TWI398016B - Photoelectric semiconductor device having buffer layer of iii-nitride based semiconductor and manufacturing method thereof - Google Patents

Description

Photoelectric semiconductor device with three-group nitrogen compound semiconductor buffer layer and method of manufacturing the same

The present invention relates to an optoelectronic semiconductor component having a three-group nitrogen compound semiconductor buffer layer and a method of fabricating the same, and more particularly to an optoelectronic semiconductor component having a tri-group nitrogen compound semiconductor as a buffer layer.

As the light-emitting diode components are widely used in different products, the materials for blue light-emitting diodes have been produced in recent years, and have become an important research and development object of the current optoelectronic semiconductor materials industry. At present, materials for blue light-emitting diodes include zinc selenide (ZnSe), tantalum carbide (SiC), and indium gallium nitride (InGaN). These materials are wide band gap semiconductor materials with a gap of about Above 2.6eV. Since the gallium nitride series is a direct gap luminescent material, it can produce high-intensity illumination light, and has the advantage of longer life than zinc selenide which is also a direct energy gap.

Early research and development for tri-family nitrogen compounds or gallium nitride focused on how to form high-quality gallium nitride thin films. However, due to the lack of a substrate material that matches the lattice constant and the expansion coefficient of gallium nitride, and the formation of a thin film at a very high temperature, it is necessary to grow high-quality gallium nitride crystal under such conditions. Not easy.

S.Yoshida et al. used sapphire as a substrate in 1983, first growing a layer of aluminum nitride (AlN) as a buffer layer at a high temperature, and then growing a gallium nitride film layer thereon, so that a crystal of better quality was obtained. . Later, in 1986, I. Akasa and H. Amano first used organic gold. It is a vapor deposition method (MOCVD) to grow a gallium nitride film layer which is grown at a low temperature by using aluminum nitride as a buffer layer, and then forms a gallium nitride film layer at a high temperature.

In the same year, Nakamura Shuji of Japan's Nichia Chemical Industries invested in the research of gallium nitride materials, first growing a gallium nitride film layer in a two-flow MOCVD reactor, and two on the gallium nitride epitaxial technology. A major change, in which he abandoned the use of gallium arsenide as a buffer layer, and switched to low-temperature-grown gallium nitride as a buffer layer, and the application for this improvement is US Pat. No. 5,290,393. Figure 1 is a schematic cross-sectional view of a light-emitting diode 10 of U.S. Patent No. 5,290,393. A layer of Ga _x Al _x N (0 < x ≦ 1) is formed on the substrate 11 of sapphire as the buffer layer 12 at a temperature lower than 900 ° C and a film thickness of about 0.001 μm to 0.5 μm. A layer of Ga _x Al _x N (0 < x ≦ 1) is then epitaxially grown on the buffer layer 12 as a light-generating semiconductor layer 13 at a temperature between 900 ° C and 1150 ° C.

Figure 2 is a schematic cross-sectional view of a light-emitting diode 20 of U.S. Patent No. 6,847,046. A SiN/Al _1-xy In _x Ga _y N superlattice layer is formed on the sapphire substrate 21 as the buffer layer 22, and then an undoped gallium nitride (GaN) is formed on the buffer layer 22. Layer 23.

Figure 3 is a schematic cross-sectional view of a light-emitting diode 30 of U.S. Patent No. 5,523,589. A layer of Al _x Ga _1-x N or Al _1-xy In _x Ga _y N is formed as a buffer layer 33 on the substrate 32 having conductive tantalum carbide, and then a lower heterostructure layer is formed on the buffer layer 33 (lower) Heterostructure layer)34. Further, the N-type electrode 31 is provided on the bottom of the substrate 32.

Figure 4 is a schematic cross-sectional view of a light-emitting diode 40 of U.S. Patent No. 5,122,845. An aluminum nitride (AlN) layer is formed on the sapphire substrate 41 as the buffer layer 42, and then an N-type gallium nitride (GaN) layer 43 is formed on the buffer layer 42.

