TW200306674A - Light-emitting diode structure with selective growth - Google Patents

Abstract

A light-emitting diode structure with selective growth is disclosed, which is to grow an oxide layer on the substrate surface, pattern the oxide layer, form the buffer layer selectively on the oxide layer using the lateral growth technology, then grow an n-type GaN layer, an active layer, and a p-type GaN layer sequentially on the buffer layer, and fabricate the electrode to complete the structure of light-emitting diode.

Description

200306674 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to the structure of a light-emitting diode element, and particularly to a light-emitting diode structure that generates a gallium nitride epitaxial layer by a lateral growth technique. 0 [Prior art] A gallium nitride-based compound semiconductor that is conventionally used in light-emitting structures such as light-emitting diodes (LEDs) or laser diodes (LDs) is usually achieved by growing on a sapphire substrate. However, The lattice mismatch (1 a 11 icemismatch) of sapphire nitride and sapphire substrate is about 16%, so the defect density of the gallium nitride-based compound-semiconductor grown on the sapphire substrate is approximately per square. 1 09 cm / cm2, thus affecting the reliability and performance of the light emitting device. Based on the above problems, the Republic of China Patent No. 50 1 2 8 9 discloses a lateral overgrowth (EL0) stupid crystal method, which mainly aligns the vertical difference (the direction of the vertical substrate) caused by the lattice mismatch. The over-growth technology guides the difference rows propagating in the vertical direction to the lateral direction, thereby improving the defect density in the vertical direction. In addition, since the sapphire substrate and the gallium nitride-based compound semiconductor have high hardness, it is difficult to use a diamond cutter when cutting a light-emitting device that has completed a wafer process into crystal grains, so that a well-shaped crystal is cut. grain. Therefore, the wafer must be ground to a corpse size of about 85 microns, and an isolation (3301 & 1101) process must be added to the wafer process to help improve the cutting yield. The know-how is still there and requires additional use

200306674 V. Description of the invention (2) --- Using the isolation process to help raise the problem of cutting yield in%. [Summary of the Invention] In view of the above-mentioned fabrication of gallium nitride, the main purpose of the present invention is to form a pattern separation process for the buffer layer, and directly use the horizontal growth of the row to generate a parasitic capacitance value of the manufacturing process of another aspect of the present invention. Let the specific embodiment% described in the present invention, the present invention discloses a light structure using lateral growth technology. On the surface of the silicon dioxide layer where the epitaxial growth of the light-emitting diode structure grows, there is no need to use an additional change in the mixing ratio of the growth gas and the #etch gas, and a buffer layer conforming to the pattern is required.

What is achieved is the simplification of the light-emitting diode process by the lateral growth technology, and thus the present invention has-compared with the conventional technology-and obtains significantly improved luminous efficiency. The purpose and advantages are more obvious. The following will be explained in detail and with drawings. [Embodiment] Two polar books! In the illustrated embodiment, a selective growth luminescent phase deposition (ΜοϋΛ). The substrate 1 is placed in a gold organic chemical vapor silicon carbide (Sic) stone / r system. The substrate 1 may be sapphire, π · Α1η ^), Xi (Si), gallium arsenide (GaAs), lithium metaaluminate in hot: ιΛ record #acid lithium (LiGa02) and aluminum nitride (A1N) one of the materials. After that, 7-sticules were produced, and the thin film of the silicon dioxide compound was deposited as the oxide layer 2, 2 [) ^ pattern of the silicon monoxide film to form a plurality of non-adjacent independent regions '2 2' and a plurality of blocks 2 0, 2 2 has a gap a between each other, and the block

200306674 V. Description of the invention (3) 20 and 22 have their respective lateral widths b and c. The lateral widths b and c can be divided into large widths and small widths. The lateral widths of large widths are more than 30 microns and the lateral widths of small widths. The width c is less than 5 microns, and the gap a is between 8 and 12 microns, preferably 10 microns. This figure is a schematic diagram of a selective growth light-emitting structure buffer layer, an n-type gallium nitride layer, an active layer, and a p-type nitride layer according to an embodiment of the present invention. Angular growth technology (1 atera 1 gr 〇wth), to make better selective growth of gallium nitride (GaN) series of compounds by using a gas mixture to grow under $ pressure, adjust hydrogen (H2), ammonia (NH3) Trimethylgallium

Tr * iraethyl GaUium 'TMG), and its special mixing ratio can affect the selection ratio, and etch away any nitride that has just grown in the oxide layer 2 m, as in the horizontal section of the independent block 20 in the oxide layer 2. ; Because of the small width, it is necessary to split two branches of two hearts and two separate branches to a width of ㈣ and separate adjacent iwy layers to form a single body, which can form a compound with ^ = gallium. Buffer layer 3, and oxide layer 2 which is not adjacent to independent block 22 in the growth process: active layer 5 and P-type gallium nitride layer 6. η-type & gallium nitride; ^ 'Gallium nitride layer 4, the family compound to hide inflammation + π 1 糸 gallium nitride-based π gallium nitride-based two main components, P-type gallium nitride layer 6 material Mg Prostitutes 111 ~ V Conghua Iridium πΐ-V compound. 4 Bamboo-based magnesium doping. The third figure is an embodiment of the present invention, in which a P-type gallium nitride layer is etched in a polar structure, a light-emitting layer with main k-type growth, and n-type nitride;

