TWI396308B - Light emitting device and method of manufacturing the same - Google Patents

Description

Light emitting device and method of manufacturing same

The present invention relates to a light-emitting device and a method of fabricating the same, and more particularly to an infrared light-emitting device and a method of fabricating the same.

Infrared light emitting devices are mainly used in the optical communication industry. The current infrared light-emitting device can be completed only by a few methods, for example, by epitaxial technology, and is fabricated using a semiconductor element (Group III-V element) as a raw material. However, medium and long wavelength infrared light components must be fabricated at low temperatures, so expensive refrigeration equipment is required. Alternatively, conventional infrared light elements require the use of a multilayer film structure to increase process complexity. In addition, the ratio of the full width at half maximum (FWHM) Δλ to the peak wavelength (Peak) λ (Δλ/λ) of the infrared light element is not ideal.

Please refer to FIG. 1A, FIG. 1B and FIG. 2 . FIG. 1A is a schematic diagram of a prior art infrared light emitting device 1 , and FIG. 1B is a top view of the infrared light emitting device 1 in FIG. 1A . 2 is a spectrum diagram of the infrared light emitting device 1 in FIG. 1A. The infrared light emitting device 1 shown in Fig. 1A is disclosed by El-Kady et al., "Photonics and Nanostructures-Fundamentals and Applications", Volume 1, Issue 1, 69-77 (2003). El-Kady et al. used a photo process to create a periodic photoresist on the surface of the germanium substrate 10. Next, a metal 12 and a protective layer (such as graphite) are deposited on the surface of the ruthenium substrate 10, and the ruthenium substrate 10 is etched into a hole of 5 μm deep by a deep reactive ion etching technique to obtain a periodic surface structure ( Periodic surface texture). The black body radiation source of the hole can be coupled to the photon to form a surface plasmon (SP). As shown in Fig. 2, the ratio of the full width at half maximum (Δλ) to the peak wavelength (λ) (Δλ/λ) is about 11.9%. However, such ratios are not sufficient for certain applications. Therefore, how to develop an infrared light-emitting element that can operate at a high temperature and has a ratio (Δλ/λ) of a low half-height width (Δλ) to a peak wavelength (λ) is one of the problems that the industry has solved.

In view of this, the present invention relates to an effective regulation of a waveguide mode of a dielectric layer by designing different dielectric layer thicknesses, so that the light-emitting device can be operated at a high temperature and can emit a narrow bandwidth. Infrared light.

According to an aspect of the invention, a lighting device is proposed for generating infrared light. The light emitting device includes a substrate, a first metal layer, a dielectric layer, and a second metal layer. The substrate has a first surface. The first metal layer is formed on the first surface of the substrate. The dielectric layer is formed on the first metal layer, and the thickness of the dielectric layer is greater than a specific value. A second metal layer is formed on the dielectric layer. When the illuminating device is heated, the dielectric layer has a waveguide mode such that infrared light generated by the illuminating device is transmitted in the dielectric layer, and the wavelength of the infrared light generated in the waveguide mode is It is related to the thickness of the dielectric layer.

According to another aspect of the present invention, a method of fabricating a light emitting device is provided. This illuminating device is used to generate infrared light. This method includes the following steps. A substrate is provided, the substrate having a first surface. Forming a first metal layer on the first surface of the substrate. A dielectric layer of a particular thickness is formed over the first metal layer. A second metal layer is formed on the dielectric layer. When the illuminating device is heated, the dielectric layer has a waveguide mode such that the infrared light generated by the illuminating device is transmitted in the dielectric layer, and the wavelength of the infrared light generated in the waveguide mode and the thickness of the dielectric layer Related.

According to a further aspect of the invention, a lighting device is proposed for generating infrared light. The light emitting device includes a substrate, a first metal layer, a dielectric layer, and a second metal layer. The substrate has a first surface. The first metal layer is formed on the first surface of the substrate. The dielectric layer is formed on the first metal layer, and the thickness of the dielectric layer is less than a specific value. A second metal layer is formed on the dielectric layer. The second metal layer has at least one first hole.

