Compound semiconductor light-emitting device
An object of the present invention is to provide a compound semiconductor light-emitting device having side surfaces of large surface area to improve the efficiency for outwardly transmitting the emitted light. Another object of the present invention is to provide a technology capable of easily forming the side surfaces with large surface area without using a cutting tool and without the need of taking a trouble to impart mechanical damage. The inventive compound semiconductor light-emitting device has a light-emitting layer, on a substrate, wherein at least a part of a substrate portion of the device side surface has recessed portions in a side direction of the device. The inventive method of producing compound semiconductor light-emitting device comprises the steps of: (a) forming a compound semiconductor layer including a light-emitting layer of an n-type or p-type compound semiconductor on a wafer that serves as a substrate, (b) arranging a negative electrode and a positive electrode at predetermined positions for passing a drive current through the light-emitting layer, (c) forming a separation zone for separating the individual light-emitting devices, (d) perforating many small holes linearly in the wafer that serves as the substrate along the separation zone, and (e) dividing the wafer into individual light-emitting devices along the separation zone.
1. A compound semiconductor light-emitting device comprising:
a substrate having an upper surface, a lower surface, and a plurality of device side surfaces; and
a light-emitting layer grown on the upper surface of said substrate,
wherein at least one of the device side surfaces has an array of recessed portions, individual ones of the recessed portions extend from the lower surface to the upper surface of the substrate, and individual ones of the recessed portions have a semi-circular shape in cross section parallel to the upper surface of the substrate, and
wherein the depth of individual ones of the recessed portions is a radius of the semi-circular shape in a direction parallel to the upper surface of the substrate, and the height of individual ones of the recessed portions from the lower surface to the upper surface of the substrate is at least 20 μm, and wherein a distance of 4 to 40 μm is maintained between adjacent recessed portions in the array of the recessed portions.
2. A light-emitting device according to claim 1 , wherein the light-emitting layer comprises an n-type or p-type compound semiconductor and is of the pn junction type.
3. A light-emitting device according to claim 1 , wherein the substrate is selected from the group consisting of a sapphire, a SiC and a III-V Group compound semiconductor single crystal.
4. A light-emitting device according to claim 1 , wherein the depth of individual ones of the recessed portions is 0.5 to 10 μm.
5. A light-emitting device according to claim 1 , wherein the compound semiconductor light-emitting device is of the flip-chip type.
6. A lamp comprising a compound semiconductor light-emitting device of claim 1 .
7. A source of light comprising a lamp of claim 6 .