TWM573516U - Photo diode - Google Patents

Abstract

A light-detecting diode includes: a substrate having a side surface of the substrate having a beveled light incident surface; and an epitaxial layer disposed above the substrate. Thereby, the photodetecting diode of the present invention has excellent responsiveness when coupled to the side.

Description

Light detector diode

This creation is about a light-detecting diode, especially a light-detecting diode that increases the responsiveness of the side light.

Photodiode (Photodiode) is a semiconductor component that converts optical signals into electrical signals. Common applications include solar cells and charge-coupled devices (CCDs). Common light-detecting diodes are available in PN type, PIN type, and Avalanche type.

Taking the PN type photodetector as an example, the working principle is to apply a reverse bias voltage and a built-in electric field to a PN junction. When the light is irradiated on the vacant region of the PN junction, the energy in the photon can be A bound electron is given to overcome the energy gap, jumping from the valence band to the conduction band. After the electron enters the conduction band, a hole is formed in the valence band to form a pair of electron hole pairs. The electron hole is driven by the electric field to generate photocurrent, and the voltage can be outputted on the external circuit and the load to complete the optical signal conversion. The process of becoming a signal.

However, conventional light-detecting diodes are mostly front-coupled and back-coupled, and although some of the light-detecting diodes can be coupled from the side, there is still a small light-receiving area. The disadvantage of insufficient responsivity, so when used as a light sensor, the light from the side is not effectively converted.

Therefore, it is necessary to propose a creation to improve the above problems.

The technical means for solving the problems of the prior art is to provide a light-detecting diode, comprising: a substrate, the side of the substrate is a slanted entrance surface; and an epitaxial layer is disposed on Above the substrate.

In an embodiment of the present invention, the angle between the light incident surface and the normal of the substrate is 25 degrees to 75 degrees.

In an embodiment of the present invention, the angle between the light incident surface and the normal of the substrate is 30 degrees to 60 degrees.

In an embodiment of the inventive photodetecting diode, the angle between the light incident surface and the normal of the substrate is 45 degrees.

In an embodiment of the photodetecting diode of the present invention, an etch stop layer is further disposed between the substrate and the epitaxial layer.

In an embodiment of the photodetecting diode of the present invention, an anti-reflective layer is further disposed above the epitaxial layer, and the anti-reflective layer is a metal alloy.

In an embodiment of the inventive photodetector diode, wherein the metal alloy comprises Ti, Pt, Au, and AuGeNi.

Through the technical means of the creation, a light-detecting diode is proposed, which uses a light-incident surface formed on the side of the substrate to make the light-detecting diode It also has a very high responsiveness when coupled from the side, and has a wider range of applications.

100‧‧‧Detecting diode

1‧‧‧Substrate

11‧‧‧Into the glossy surface

2‧‧‧ epitaxial layer

3‧‧‧etch stop layer

41‧‧‧Electrode

42‧‧‧Electrode

5‧‧‧Anti-reflective layer

6‧‧‧ Passivation layer

A1~A3‧‧‧ steps

B1~B4‧‧‧Steps

Θ‧‧‧ angle

L‧‧‧Light

Figure 1A is a schematic diagram of one embodiment of the photodetector diode of the present invention.

Fig. 1B is a schematic view showing another embodiment of the photodetecting diode of the present invention.

Figure 2A is a schematic diagram of the side coupling light of the photodetector diode of the present invention.

Fig. 2B is a schematic view showing the side coupling of the light-detecting diode of the light-incident surface of another created oblique mode.

The third figure is a manufacturing flow chart of one of the photodetecting diodes of the present invention.

Figure 4 is another manufacturing flow chart of the photodetector diode of the present invention.

Embodiments of the present creation will be described below based on FIGS. 1A to 4 . The drawings and the description are only for the purpose of assisting the understanding of the present invention, and are one of the embodiments of the present invention, and are not intended to limit the implementation of the present invention.

Referring to FIG. 1A, a light-detecting diode 100 is disclosed, which includes a substrate 1 and an epitaxial layer 2.

The material of the substrate 1 may be a compound semiconductor such as InP or GaAs.

The epitaxial layer 2 is disposed above the substrate 1 and includes a P-type semiconductor layer and an N-type semiconductor layer. The material of the epitaxial layer 2 may be AlGaAs, AlAs, InGaAs or GaAsP. In one embodiment, the P-type semiconductor layer is expanded A bulk process is formed in the N-type semiconductor layer.

The side surface of the substrate 1 has a light incident surface 11 having a slope. As shown in FIGS. 1A and 1B, the angle θ between the light incident surface 11 and the normal line of the substrate 1 is 25 degrees to 75 degrees. Preferably, the angle θ between the light incident surface 11 and the normal line of the substrate 1 is 30 degrees to 60 degrees.