In order to make the above-mentioned contents of the present invention more comprehensible, the following specific embodiments, together with the drawings, are described in detail below:

The present disclosure proposes a light emitting device and a method of fabricating the same. A light emitting device is used to generate infrared light. The light emitting device includes a substrate, a first metal layer, a dielectric layer and a second metal layer. The substrate has a first surface. The first metal layer is formed on the first surface of the substrate. The dielectric layer is formed on the first metal layer, and the thickness of the dielectric layer is greater than a specific value. A second metal layer is formed on the dielectric layer. When the illuminating device is heated, since the thickness of the dielectric layer is greater than a specific value, the dielectric layer has a waveguide mode, and the infrared light generated by the illuminating device can be transmitted in the dielectric layer. Furthermore, the wavelength of the infrared light generated by the waveguide mode of the dielectric layer can be adjusted by the thickness of the modulation dielectric layer. That is, the wavelength of the infrared light generated by the waveguide mode of the dielectric layer is related to the thickness of the dielectric layer.

First embodiment

Please refer to FIG. 3, which is a schematic diagram showing a first embodiment of a light emitting device according to the present disclosure. As shown in FIG. 3, the light emitting device 20 includes a substrate 210, a first metal layer 230, a dielectric layer 250, a second metal layer 270, and a third metal layer 290. The substrate 210 has a first surface 211. The first metal layer 230 is formed on the first surface 211 of the substrate 210. A dielectric layer 250 is formed on the first metal layer 230. The thickness of the dielectric layer 250 is greater than a specific value, such as 1 micrometer (μm). The second metal layer 270 is formed on the dielectric layer 250. The second metal layer 270 has a specific thickness, for example, about 3 to 40 nanometers (nm).

The first metal layer 230 functions as a background radiation suppression layer and an infrared light reflection layer, and has a function of suppressing background radiation from the substrate 210 and reflecting infrared light generated by the dielectric layer 250. Since the thickness of the second metal layer 270 of the embodiment is thin enough, the infrared light generated by the dielectric layer 250 is partially reflected by the second metal layer 270 and partially penetrates the second metal layer 270.

In the present embodiment, the third metal layer 290 serves as a heating source for the conduction of the current of the light-emitting device 20. When the third metal layer 290 is energized, the light emitting device 20 is heated. When the illuminating device 20 is heated, the background radiation from the substrate 210 is blocked by the first metal layer 230, and the first metal layer 230 itself has a small emissivity and does not generate much thermal radiation. Moreover, since the thickness of the dielectric layer 250 is greater than a specific value, the dielectric layer 250 has a waveguide mode. The thermal radiation of the dielectric layer 250 is confined to and oscillated in the first metal layer 230 and the second metal layer 270 and transmitted in the dielectric layer 250. After the dielectric layer 250 absorbs the thermal radiation, the electrons of the dielectric layer 250 will transition from the outer rail domain to the inner rail domain, and the thermal radiation will be converted into light energy. The thermal radiation of the dielectric layer 250 is repeated as a result of the transmission and resonance in the dielectric layer 250 such that the intensity of light at a particular infrared light wavelength is greatly increased.

In more detail, the substrate 210 may be a conductor substrate, an insulating substrate, or a semiconductor substrate. The material of the first metal layer 230 is selected from the group consisting of gold (Au), silver (Ag), and a combination of metals and combinations of reflectance and emissivity in the mid-infrared band of 0.5 to 1 and 0 to 0.5, respectively. group. The material of the dielectric layer 250 may be an oxide (Oxide), a nitride (Nitride), or other dielectric material or insulating material. The second metal layer 270 is at least one of silver (Ag) and a metal having a reflectance of 0.5 to 1 in the mid-infrared light band. The third metal layer 290 contains at least one of molybdenum (Mo) metal and a metal having an electrical conductivity of 10 ³ to 6 x 10 ⁵ (1/cm-ohm).