The above-mentioned prior art adopts a nitride containing aluminum as a buffer layer. Due to the high hardness of the buffer layer, the lattice between the substrate and the luminescent epitaxial structure is mismatched and cannot be adjusted. Substrate and illuminating The cumulative stress between the crystal structures is not easily eliminated due to the high hardness of the buffer layer, and even the epitaxial structure may be cleaved. In addition, the lattice mismatch and the inability to release the stress cause the epitaxial structure to have a poor discharge defect, that is, the epitaxial structure may deteriorate in quality.

In summary, there is a need in the market for an optoelectronic semiconductor component that ensures stable quality, which can alleviate various shortcomings of the above-mentioned prior art.

The main object of the present invention is to provide an optoelectronic semiconductor component having a three-group nitrogen compound semiconductor buffer layer and a method for fabricating the same, which is a buffer layer between a substrate and a luminescent epitaxial structure. Effectively release accumulated stress to avoid the occurrence of splitting.

Another object of the present invention is to provide an optoelectronic semiconductor component having a buffer group of a trivalent nitrogen compound semiconductor. Since the stress accumulation of the epitaxial layer is reduced, the density of the defective defect in the epitaxial structure can be reduced, thereby improving the optoelectronic semiconductor component. quality.

To achieve the above object, the present invention discloses an optoelectronic semiconductor component having a tri-group nitrogen compound semiconductor buffer layer, comprising a substrate, and at least two In _x Ga _1-x N layers and at least two In _y Ga _1-y N The layers are interleaved on the substrate to form a buffer layer, where x is not equal to y, or 0 < x, y ≦ 1. An epitaxial light emission structure disposed on the upper layer of In _y located on the surface of the Ga _1-y N layer interposed between the In of the substrate and the epitaxial emission structure _x Ga _1-x N layer and said In _y Ga _1-y The N layer forms a superlattice nucleation layer to reduce stress.

The number of layers of the In _x Ga _1-x N layer and the In _y Ga _1-y N layer is preferably between 2 and 5, respectively, and the laminate is a superlattice core layer, and the laminate thickness is 0.001. Mm to 0.5 μm.

The material of the substrate comprises sapphire, tantalum carbide (SiC), tantalum, zinc oxide (ZnO), magnesium oxide (MgO), and gallium arsenide (GaAs).

The optoelectronic semiconductor component is a light emitting diode, a laser diode or a photo sensor.

The present invention further discloses a method of fabricating an optoelectronic semiconductor component having a tri-group nitrogen compound semiconductor buffer layer. First, the purification treatment of the surface of the substrate is performed. An organic metal precursor of ammonia gas and a trivalent element is further introduced to grow a plurality of In _x Ga _1-x N/In _y Ga _1-y N (x≠y) laminates. If the number of repeatedly formed In _x Ga _1-x N/In _y Ga _1-y N(x≠y) stacks is equal to a set value, the luminescent epitaxial structure is further grown in the plurality of In _x Ga _1-x N/ On _y Ga _1-y N(x≠y) laminate, otherwise the step of producing the In _x Ga _1-x N/In _y Ga _1-y N(x≠y) stack is repeated.

The organometallic precursor of the tri-group element is an organometallic compound of gallium or indium, such as trimethylgallium, triethylgallium, trimethylindium, and triethylindium.

The flow rate of the organometallic precursor of the tri-group element is preferably controlled between 50 and 1000 cubic centimeters per minute.

10, 20, 30, 40‧‧‧Lighting diodes

11, 21, 32, 41‧‧‧ substrates

12, 22, 33, 42‧‧‧ buffer layer

13‧‧‧Semiconductor layer

23‧‧‧GaN layer

31‧‧‧N type electrode

34‧‧‧ Lower heterostructure layer

43‧‧‧N-type gallium nitride (GaN) layer

50‧‧‧Optoelectronic semiconductor components

51‧‧‧Substrate

52‧‧‧buffer layer

53‧‧‧N type semiconductor material layer

54‧‧‧ active layer

55‧‧‧P type semiconductor material layer

56‧‧‧N type electrode

57‧‧‧P type electrode

521‧‧‧In _x Ga _1-x N layer

522‧‧‧In _y Ga _1-y N layer

1 is a schematic cross-sectional view of a light-emitting diode 10 disclosed in U.S. Patent No. 5,290,393; FIG. 2 is a schematic cross-sectional view of a light-emitting diode 20 disclosed in U.S. Patent No. 6,847,046; FIG. 3 is a U.S. Patent No. 5,523,589. FIG. 4 is a schematic cross-sectional view of a light-emitting diode 30 disclosed in US Pat. No. 5,122,845; FIG. 5 is an optoelectronic semiconductor of the present invention having a P-type three-group nitrogen compound semiconductor. FIG. 6 is a structural diagram of the manufacture of an optoelectronic semiconductor component having a P-type Group III nitrogen compound semiconductor according to the present invention.