The beveled light incident surface 11 allows the photodetector diode 100 to have excellent responsivity in the case where the side light is coupled (as shown in FIG. 2A). The responsiveness of a light-detecting diode is defined as the current that can be generated by inputting light energy per unit of power, in A/W. In a conventional conventional light detecting diode, the substrate is not changed in any angle, that is, when the light incident surface is parallel to the substrate normal line by 0 degrees, the responsivity is 0.01 A/W, and the photodetecting diode 100 of the present invention, As shown in FIG. 2A, the light incident surface 11 having a slope is formed. After the light beam L is incident on the light incident surface 11, a light absorbing layer which is refracted and internally reflected and reaches the epitaxial layer 2 is generated to generate a photocurrent. Further, when the angle θ is 60 degrees, the responsivity can reach 0.5 A/W or more; and when the angle θ is 45 degrees, the responsivity can reach 0.65 A/W or more.

It should be noted that the incident surface 11 of the inclined surface can be inclined in two directions, with the direction of the substrate 1 pointing to the epitaxial layer 2 as a reference, and the incident surface 11 of the inclined surface can be tilted to the left (eg, Figure 2A), or tilt to the right (as shown in Figure 2B). For convenience of representation, the present specification indicates the angle between the incident surface 11 of the inclined surface and the normal line of the substrate 1 at an angle θ. The position of the angle θ of the two different tilting modes is as shown in the figure.

When the light incident surface 11 is inclined to the left as shown in FIG. 2A In the formula, the light L incident from the left is refracted and then falls at the position of the middle and the rear (near the light source). When the light incident surface 11 is in the form of being inclined to the right as shown in FIG. 2B, the light L incident from the left is refracted and then falls at the position of the middle and the front (away from the light source). The terms of the position, the oblique direction, and the position of the light source mentioned in the present specification are relative positions of the drawings, and are not limited to this term.

The light incident surface 11 of the substrate 1 can be formed by machining. In one embodiment, the light incident surface 11 is cut in the substrate 1 with a diamond knife. The advantage of using mechanical processing is that it is easy to form a desired angle, the stability is high, there is no problem of uniformity, and the appearance is flat and the defects are not easy to be defective, and the film is peeled off.

Alternatively, the light incident surface 11 of the substrate 1 can also be formed by etching a chemical. When the light-incident surface 11 is selected to be etched by a chemical, preferably, as shown in FIG. 1B, the light-detecting diode 100 further includes an etch stop layer 3, and the etch stop layer 3 is formed on the substrate. 1 and between the epitaxial layers 2. The etch stop layer 3 has a protective effect to avoid the unevenness of the etching process and to destroy the structure of the epitaxial layer 2. In some embodiments, the material of the etch stop layer 3 is InGaAs, InGaP or InGaAsP.

The epitaxial layer 2 and the etch stop layer 3 may be formed by metal organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), or a combination of the above.

In some embodiments, the agent used for etching the substrate 1 may be HCl, HBr, HNO ₃ , H ₃ PO ₄ , NH ₄ OH, H ₂ O ₂ , H ₂ SO _{4 ,} etc., and different materials according to the substrate 1 Properties (such as lattice orientation) are selected by etching different substrates. For example, when an InP material is used as the substrate 1, etching with a ratio of 1:3 HCl and H ₃ PO ₄ may be used; when a GaAs material is used as the substrate 1, an NH ratio of 1:1:1 may be used. The substrate 1 is etched with ₄ OH, H ₂ O ₂ and H ₂ O.

Optionally, the light incident surface 11 of the substrate 1 can also be sequentially processed and etched, and the P-type semiconductor layer of the epitaxial layer 2 is first machined to a predetermined depth before the light incident surface 11 is formed. The agent is then added to etch to form the light incident surface 11, which has the advantage that the etch stop layer 3 does not have to be formed and the time required for etching can be saved.

As shown in FIGS. 1A and 1B, the photodetecting diode 100 of the present invention is further provided with electrodes 41 and 42 for connecting an external circuit to output a voltage generated by light. In one embodiment, the photodetecting diode 100 of the present invention comprises an anti-reflective layer 5 disposed on the epitaxial layer 2, for example, on the P-type semiconductor layer of the epitaxial layer 2, the anti-reflection The layer 5 acts to reduce the light that has entered the semiconductor to be reflected again, allowing the light to be efficiently converted in the light absorbing layer in the epitaxial layer 2, increasing the responsiveness. The antireflection layer of the conventional photodetector diode is usually composed of an oxide such as SiO2 or SiNx, and the antireflection layer 5 in the photodetector diode 100 of the present invention is a metal alloy. In one embodiment, the metal The alloys include Ti, Pt, Au, and AuGeNi, which enable secondary absorption of light, making the inventive photodetector diode 100 more responsive than conventional photodetectors.