In the embodiment, the third metal layer 290 is formed on the second surface 213 of the substrate 210, wherein the second surface 213 is opposite to the first surface 211. However, the third metal layer 290 is not limited to be formed on the second surface 213 of the substrate 210, and may be formed between the substrate 210 and the first metal layer 230. Alternatively, the third metal layer 290 may be directly replaced by the first metal layer 230 as a heating source, or the substrate 210 may be directly heated without using the third metal layer 290.

Since the dielectric layer 250 has a waveguide mode by allowing the thickness of the dielectric layer 250 to have a specific value, the infrared light energy generated when the light-emitting device is heated is transmitted in the dielectric layer 250. . Moreover, as a result of the infrared light repeatedly transmitting and resonating in the dielectric layer 250, infrared light having a ratio of a half-height width (Δλ) to a peak wavelength (λ) (Δλ/λ) of about 3% can be obtained, which is superior to The ratio of the full width at half maximum and the peak wavelength of the infrared light emitting device 1 shown in Figs. 1A and 1B. In addition, in this embodiment, the purpose of adjusting the wavelength of the infrared wave can be achieved by adjusting the thickness of the dielectric layer.

Referring to FIGS. 4A to 4E, an example of a method of manufacturing the light-emitting device 20 of the first embodiment is shown. This method includes the following steps. First, as shown in FIG. 4A, a substrate 210 is provided. Next, as shown in FIG. 4B, a first metal layer 230 is formed on the first surface 211 of the substrate 210, and the first metal layer 230 is formed, for example, by a Vapor deposition process. The thickness of the first metal layer 230 may be 100 nanometers (nm), but is not limited thereto. Next, as shown in FIG. 4C, a dielectric layer 250 having a thickness greater than a specific value is formed on the first metal layer 230, for example, a dielectric layer 250 is formed by an evaporation process, but is not limited thereto. Next, as shown in FIG. 4D, the second metal layer 270 is formed on the dielectric layer 250, for example, the second metal layer 270 is formed by an evaporation process, but is not limited thereto. Finally, as shown in FIG. 4E, the third metal layer 290 is formed on the second surface 213 of the substrate 210 opposite to the first surface 211, for example, by forming a third metal layer 290 by an evaporation process, but not limited thereto. Or forming a third metal layer 290 between the first surface 211 of the substrate 210 and the first metal layer 230 (not shown). The thickness of the third metal layer 290 may be 300 nm, but is not limited thereto.

Second embodiment

Please refer to FIG. 5, which is a schematic view showing a second embodiment of a light-emitting device according to the present disclosure. As shown in FIG. 5, the light emitting device 30 includes a substrate 310, a first metal adhesion layer 320, a first metal layer 330, a second metal adhesion layer 340, a dielectric layer 350, a second metal layer 370, and a third metal layer 390. . The illuminating device 30 of the present embodiment is different from the illuminating device 20 of the first embodiment in that the illuminating device 30 of the present embodiment further includes a first metal adhesive layer 320 and a second metal adhesive layer 340. As shown in FIG. 5 , the first metal adhesion layer 320 is formed between the substrate 310 and the first metal layer 330 , and the second metal adhesion layer 340 is formed between the first metal layer 330 and the dielectric layer 350 .

If the physical properties of the first metal layer 330 and the substrate 310, such as the bonded strength, are too small, the first metal layer 330 is directly formed on the substrate 310, which may result in poor robustness to each other. Therefore, the first metal adhesion layer 320, which is physically between the substrate 310 and the first metal layer 330, can be added between the first surface 311 of the substrate 310 and the first surface 331 of the first metal layer 330. Firmness. Similarly, selecting a second metal adhesion layer 340 having a physical property between the first metal layer 330 and the dielectric layer 350 may increase the first surface 332 of the first metal layer 330 and the first of the dielectric layer 350. The firmness of the surface 351. Thus, when the light-emitting device 30 is heated to a high temperature, the probability of occurrence of peeling between the substrate and the first metal layer or between the first metal layer and the dielectric layer can be greatly reduced.

The material of the first metal adhesion layer 320 and the second metal adhesion layer 340 is selected from a transition metal having a surface bonding strength of more than 20 MPa, such as titanium (Ti) or chromium (Cr). A group consisting of tantalum (Ta) and zirconium (Zr) and the like, and a metal having a surface bonding strength greater than that of gold (Au) and cerium oxide (SiO ₂ ) and combinations thereof.

