TWI610453B - Photodiode and method for manufacturing photodiode - Google Patents

Description

Photodiode and method for manufacturing photodiode

The present invention relates to a photodiode and a method of fabricating the same, and more particularly to a photodiode for improving the degree of light sensing and a method of fabricating the same.

A photodiode is a semiconductor element that converts an optical signal into an electrical signal. Its core part is PN structure, which is different from the structure of general diode. In order to facilitate the acceptance of incident illumination, the area of PN structure is larger, the electrode area is smaller, and the junction of PN structure is very shallow. Less than 1 micron. Furthermore, the longer the wavelength of the light, the deeper the depth of the semiconductor layer that can be penetrated, but it is necessary to make the light wave penetrate the neutral region to make more electron holes combine to generate more current.

In general, optoelectronic semiconductors of germanium component materials are used in products with long wavelengths of infrared light and remote controls, while short wavelength light is not applied to optoelectronic semiconductors of germanium component materials. Furthermore, since the market economy is not efficient and the production is small, if short-wavelength light is to be applied to the optoelectronic semiconductor of the germanium component material to increase the photoelectric conversion efficiency, an additional mask must be fabricated to etch the photodiode. The structure is designed to enhance the depth of penetration of short-wavelength light (such as ultraviolet light).

At the current application level, it is illuminated by infrared rays. On the photodiode of the semiconductor layer material. However, for today's wearable devices, ultraviolet light (UV) is applied to the ultraviolet sensor (including the photodiode) of the wearable device. However, since the wavelength of the ultraviolet light is short and it is impossible to penetrate to the deeper semiconductor layer, the photoelectric conversion efficiency thereof is relatively low. Furthermore, if the depth of ultraviolet light penetration is to be enhanced, an additional mask must be fabricated to etch the structure of the photodiode, thereby increasing the manufacturing cost. Therefore, when a product for applying a wearable device is to be mass-produced, it is necessary to re-engineer the structure to absorb ultraviolet light and improve photoelectric conversion efficiency.

Accordingly, how to provide a method for manufacturing a photodiode has become an urgent research topic.

In view of the above problems, the present invention provides a method of fabricating a photodiode comprising the steps of: providing a substrate in step S01. In step S02, a first semiconductor layer is formed on one side of the substrate. In step S03, a second semiconductor layer is formed on the other side of the substrate. In step S04, etching is performed on the first semiconductor layer or the second semiconductor layer to a predetermined depth to form at least one photosensitive structure. In step S05, a protective layer is formed on at least one photosensitive structure. In step S06, an electrode structure is formed in the protective layer, wherein when the first semiconductor layer is a P-type semiconductor layer, the second semiconductor layer is an N-type semiconductor layer, or when the first semiconductor layer is an N-type semiconductor layer, The second semiconductor layer is a P-type semiconductor layer.

The invention provides a photodiode comprising a substrate and a first half a conductor layer, a second semiconductor layer, at least one photosensitive structure, a protective layer, and an electrode structure. The first semiconductor layer is disposed on one side of the substrate. The second semiconductor layer is disposed on the other side of the substrate. The at least one photosensitive structure is formed by etching the first semiconductor layer or etching the second semiconductor layer to a predetermined depth. The protective layer is disposed on at least one photosensitive structure. The electrode structure is disposed in the protective layer, wherein when the first semiconductor layer is a P-type semiconductor layer, the second semiconductor layer is an N-type semiconductor layer, or when the first semiconductor layer is an N-type semiconductor layer, the second semiconductor layer is P Type semiconductor layer.

As described above, the present invention forms at least one photosensitive structure by a process of etching on the structure of the light receiving region (P-type semiconductor layer or N-type semiconductor layer) to improve, for example, short-wavelength UV irradiation to the photodiode. The amount of absorption, that is, the degree of induction of UV, further increases the number of electron hole pairs combined to increase the current generated by the photodiode. Therefore, with the photodiode of the present invention and the method of manufacturing the same, the photodiode can be mass-produced in a cost-saving manner (with no additional cost of the photomask), and applied to various portable motion devices using UV light sensing. In order to enhance product value and market competitiveness.