200306674 V. Schematic diagram of invention description (4). After the formation of the p-type gallium nitride layer 6 in the second figure, a portion of the p-type gallium nitride layer 6, the active layer 5 and the n-type gallium nitride layer 4 are etched by dry etching technology to facilitate the n-type gallium nitride layer. Layer 4 forms an exposed area, and a metal titanium / metal (T i / A 1) is deposited on the surface of the exposed area to form an η-type ohmic contact electrode. The fourth figure is a selective growth light emitting device according to an embodiment of the present invention. Schematic diagram of p-type ohmic contact electrode with polar structure. The ρ-type ohmic contact electrode 8 is formed on the ρ-type gallium nitride layer 6. In order to promote the light-emitting diode structure to maintain good luminous efficiency, the ρ-type ohmic contact electrode 8 is usually made very thin. It is made of nickel / gold beryllium (Ni / AuBe), and the thickness of the p-type ohmic contact electrode 8 is between 50 and 200 angstroms (A), and the preferred value is i 00 angstroms (magic. The fifth figure is based on The embodiment of the present invention is a schematic view of a selective growth pad structure with a polar body structure. A plurality of pads 9, x are formed in the n-type ohmic contact electrode 7 and the type ^ ^ ^ ^ ^ ^ ^ ^ / wire formation Electrical connection and welding: contact the electrode 8 so as to be a stacked layer with the conductive plate pad 9 and continue to spread the crystalline metal titanium / surface / shao / titanium / gold (Ti / pt, layer / pile layer) It is formed by 5 layers ranging from 3 micrometers to 1 micrometer ("m) 1 Au), and the thickness is completed as described above. The thickness is 2 micrometers (" m). The grain structure is shown in Figure 1. Figure 1 shows the luminous efficiency of a real boat diode structure according to the present invention, a selective growing luminous flux (unit: milliampere). Second graph comparing the electrical injection rate (unit: au), then ^ = contact which is depicted in the embodiment corresponds to the optical output power than that of the conventional art is connected to a line = visible embodiments of the present invention While the present invention It ’s better to compare with the rate. Pregnancy Jiaguan ’s example reveals the way as above, but it is not used to

200306674 V. Description of the invention (5) The invention is limited. Anyone familiar with this technology can make any modification and retouching without departing from the spirit and scope of the invention, and the various changes and retouchings that he or she does still remain. The invention is defined by the scope of patent application.

Page 8 200306674 Brief description of the diagram The first diagram is a schematic diagram of a selectively grown light-emitting diode structure oxide layer according to an embodiment of the present invention The second diagram is a selectively grown light-emitting diode according to an embodiment of the present invention Schematic diagram of structure buffer layer, n-type GaN layer, active layer and p-type GaN layer. The third figure is a schematic diagram of a selectively grown light emitting diode structure etching part of a P-type gallium nitride layer, an active layer, and an n-type gallium nitride layer according to an embodiment of the present invention. The fourth figure is a schematic diagram of a selectively grown light emitting diode structure P-type ohmic contact electrode according to an embodiment of the present invention. The fifth figure is a schematic diagram of a selective I-length light emitting diode structure welding pad according to an embodiment of the present invention. The sixth diagram is a comparison diagram of the luminous efficiency of a selectively grown light emitting diode structure and the conventional technique according to an embodiment of the present invention. [Description of component symbols] 1 substrate 2 oxide layer 2 0 independent blocks + 2 2 independent blocks a gap b lateral width c lateral width

Page 9 200306674 Brief description of the drawings 3 Buffer layer 4 η-type GaN layer 5 Active layer 6 ρ-type GaN layer 7 η-type ohmic contact electrode 8 ρ-type ohmic contact electrode 9 Welding pad iimii Page 10 Φ

Claims (1)

200306674 6. Scope of patent application1. A selective growth light-emitting diode structure, including: a substrate, the substrate is non-conductive; an oxide layer is deposited on the substrate, and a plurality of patterns are formed after patterning; Non-adjacent independent blocks, the plurality of blocks have respective lateral widths, and the plurality of blocks have a gap between each other. The lateral width can be divided into a large width and a small width, and the large width is above 30 microns. The small width is less than 5 micrometers, the gap is between 8 and 12 micrometers, and the composition of the oxide layer is a silicon dioxide compound; a buffer layer is based on a lateral growth technique, and has a plurality of small After the lateral width of the oxide layer is formed without deposition on adjacent independent blocks, it is connected into a body. The material is mainly a gallium nitride series IE-V group ^ compound; -n-type gallium nitride layer is formed on the On the buffer layer; an active layer 'is formed on the n-type gallium nitride layer, which is composed of a gallium nitride series III-V group compound as a main component; a pY gallium nitride layer is formed on the active layer; A The ohmic contact electrode is formed on an n-type electrode formation region. The n-type electrode formation region is located on the n-type gallium nitride layer. The n-type electrode formation region is formed by etching the p-type gallium nitride layer, the active Layer and the n-type gallium nitride layer, obtained after exposing the n-type gallium nitride layer, and a metal titanium / aluminum: T i / A 1) is deposited on the surface of the n-type gallium nitride layer to form the n Plastic ohmic contact electrode; an ohmic contact electrode formed on the p-type gallium nitride layer, the material of which is nickel / gold beryllium (N i / AuBe), and the thickness of the p-type ohmic contact electrode is between 50 and 20 0 Angstroms (A); and 200306674