Fig. 5 is a structural view showing an optoelectronic semiconductor device having a P-type Group III nitrogen compound semiconductor according to the present invention. In general, the fabrication of the optoelectronic semiconductor component 50 provides a substrate 51 such as sapphire (i.e., aluminum oxide Al ₂ O ₃ ), niobium carbide (SiC), tantalum, zinc oxide (ZnO), or magnesium oxide ( MgO), gallium arsenide (GaAs), etc., and different material layers are formed on the substrate 51. Since the lattice constant of the substrate 51 and the group III nitrogen compound do not match, it is necessary to form at least two In _x Ga _1-x N layers 521 and at least two In _y Ga _1-y N layers on the substrate 51 first. 522 is interleaved with one of the buffer layers 52. An N-type semiconductor material layer 53 is then grown on the buffer layer 52, which can be used to form an N-type gallium nitride doped germanium film as an N-type semiconductor material layer 53 by epitaxy. Then, an active layer 54 of a multi-layer quantum well structure is grown on the N-type semiconductor material layer 53, for example, a five-layer indium gallium nitride (InGaN)/gallium nitride (GaN) multilayer quantum well structure, and the active layer 54 is a light-emitting diode. Body 50 primarily produces portions of light. Finally, at least one P-type semiconductor material layer 55 is formed on the active layer 54. The P-type semiconductor material layer 55 may be a lamination or doping of magnesium-doped gallium nitride, magnesium-doped gallium nitride and indium gallium nitride. The magnesium-alloyed aluminum gallium and the gallium nitride superlattice structure and the magnesium-doped gallium nitride have different structures. Further, a pattern of the N-type electrode 56 and the P-type electrode 57 is formed in each of the N-type semiconductor material layer 53 and the P-type semiconductor material layer 55, whereby external power can be connected.

The buffer layer 52 is a superlattice core layer having a lower hardness than the conventional aluminum-containing buffer layer, and can effectively reduce the stress accumulated between the substrate and the luminescent epitaxial structure, and the total film thickness is about 0.001 μm to 0.5 μm. . Since the stress accumulation of the crystal lattice is reduced, the density of the defective defects in the epitaxial layer can be lowered, thereby improving the quality of the optoelectronic semiconductor device 50. Further, in the buffer layer 52, x ≠ y, and 0 < x, y ≦ 1, wherein 0 < x, y ≦ 0.5 is preferable.

Fig. 6 is a flow chart showing the manufacture of an optoelectronic semiconductor device having a P-type Group III nitrogen compound semiconductor according to the present invention. As shown in step 61, the surface of the substrate is cleaned, for example, in a hydrogen-filled environment at a temperature of 1200 ° C for thermal cleaning. An organometallic precursor of ammonia and a tri-group element can be introduced, and an organometallic compound of gallium or indium can be used as the organometallic precursor, for example, trimethylgalliaum (TMGa), triethylgallium. And trimethylindium (TMIn) and triethylindium, etc., thereby growing a plurality of In _x Ga _1-x N/In _y Ga _1-y N (x≠y) stacks, as shown in step 62 . The flow rate of trimethylgallium and trimethylindium can be controlled between 50~1000 cubic centimeters per minute (SCCM), and the flow rate of ammonia gas can be controlled at 0.5~200 liters per minute (standard Cubic liter per minute; SCLM). As shown in step 63, if the total number of over _- formed In _x Ga _1-x N/In _y Ga _1-y N (x≠y) stacks is equal to the set value (2 to 5 stacks are preferred, that is, The In _x Ga _1-x N layer and the In _y Ga _1-y N layer are respectively 2 to 5 layers), and then the luminescent epitaxial structure is further grown in the plurality of In _x Ga _1-x N/ according to the instruction of step 64. On _y Ga _1-y N(x≠y) laminate, otherwise step 62 of generating the In _x Ga _1-x N/In _y Ga _1-y N(x≠y) stack is repeated.