S01~S06‧‧‧Steps

1‧‧‧Photoelectric diode

10‧‧‧Substrate

11‧‧‧First semiconductor layer

12‧‧‧Second semiconductor layer

13‧‧‧Photosensitive structure

14‧‧‧Protective layer

15, 16‧‧‧electrode structure

17‧‧‧Second semiconductor well

18‧‧‧First Semiconductor Well

1 is a flow chart of a method for fabricating a photodiode of the present invention; FIG. 2 is a top view of the photodiode of the present invention; and FIG. 3 is a cross-sectional view of the photodiode of the present invention; Is a top view of another embodiment of the photodiode of the present invention; 5 is a cross-sectional view of a photodiode of the present invention; FIG. 6 is a top view of a photodiode of a horizontal electrode structure of the present invention; and FIG. 7 is a photodiode of a horizontal electrode structure of the present invention. Schematic diagram of the polar body.

Please refer to FIG. 1 , which is a flow chart of a method for manufacturing a photodiode of the present invention. The flow of the photodiode manufacturing method includes: in step S01, providing a substrate. In step S02, a first semiconductor layer is formed on one side of the substrate. In step S03, a second semiconductor layer is formed on the other side of the substrate. In step S04, etching onto the first semiconductor layer or the second semiconductor layer to a predetermined depth to form at least one photosensitive structure. In step S05, a protective layer is formed on at least one photosensitive structure. In step S06, an electrode structure is formed in the protective layer.

As described above, the first semiconductor layer includes a P-type semiconductor layer or an N-type semiconductor layer, and the second semiconductor layer includes a P-type semiconductor layer or an N-type semiconductor layer, that is, when the first semiconductor is a P-type semiconductor layer, The second semiconductor is an N-type semiconductor layer, or when the first semiconductor is an N-type semiconductor layer, the second semiconductor is a P-type semiconductor layer. In other words, it is not limited in the present invention to etch at least one photosensitive structure on the P-type semiconductor layer or on the N-type semiconductor layer.

The protective layer includes a nitride layer or an oxide layer and has a protective function.

At least one photosensitive structure according to the first semiconductor layer or the second semiconductor The deep etching of the layer is formed to a predetermined depth to increase the degree of UV sensitivity. Therefore, when ultraviolet light is applied to the substrate, more combined pairs of electron holes can be generated to generate a larger current.

In the present invention, the electrode structure includes a horizontal type electrode structure or a vertical type electrode structure. The vertical type electrode structure includes a first electrode and a second electrode, and the first electrode is formed in the protective layer. The second electrode is formed on the first semiconductor layer or the second semiconductor layer. The polarities of the first electrode and the second electrode are correspondingly provided according to whether the first semiconductor layer and the second semiconductor layer are P-type semiconductor layers or N-type semiconductor layers. For example, when the first semiconductor layer is a P-type semiconductor layer, the electrode provided thereon is a positive electrode. The substrate includes an I-type semiconductor layer.

The horizontal electrode structure includes a first electrode and a second electrode formed in the protective layer. In addition, in the horizontal electrode structure, the first semiconductor layer or the second semiconductor layer forming the at least one photosensitive structure is a well structure, and at least one first semiconductor well or at least a second is formed on one side of the well structure. a semiconductor well, wherein a doping concentration of at least one first semiconductor well or at least one second semiconductor well is greater than a doping concentration of the substrate, and a doping concentration of the first semiconductor layer or the second semiconductor layer disposed on the other side of the substrate is also Greater than the doping concentration of the substrate.

Please refer to FIG. 2 and FIG. 3 together, which are a top view of the photodiode of the present invention and a cross-sectional view of the A-A line segment. The photodiode 1 includes a substrate 10, a first semiconductor layer 11, a second semiconductor layer 12, at least one photosensitive structure 13, a protective layer 14, and electrode structures 15, 16. The first semiconductor layer 11 is disposed on one side of the substrate 10. The second semiconductor layer 12 is disposed on the other side of the substrate 10. At least one sensitive The structure 13 is formed by etching the first semiconductor layer 11 or the second semiconductor layer 12 to a predetermined depth. The protective layer 14 is disposed on at least one of the photosensitive structures 13. The electrode structures 15, 16 are disposed in the protective layer 14.