Third embodiment

Please refer to FIG. 6A, which is a schematic diagram of a third embodiment of a light-emitting device 40 according to the present disclosure, and FIG. 6B is a top view of the light-emitting device 40 of FIG. 6A. As shown in FIG. 6A, the light emitting device 40 includes a substrate 410, a first metal adhesion layer 420, a first metal layer 430, a second metal adhesion layer 440, a dielectric layer 450, a second metal layer 470, and a third metal layer 490. . The illuminating device 40 of the present embodiment is different from the illuminating device 30 of the second embodiment in that the second metal layer 470 of the embodiment has at least one hole. As shown in FIGS. 6A and 6B, the present embodiment is described by taking a plurality of holes 471 of the second metal layer 470 as an example.

Since the second metal layer 470 has at least one hole 471, the infrared light transmitted in the waveguide mode of the dielectric layer 450 can be penetrated through the hole 471 when the light emitting device 40 is heated. Therefore, the thickness of the second metal layer 470 of the present embodiment is not limited by a specific range. Furthermore, the at least one hole 471 can be formed by Lithography.

Moreover, since the second metal layer 470 has at least one hole 471, when the light-emitting device 40 is heated, the interface between the dielectric layer 450 and the second metal layer 470, and the interface between the second metal layer 470 and the air interface are also induced. Surface plasma mode. That is, when the light emitting device 40 is heated, the dielectric layer 450 has two modes, one is a surface plasma mode and the other is a waveguide mode. The infrared light generated by the waveguide mode is related to the thickness of the dielectric layer 450, and in the surface plasma mode, the interface between the dielectric layer 450 and the second metal layer 470, and the second metal layer 470 and air. The electric field vibration near the interface (Oscillation) to generate infrared light. Since the frequency of the electric field vibration is related to the arrangement period of the holes, the infrared light generated by the surface plasma mode is related to the arrangement period of the holes 471 of the second metal layer 470. Therefore, by reducing the arrangement period of the holes 471, the wavelength of the infrared light generated by the surface plasma mode is reduced, and the infrared light generated by the surface plasma mode and the wavelength of the infrared light generated by the waveguide mode are reduced. different.

Please refer to FIG. 7, which shows a spectrogram of the light-emitting device of FIG. 6A. When the third metal layer 490 is energized, the light-emitting device 40 is heated, and the spectrum of the light emitted by the light-emitting device 40 can be measured as shown in FIG. In FIG. 7, the wavelength of the infrared light generated by the basic mode of the waveguide mode of the dielectric layer 450 corresponds to the wavelength of the infrared light indicated by the hollow square shape, and the surface plasma mode of the dielectric layer 450 is generated. The wavelength of the infrared light corresponds to the wavelength of the infrared light indicated by the diamond. As shown in FIG. 7, when the thickness of the dielectric layer 450 is gradually increased from 1.1 μm to 2.6 μm, the wavelength of the infrared light generated by the basic mode of the waveguide mode of the dielectric layer 450 is far from the surface of the dielectric layer 450. The wavelength of the infrared light produced by the slurry mode. Therefore, the wavelength of the generated infrared light can be adjusted by designing the thickness of the different dielectric layer 450.

As a result of actual experiments, as shown in FIG. 8, the ratio of the full width at half maximum (Δλ) of the infrared light generated by the light-emitting device of the present embodiment to the peak wavelength (λ) (Δλ/λ) can be reduced to about 3%. . Thereby, the present embodiment can provide an infrared light source that can operate at a high temperature and has a narrow frequency band.

Fourth embodiment

Please refer to FIG. 9, which is a schematic view showing a fourth embodiment of a light-emitting device according to the present invention. As shown in FIG. 9, the light emitting device 50 includes a substrate 510, a first metal layer 530, a dielectric layer 550, a second metal layer 570, and a third metal layer 590. The illuminating device 50 of the present embodiment is different from the illuminating device 20 of the first embodiment in that the thickness of the dielectric layer 550 of the present embodiment is less than a specific value, and the second metal layer 570 has at least one hole 571. As shown in FIG. 9, the present embodiment is described by taking a plurality of holes 571 of the second metal layer 570 as an example.

