the mesas, along the hard mask layer, and on the p-type layer, and A plurality of mesas defining a pixel matrix surrounded by a common electrode comprising a plurality of passive semiconductor stacks, each semiconductor stack comprising at least one layer of GaN, the plurality of passive semiconductor stacks surrounded by a conductive metal.
17. 17. The LED device of claim 16, wherein the plurality of mesas comprises an array of mesas.
18. 18. The LED device of claim 16, wherein the pixel pitch of the plurality of mesas is in a range from 5 μιη to 100 μιη.

Description

Light emitting diode device with common electrode Technical Field Embodiments of the present disclosure generally relate to Light Emitting Diode (LED) devices and methods of manufacturing the same. More particularly, embodiments relate to a light emitting diode device including a common electrode. Background A Light Emitting Diode (LED) is a semiconductor light source that emits visible light when current flows through it. The light emitting diode combines a p-type semiconductor and an n-type semiconductor. LEDs typically use group III-V compound semiconductors. The III-V compound semiconductor provides stable operation at higher temperatures than devices using other semiconductors. Group III-V compounds are typically formed on substrates formed of sapphire alumina (Al 2O3) or silicon carbide (SiC). Various emerging display applications, including wearable devices, head mounted displays, and large area displays, require miniaturized chips consisting of high density microLED (μled or uLED) arrays with lateral dimensions as low as less than 100 μm by 100 μm. microLED (uLED), typically about 50 μm or less in diameter or width, are used to fabricate color displays by closely arranging microLED containing red, blue and green wavelengths. Generally, two approaches have been used to assemble displays made up of a single microLED die. The first is a pick and place method that includes picking up each individual blue, green, and red wavelength microLED, aligning each individual blue, green, and red wavelength microLED, and then attaching each individual blue, green, and red wavelength microLED to the backplate, which is then electrically connected to the driver integrated circuit. Because of the small size of each microLED, this assembly sequence is slow and prone to manufacturing errors. Furthermore, as die sizes decrease to meet ever increasing resolution requirements of displays, an increasing number of dies must be transferred in each pick and place operation to fill the desired size display. The second approach is to bond a group of LEDs (e.g., a monolithic die or array or matrix) to the back plate, which eliminates the handling of individual LEDs associated with pick-and-place. Accordingly, there is a need to develop methods for efficiently preparing LED groups that can then be used for bonding to LED backplanes. Disclosure of Invention Embodiments of the present disclosure are directed to a Light Emitting Diode (LED) device including a plurality of mesas defining pixels, each of the plurality of mesas including a semiconductor layer including an n-type layer, an active region, and a p-type layer, each mesa having a height less than or equal to a width thereof, an n-contact material between each of the plurality of mesas providing optical isolation between each mesa and electrically contacting the n-type layer of each mesa along sidewalls of the n-type layer, a first dielectric material insulating the sidewalls of the p-type layer and the active region from the n-contact material, and a plurality of mesas defining a pixel matrix including a plurality of semiconductor stacks surrounded by a conductive metal. Additional embodiments are directed to a Light Emitting Diode (LED) device comprising a plurality of mesas defining a pixel, each of the plurality of mesas comprising a semiconductor layer comprising an n-type layer, an active region, and a p-type layer, each mesa having a height less than or equal to its width, an n-contact material in a space between each of the plurality of mesas that provides optical isolation between each mesa and electrically contacts the n-type layer of each mesa along sidewalls of the n-type layer, a first dielectric material insulating the sidewalls of the p-type layer and the active region from the n-contact material, a current diffusion layer on the p-type layer having a first portion and a second portion, a hard mask layer over the second portion of the current diffusion layer, a plug of p-metal material (METAL MATERIAL plug) over the first portion of the current diffusion layer, a passivation layer over the hard mask layer, an under-bump metallization layer over the passivation layer, and a plurality of mesas defining a matrix of pixels, the pixel being surrounded by a common semiconductor stack comprising at least one passive metal stack surrounded by the at least one passive metal stack. Further embodiments are directed to a method of fabricating 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, etching a portion of the semiconductor layers to form a trench defining a plurality of pixels and a plurality of mesas, each of the plurality of mesas including the semiconductor layer and each mesa having a height less than or equal to its width, depositing a first dielectric material in the trench, depositing an n-contact material on the first dielectric materi