As described above, the first semiconductor layer 11 includes a P-type semiconductor layer or an N-type semiconductor layer, and the second semiconductor layer 12 includes a P-type semiconductor layer or an N-type semiconductor layer, that is, when the first semiconductor layer 11 is a P-type semiconductor In the case of the layer, the second semiconductor layer 12 is an N-type semiconductor layer, or when the first semiconductor layer 11 is an N-type semiconductor layer, the second semiconductor layer 12 is a P-type semiconductor layer. In other words, it is not limited in the present invention to form at least one photosensitive structure 13 on the P-type semiconductor layer or on the N-type semiconductor layer. In addition, the protective layer 14 includes a nitride layer or an oxide layer.

At least one photosensitive structure 13 is formed by etching to a predetermined depth according to the depth of the first semiconductor layer 11 or the second semiconductor layer 12 to increase the degree of UV sensitivity. Therefore, when ultraviolet light is applied to the substrate 10, more combined pairs of electron holes can be generated to generate a larger current.

In the present invention, the electrode structures 15, 16 include a horizontal electrode structure or a vertical electrode structure. Figure 3 is a photodiode of a vertical electrode structure. The vertical type electrode structure includes a first electrode and a second electrode, and the first electrode is formed in the protective layer 14. The second electrode is formed on the first semiconductor layer 11 or the second semiconductor layer 12. The polarities of the first electrode and the second electrode are correspondingly provided according to whether the first semiconductor layer 11 and the second semiconductor layer 12 are P-type semiconductor layers or N-type semiconductor layers. For example, when the first semiconductor layer 11 is a P-type semiconductor layer, the electrode provided thereon is a positive electrode. The substrate 10 includes an I-type semiconductor layer. In addition, the first electrode and The positive and negative polarities of the second electrode correspond to the first semiconductor layer 11 and the second semiconductor layer 12 that are in contact. In the vertical electrode structure, the first semiconductor layer 11 or the second semiconductor layer 12 forming the at least one photosensitive structure 13 is a well structure, and at least one first semiconductor well or at least one is formed on one side of the well structure. In the second semiconductor well, in the embodiment of Fig. 3, a well structure is formed in the second semiconductor layer 12, and the first semiconductor well 18 is formed on both sides of the well structure. The doping concentration of the at least one first semiconductor well 18 or the at least one second semiconductor well is greater than the doping concentration of the substrate 10, and the doping concentration of the first semiconductor layer 11 or the second semiconductor layer 12 disposed on the other side of the substrate 10 It is also larger than the doping concentration of the substrate 10, and in the illustration of FIG. 3, the first semiconductor layer 11 is disposed on the other side of the substrate 10.

Please refer to FIG. 4 and FIG. 5 together, which are a top view of another embodiment of the photodiode of the present invention and a cross-sectional view of the line B-B. The difference from the above embodiment is that the photosensitive structure 13 of this embodiment is a single structure, and the photosensitive structure 13 of the above embodiment is at least one photosensitive structure 13, but whether it is a single structure or at least one photosensitive Structure 13, which increases the degree of UV sensitivity. Further, the first electrode and the second electrode have positive and negative polarities corresponding to the first semiconductor layer 11 and the second semiconductor layer 12 that are in contact. In the vertical electrode structure, the first semiconductor layer 11 or the second semiconductor layer 12 forming the at least one photosensitive structure 13 is a well structure, and at least one first semiconductor well or at least one is formed on one side of the well structure. In the second semiconductor well, in the embodiment of Fig. 5, a well structure is formed in the second semiconductor layer 12, and the first semiconductor well 18 is formed on both sides of the well structure. Doping concentration of at least one first semiconductor well 18 or at least one second semiconductor well The doping concentration of the first semiconductor layer 11 or the second semiconductor layer 12 disposed on the other side of the substrate 10 is also greater than the doping concentration of the substrate 10, which is shown in the diagram of FIG. The first semiconductor layer 11 is disposed on the other side of the substrate 10 as an example.

Please refer to FIG. 6 and FIG. 7 , which are a top view of the photodiode of the horizontal electrode structure of the present invention and a schematic cross-sectional view of the B-B line segment. The horizontal electrode structure includes a first electrode and a second electrode, which are formed in the protective layer 14, and the positive and negative polarities correspond to the first semiconductor layer 11 and the second semiconductor layer 12 that are in contact. In addition, in the horizontal electrode structure, the first semiconductor layer 11 or the second semiconductor layer 12 forming the at least one photosensitive structure 13 is a well structure, and at least one first semiconductor well or at least one side is formed on one side of the well structure. A second semiconductor well, in the embodiment of FIG. 7, forms a well structure in the first semiconductor layer 11 and forms a second semiconductor well 17 on both sides of the well structure. The doping concentration of the at least one first semiconductor well or the at least one second semiconductor well 17 is greater than the doping concentration of the substrate 10, and the doping concentration of the first semiconductor layer 11 or the second semiconductor layer 12 disposed on the other side of the substrate 10 It is also larger than the doping concentration of the substrate 10, and the second semiconductor layer 12 is disposed on the other side of the substrate 10 in the illustration of FIG.