Other embodiments of the present disclosure provide infrared light by virtue of the thickness of the dielectric layer being greater than a particular value such that the dielectric layer has a waveguide mode. In contrast, in the present embodiment, by reducing the thickness of the dielectric layer, the infrared light generated by the light-emitting device is generated by the surface plasma mode.

In the present embodiment, the dielectric layer 550 and the second metal layer 570 generate a surface plasma modality and are coupled to the first metal layer 530 by the thickness of the dielectric layer 550 being less than a specific value, for example, 500 nm. As shown in FIG. 10, the smaller the thickness of the dielectric layer 550, the surface plasma mode generated by the dielectric layer 550 and the second metal layer 570 and the surface electrical power generated by the induced dielectric layer 550 and the first metal layer 530. The stronger the slurry mode coupling, the more the refractive index of the dielectric layer 550 changes, which in turn affects the wavelength of the light. More specifically, the wavelength of the light is related to the refractive index of the period and dielectric layer 550. As shown in FIG. 11, when the thickness of the dielectric layer 550 is close to 100 nm, the ratio of the full width at half maximum (Δλ) of the infrared light generated by the surface plasma mode to the peak wavelength (λ) (Δλ/λ) is about 10%. It is also superior to the ratio of the full width at half maximum to the peak wavelength of the infrared light emitting device 1 shown in FIGS. 1A and 1B.

In conclusion, the present invention has been disclosed in the above embodiments, but it is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

1. . . Infrared light emitting device

10. . .矽 substrate

12. . . metal

14. . . The protective layer

20, 30, 40, 50. . . Illuminating device

210, 310, 410, 510. . . Substrate

211, 311. . . First surface of the substrate

213. . . Second surface of the substrate

230, 330, 430, 530. . . First metal layer

250, 350, 450, 550. . . Dielectric layer

270, 370, 470, 570. . . Second metal layer

290, 390, 490, 590. . . Third metal layer

331. . . First surface of the first metal layer

332. . . Second surface of the first metal layer

351. . . First surface of the dielectric layer

471, 571. . . Hole

Fig. 1A is a schematic view showing a prior art infrared light emitting device.

Fig. 1B is a top view showing the infrared light emitting device in Fig. 1A.

Fig. 2 is a spectrum diagram showing the infrared light emitting device in Fig. 1A.

Figure 3 is a schematic view showing a first embodiment of the light-emitting device of the present disclosure.

4A to 4E are views showing a manufacturing process of the light-emitting device of the first embodiment.

Figure 5 is a schematic view showing a second embodiment of the light-emitting device of the present disclosure.

Figure 6A is a schematic view showing a third embodiment of the light-emitting device of the present disclosure.

Fig. 6B is a top view showing the illuminating device of Fig. 6A.

Figure 7 is a diagram showing the spectrum of the light-emitting device of Figure 6A.

Figure 8 is a diagram showing another spectrum of the light-emitting device of Figure 6A.

Figure 9 is a schematic view showing a fourth embodiment of the light-emitting device of the present disclosure.

Figure 10 is a graph showing the change of surface plasma coupling to the refractive index of the dielectric layer when the light-emitting device of Figure 9 is at different dielectric layer thicknesses.

Figure 11 is a diagram showing the spectrum of the light-emitting device of Figure 9.