The application of the present invention is not limited to the illustrated light emitting diodes, and the related optoelectronic semiconductor components may be covered by the scope of the patent application, for example, a laser diode and a photo sensor.

The technical and technical features of the present invention have been disclosed as above, and those skilled in the art can still make various substitutions and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the present invention should be construed as being limited by the scope of the appended claims

50‧‧‧Optoelectronic semiconductor components

51‧‧‧Substrate

52‧‧‧buffer layer

53‧‧‧N type semiconductor material layer

54‧‧‧ active layer

55‧‧‧P type semiconductor material layer

56‧‧‧N type electrode

57‧‧‧P type electrode

521‧‧‧In _x Ga _1-x N layer

522‧‧‧In _y Ga _1-y N layer

Claims (10)

An optoelectronic semiconductor component having a tri-group nitrogen compound semiconductor buffer layer, comprising: a substrate; a buffer layer having a superlattice core layer structure comprising at least two In _x Ga _1-x N layers and at least two In _y Ga _1-y N layers are interleaved on the substrate, where x is not equal to y, 0 < x, y 0.5 and the total thickness of the buffer layer is 0.001 μm to 0.5 μm; and a luminescent epitaxial structure is provided on the buffer layer. According to the optoelectronic semiconductor component of the trivalent nitrogen compound semiconductor buffer layer of claim 1, the number of layers of the In _x Ga _1-x N layer and the In _y Ga _1-y N layer is between 2 and 5, respectively. An optoelectronic semiconductor component having a three-group nitrogen compound semiconductor buffer layer according to claim 1, wherein the material of the substrate comprises sapphire, lanthanum carbide (SiC), tantalum, zinc oxide (ZnO), magnesium oxide (MgO), and gallium arsenide. (GaAs). The optoelectronic semiconductor component of claim 3, wherein the optoelectronic semiconductor component is a light emitting diode, a laser diode or a photo sensor. A method for manufacturing an optoelectronic semiconductor device having a buffer group of a three-group nitrogen compound semiconductor, comprising the steps of: purifying a surface of a substrate; introducing an organometallic precursor of ammonia gas and a tri-group element to surface of the substrate A buffer layer having a superlattice core layer structure, wherein the buffer layer comprises a plurality of In _x Ga _1-x N/In _y Ga _1-y N stacks, wherein x is not equal to y, 0<x, y 0.5 and the total thickness of the buffer layer is 0.001 μm to 0.5 μm, and the number of layers of the In _x Ga _1-x N layer and the In _y Ga _1-y N layer is between 2 and 5, respectively; An epitaxial structure is on the buffer layer. A method of producing an optoelectronic semiconductor device having a Group III nitrogen compound semiconductor buffer layer according to claim 5, wherein the material of the substrate comprises sapphire, tantalum carbide, niobium, zinc oxide, magnesium oxide, and gallium arsenide. A method of producing an optoelectronic semiconductor device having a three-group nitrogen compound semiconductor buffer layer according to claim 5, wherein the organometallic precursor of the tri-group element is an organometallic compound of gallium or indium. A method of producing an optoelectronic semiconductor device having a three-group nitrogen compound semiconductor buffer layer according to claim 7, wherein the organometallic compound of gallium or indium comprises trimethylgallium, triethylgallium, trimethylindium, and triethylindium . A method of producing an optoelectronic semiconductor device having a three-group nitrogen compound semiconductor buffer layer according to claim 5, wherein the flow rate of the organometallic precursor of the tri-group element is controlled to be between 50 and 1000 cubic centimeters per minute. A method of manufacturing an optoelectronic semiconductor device having a three-group nitrogen compound semiconductor buffer layer according to claim 5, wherein the flow rate of the ammonia gas is controlled to be between 0.5 and 200 liters per minute.