In summary, the present invention forms at least one photosensitive structure by etching in the structure of the light receiving region (P-type semiconductor layer or N-type semiconductor layer) to improve, for example, short-wavelength UV irradiation to the photodiode. The amount of absorption, that is, the degree of induction of UV, further increases the number of electron hole pairs combined to increase the current generated by the photodiode. Therefore, by the photoelectric of the present invention The diode and its manufacturing method can save a large amount of photodiode in a cost-saving manner (with no additional cost of the mask), and can be applied to various portable sports devices using UV light sensing, thereby enhancing product value. And market competitiveness.

S01~S06‧‧‧Steps

Claims (18)

A method of manufacturing a photodiode includes: providing a substrate; forming a first semiconductor layer on one side of the substrate; forming a second semiconductor layer on the other side of the substrate; etching the portion of the first semiconductor layer or The second semiconductor layer is formed to form at least one photosensitive structure; a protective layer is formed on the at least one photosensitive structure; and an electrode structure is formed in the protective layer. The method of manufacturing a photodiode according to claim 1, wherein the first semiconductor comprises a P-type semiconductor layer, and the second semiconductor comprises an N-type semiconductor layer. The method of manufacturing a photodiode according to claim 1, wherein the first semiconductor comprises an N-type semiconductor layer, and the second semiconductor comprises a P-type semiconductor layer. The method of manufacturing a photodiode according to claim 1, wherein the protective layer comprises a nitride layer or an oxide layer. The method of manufacturing a photodiode according to claim 1, wherein the electrode structure comprises: a first electrode formed in the protective layer; and a second electrode formed on the first semiconductor layer or On the second semiconductor layer. The method of manufacturing a photodiode according to claim 5, wherein the substrate comprises an I-type semiconductor layer. The method of manufacturing a photodiode according to claim 1, wherein the electrode structure comprises a first electrode and a second electrode, and is formed in the protection In the protective layer. The method of manufacturing a photodiode according to claim 7, wherein the first semiconductor layer or the second semiconductor layer forming the at least one photosensitive structure is a well structure. The method for fabricating a photodiode according to claim 8 , further comprising forming at least one first semiconductor well or at least one second semiconductor well on one side of the well structure, wherein the at least one first semiconductor well Or the doping concentration of the at least one second semiconductor well is greater than the doping concentration of the substrate. A photodiode comprising: a substrate; a first semiconductor layer disposed on one side of the substrate; a second semiconductor layer disposed on the other side of the substrate; at least one photosensitive structure, the etched portion a semiconductor layer or the second semiconductor layer is formed; a protective layer is disposed on the at least one photosensitive structure; and an electrode structure is disposed in the protective layer. The photodiode of claim 10, wherein the first semiconductor comprises a P-type semiconductor layer, and the second semiconductor comprises an N-type semiconductor layer. The photodiode of claim 10, wherein the first semiconductor comprises an N-type semiconductor layer, and the second semiconductor comprises a P-type semiconductor layer. The photodiode of claim 10, wherein the protective layer comprises a nitride layer or an oxide layer. The photodiode of claim 10, wherein the electrode structure comprises: a first electrode formed in the protective layer; and a second electrode formed on the first semiconductor layer or the second On the semiconductor layer. The photodiode of claim 14, wherein the substrate comprises an I-type semiconductor layer. The photodiode of claim 10, wherein the electrode structure comprises a first electrode and a second electrode formed in the protective layer. The photodiode of claim 16, wherein the first semiconductor layer or the second semiconductor layer forming the at least one photosensitive structure is a well structure. The photodiode of claim 17, further comprising at least one first semiconductor well or at least one second semiconductor well formed on one side of the well structure, wherein the at least one first semiconductor well or the The doping concentration of the at least one second semiconductor well is greater than the doping concentration of the substrate.