20. . . Illuminating device

210. . . Substrate

211. . . First surface of the substrate

213. . . Second surface of the substrate

230. . . First metal layer

250. . . Dielectric layer

270. . . Second metal layer

290. . . Third metal layer

Claims (19)

A light emitting device for generating infrared light includes: a substrate having a first surface; a first metal layer formed on the first surface of the substrate; and a dielectric layer ( a dielectric layer formed on the first metal layer, the dielectric layer having a thickness greater than a specific value; and a second metal layer formed on the dielectric layer; wherein, when the light emitting device is heated, The dielectric layer has a waveguide mode such that infrared light generated by the light emitting device is transmitted in the dielectric layer, and the wavelength of the infrared light generated in the waveguide mode is related to the thickness of the dielectric layer . The illuminating device of claim 1, further comprising a first metal adhesive layer and a second metal adhesive layer, the first metal adhesive layer being formed between the substrate and the first metal layer, the first a second metal adhesion layer is formed between the first metal layer and the dielectric layer, and the material of the first metal adhesion layer and the second metal adhesion layer is selected from a surface bonding strength greater than 20 megapascals (Mpa). A transition metal and a group having a surface bonding strength greater than that of gold (Au) and cerium oxide (SiO2) and combinations thereof. The illuminating device of claim 1, further comprising a third metal layer formed between the substrate and the first metal layer or a second surface of the substrate, the second surface The first surface is opposite. The illuminating device of claim 3, wherein the third metal layer comprises at least molybdenum (Mo) metal and a metal having an electrical conductivity of 10 ³ to 6×10 ⁵ (1/cm-ohm) One of them. The illuminating device of claim 1, wherein the material of the first metal layer is selected from the group consisting of gold (Au), silver (Ag), and reflectance and emissivity in the mid-infrared band of 0.5 to 1 respectively. And a group of metals from 0 to 0.5 and combinations thereof. The illuminating device of claim 1, wherein the second metal layer has a thickness of about 3 to 40 nanometers (nm). The illuminating device of claim 1, wherein the second metal layer has at least one first hole, and the at least one first hole causes the dielectric layer to have a surface plasma when the illuminating device is heated In the modality, the wavelength of the infrared light generated in the surface plasma mode is different from the wavelength of the infrared light generated in the waveguide mode. The illuminating device of claim 1, wherein the second metal layer comprises at least one of silver (Ag) and a metal having a reflectance of 0.5 to 1 in the mid-infrared light band. The light-emitting device according to claim 1, wherein the substrate is a conductor substrate, an insulating substrate or a semiconductor substrate. A method of manufacturing a light emitting device for generating infrared light, the method comprising: providing a substrate having a first surface; forming the first metal layer on the first of the substrate Forming a dielectric layer of a specific thickness on the first metal layer; and forming a second metal layer on the dielectric layer; wherein, when the light emitting device is heated, the dielectric The layer has a waveguide mode such that infrared light generated by the illumination device is transmitted in the dielectric layer, and the wavelength of the infrared light generated in the waveguide mode is related to the thickness of the dielectric layer. The method of claim 10, further comprising: forming a first metal adhesion layer between the substrate and the first metal layer; and forming a second metal adhesion layer formed on the first metal layer Between the dielectric layers. The method of claim 10, wherein the first metal layer is formed on the first surface of the substrate by a vapor deposition process. The method of claim 10, wherein the dielectric layer is formed on the first metal layer by an evaporation process. The method of claim 10, wherein the second metal layer has at least one first hole. The method of claim 14, wherein the at least one first hole of the second metal layer is formed by lithography, and the at least one first hole is made when the light emitting device is heated. The dielectric layer has a surface plasma mode, and the wavelength of the infrared light generated in the surface plasma mode is different from the wavelength of the infrared light generated in the waveguide mode. The method of claim 10, further comprising: forming a third metal layer between the substrate and the first metal layer or a second surface of the substrate, the first surface system and the first surface The two surfaces are opposite. The method of claim 10, wherein the third metal layer is formed by an evaporation process. A light emitting device for generating infrared light includes: a substrate having a first surface; a first metal layer formed on the first surface of the substrate; and a dielectric layer ( a dielectric layer formed on the first metal layer, the dielectric layer having a thickness of less than 500 nanometers (nm); and a second metal layer formed on the dielectric layer; wherein the second metal layer There is at least one first hole. The illuminating device of claim 18, wherein when the illuminating device is heated, the dielectric layer has a surface plasma mode such that infrared light generated by the illuminating device is in the dielectric layer and The interface of the second metal layer and the interface of the second metal layer and the air are transferred.