News Column

Researchers Submit Patent Application, "Nano-Structure Semiconductor Light Emitting Device", for Approval

August 20, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Cha, Nam Goo (Ansan-si, KR); Kuh, Bong Jin (Suwon-si, KR); Choi, Han Mei (Seoul, KR), filed on January 27, 2014, was made available online on August 7, 2014.

The patent's assignee is Samsung Electronics Co., Ltd.

News editors obtained the following quote from the background information supplied by the inventors: "A light emitting diode (LED) is a semiconductor light emitting device in which materials included therein emit light. In an LED, energy generated according to electron-hole recombination is converted into light to be emitted therefrom. LEDs are commonly used as a light source in lighting devices and display devices, and as such, the development thereof has accelerated.

"Recently, in order to increase luminance efficiency by enhancing crystallinity and increasing a light emitting area, semiconductor light emitting devices using nano-structures and manufacturing techniques thereof have been developed. Semiconductor light emitting devices using nano-structures generate a relatively small amount of heat, and since an increased surface area of nano-structures is used, a light emitting area is increased to enhance luminous efficiency.

"Also, an active layer can be obtained from a non-polar plane or an anti-polar plane, a degradation of efficiency due to polarization can be prevented and droop characteristics can be improved.

"In case of a nano-structure semiconductor light emitting device, a light emitting structure is formed as a fine structure on the nano-scale, layers are formed to be very thin and delamination, or the like, may occur in an interface between a layer and a mask as an insulating layer. Thus, a leakage current may be generated when a device is driven."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "An aspect of the present disclosure provides a nano-structure semiconductor light emitting device having a novel structure capable of reducing a leakage current.

"According to an aspect of the present disclosure, there is provided a nano-structure semiconductor light emitting device including a base layer formed of a first conductivity type semiconductor and a first insulating layer disposed on the base layer and having a plurality of first openings exposing partial regions of the base layer. A plurality of nanocores is disposed in the exposed regions of the base layer and formed of the first conductivity-type semiconductor. An active layer is disposed on surfaces of the plurality of nanocores and positioned above the first insulating layer. A second insulating layer is disposed on the first insulating layer and has a plurality of second openings surrounding the plurality of nanocores and the active layer disposed on the surfaces of the plurality of nanocores. A second conductivity-type semiconductor layer is disposed on the surface of the active layer positioned above the second insulating layer.

"The active layer may be disposed on inner side walls of the second openings.

"The second openings may have a diameter greater than that of the first openings, and a portion of the first insulating layer in the perimeter of the first openings may be exposed by the second openings.

"Regions of the nanocores positioned in the second openings may have a sectional area greater than upper and lower regions thereof.

"The inner side walls of the second openings may have an upwardly sloped surface, and an end of the active layer may be positioned on the sloped surface.

"The first and second insulating layers may be made of the same material. The first and second insulating layers may have different etching rates under the same etching conditions. An etching rate of the second insulating layer may be higher than that of the first insulating layer. In order to induce the difference in etching rates, the first and second insulating layers may be made of different materials or may have different air gap densities.

"The second insulating layer may be made of a material obtained by oxidizing a material of the first insulating layer.

"According to another aspect of the present disclosure, there is provided a nano-structure semiconductor light emitting device including a base layer formed of a first conductivity-type semiconductor, and a first insulating layer disposed on the base layer and having a plurality of first openings exposing partial regions of the base layer. A plurality of nanocores is disposed in the exposed regions of the base layer and formed of the first conductivity-type semiconductor. An active layer and a second conductivity-type semiconductor layer are sequentially disposed on surfaces of the plurality of nanocores, and are positioned above the first insulating layer. A second insulating layer is disposed on the first insulating layer and has a plurality of second openings surrounding the plurality of nanocores, the active layer, and the second conductivity-type semiconductor layer sequentially disposed on the surfaces of the plurality of nanocores. An electrode is positioned above the second insulating layer and is connected to the second conductivity-type semiconductor layer.

"The first and second insulating layers may have different etching rates under the same etching conditions. An etching rate of the second insulating layer may be higher than that of the first insulating layer. In order to induce the difference in etching rates, the first and second insulating layers may be made of different materials or may have different air gap densities.

"The second insulating layer may be made of a material obtained by oxidizing a material of the first insulating layer.

"According to another aspect of the present disclosure, there is provided a nano-structure semiconductor light emitting device comprising a base layer formed of a first conductivity type semiconductor and an insulating layer disposed on the base layer and having a plurality of first openings exposing partial regions of the base layer. A plurality of nanocores formed of the first conductivity-type semiconductor is disposed in the exposed regions of the base layer. Outer surfaces of the nanocores are stable crystal planes. An active layer is disposed on the surfaces of the plurality of nanocores and positioned above the insulating layer. A second conductivity-type semiconductor layer is disposed on a surface of the active layer and positioned above the insulating layer.

"The stable crystal planes may be anti-polar or non-polar planes, and the nanocores may be hexagonal pillar-shaped.

"The base layer may comprise a nitride semiconductor satisfying Al.sub.xIn.sub.yGa.sub.1-x-yN (0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, 0.ltoreq.x+y.ltoreq.1).

"The nano-structure semiconductor light emitting device may further comprise a contact electrode filling spaces between adjacent nanocores.

BRIEF DESCRIPTION OF THE DRAWINGS

"The above and other aspects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.

"FIG. 1 is a cross-sectional view of a nano-structure semiconductor light emitting device according to an embodiment of the present disclosure.

"FIG. 2 is a cross-sectional view showing an enlarged portion 'A' in a nano-light emitting structure of the light emitting device illustrated in FIG. 1.

"FIGS. 3A through 3D are cross-sectional views illustrating major processes of a method for manufacturing a nano-structure semiconductor light emitting device in FIG. 1.

"FIG. 4 is a cross-sectional view illustrating a nano-light emitting structure employed in a particular example according to a modification of the present disclosure.

"FIGS. 5A through 5E are cross-sectional views illustrating major processes of a method for manufacturing a light emitting device employing the nano-light emitting structure in FIG. 4.

"FIG. 6 is a cross-sectional view illustrating a nano-light emitting structure employed in another example according to an embodiment of the present disclosure.

"FIGS. 7A through 7C are cross-sectional views illustrating major processes of a method for manufacturing a light emitting device employing the nano-light emitting structure in FIG. 6.

"FIGS. 8A and 8B are cross-sectional views illustrating processes using a different multi-layer mask for obtaining the nano-light emitting structure in FIG. 7C.

"FIG. 9 is a cross-sectional view illustrating a nano-light emitting structure employed in another embodiment of the present disclosure.

"FIGS. 10A through 10F are cross-sectional views illustrating major processes of a method for manufacturing a light emitting device employing the nano-light emitting structure in FIG. 9.

"FIGS. 11A and 11B are schematic views illustrating a thermal annealing process employed in FIG. 10C.

"FIG. 12 is a cross-sectional view illustrating a nano-light emitting structure employed in another embodiment of the present disclosure."

For additional information on this patent application, see: Cha, Nam Goo; Kuh, Bong Jin; Choi, Han Mei. Nano-Structure Semiconductor Light Emitting Device. Filed January 27, 2014 and posted August 7, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5814&p=117&f=G&l=50&d=PG01&S1=20140731.PD.&OS=PD/20140731&RS=PD/20140731

Keywords for this news article include: Semiconductor, Samsung Electronics Co. Ltd..

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Source: Electronics Newsweekly


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