As shown in Figures 1A and 1B, the photodetector diode of the present invention 100 includes a passivation layer 6 disposed on a portion of the surface of the epitaxial layer 2, the portion of the surface including other surfaces not connected to the anti-reflective layer 5, and the electrode 41 is disposed on the passivation layer 6 and partially connected to the surface Epitaxial layer 2.

Furthermore, the manufacturing process of the photodetecting diode of the present invention can be referred to the process shown in FIG. 3 and please refer to FIG. 1A at the same time. The manufacturing process of the photodetecting diode includes: Step A1: providing a substrate 1 Step A2: forming an epitaxial layer 2 on the substrate 1; and step A3: forming a beveled incident surface 11 on the side of the substrate 1.

The material and molding method of the substrate 1 and the epitaxial layer 2 have been described in the foregoing, and therefore will not be described again.

The forming manner of the light-incident surface 11 in the step A3 can be formed by machining. As described above, in one embodiment of the present invention, the light-incident surface 11 is cut on the side of the substrate 1 by a diamond knife. In one embodiment, the angle between the light incident surface 11 and the normal of the substrate 1 is 25 degrees to 75 degrees. Preferably, the angle between the light incident surface 11 and the normal line of the substrate 1 is 30 degrees to 60 degrees. As described above, when the angle θ is 60 degrees, the responsivity can reach 0.5 A/W or more; and when the angle θ is 45 degrees, the responsivity can reach 0.65 A/W or more.

As described above, the manufacturing process of the photodetecting diode of the present invention further includes forming an anti-reflective layer 5 on the epitaxial layer 2, and the anti-reflective layer 5 is a metal alloy. In one embodiment, the metal alloy includes Ti, Pt, Au, and AuGeNi.

In addition, the manufacturing of the photodetector diode can also use another manufacturing process, please refer to the process shown in Figure 4 and please also refer to Figure 1B, The manufacturing process of the photodetecting diode includes: step B1: providing a substrate 1; step B2: forming an etch stop layer 3 on the substrate 1; step B3: forming an epitaxial layer 2 on the etch stop layer 3; And step B4: etching the side of the substrate 1 with a chemical to form a beveled light incident surface 11.

The materials and molding methods of the substrate 1, the epitaxial layer 2, and the etch stop layer 3 have been described above, and therefore will not be described herein.

The agent used for etching the light-incident surface 11 in step B4 is as described above and will not be described separately. In one embodiment, the angle between the light incident surface 11 and the normal of the substrate 1 is 25 degrees to 75 degrees. Preferably, the angle between the light incident surface 11 and the normal line of the substrate 1 is 30 degrees to 60 degrees. As described above, when the angle θ is 60 degrees, the responsivity can reach 0.5 A/W or more; and when the angle θ is 45 degrees, the responsivity can reach 0.65 A/W or more.

As described above, the manufacturing process of the photodetecting diode of the present invention further includes forming an anti-reflective layer 5 on the epitaxial layer 2, and the anti-reflective layer 5 is a metal alloy. In one embodiment, the metal alloy includes Ti, Pt, Au, and AuGeNi.

In addition, in the above two manufacturing processes, a passivation layer 6 is formed on the epitaxial layer 2, and a portion of the passivation layer 6 is etched to expose the epitaxial layer 2. In an embodiment, the Lei is exposed. a P-type semiconductor layer region of the crystal layer 2, and the anti-reflective layer 5 and the electrode 41 are respectively formed on the P-type semiconductor layer of the epitaxial layer 2, wherein the electrode 41 partially extends onto the passivation layer 6. .

In combination with the above embodiments, the light-detecting diode and the method of manufacturing the same according to the present invention use a light-incident surface formed on a side surface of the substrate to be inclined The light-detecting diode has a very high responsivity when coupled from the side, and the application method is more extensive.

The above description is only a preferred and feasible embodiment of the present invention, and thus does not limit the scope of the patents of the present invention. The equivalent structural changes that are made by using the present specification and the contents of the drawings are all included in the scope of the present creation. , combined with Chen Ming.

Claims (7)

A light-detecting diode includes: a substrate having a side surface of the substrate having a beveled light incident surface; and an epitaxial layer disposed above the substrate. The photodetecting diode according to claim 1, wherein the incident surface is at an angle of 25 to 75 degrees from a normal line of the substrate. The photodetecting diode according to claim 2, wherein the incident surface is at an angle of 30 to 60 degrees with respect to a normal line of the substrate. The photodetecting diode according to claim 3, wherein an angle between the light incident surface and a normal line of the substrate is 45 degrees. The photodetecting diode according to any one of claims 1 to 4, further comprising an etch stop layer disposed between the substrate and the epitaxial layer. The light-detecting diode according to any one of claims 1 to 4, further comprising an anti-reflection layer disposed above the epitaxial layer, wherein the anti-reflection layer is a metal alloy. The photodetector of claim 6, wherein the metal alloy comprises Ti, Pt, Au, and AuGeNi.