A germanium photodetector device and semiconductor apparatus

Abstract

This invention discloses a germanium photodetector and semiconductor device. The germanium photodetector includes: a silicon substrate; a first germanium thin film layer deposited on the silicon substrate; the first germanium thin film layer having multiple penetrating dislocations extending through its thickness; multiple pits corresponding one-to-one with the multiple penetrating dislocations formed on the surface of the first germanium thin film layer, and the inner surface of each pit being covered with an amorphous material layer; and a second germanium thin film layer deposited on the surface of the first germanium thin film layer and on the amorphous material layer within each pit, filling each pit. The amorphous material layer effectively blocks the extension of dislocations, reduces dislocation density, and ensures the photoelectric conversion efficiency of the device. Furthermore, by integrating the epitaxial chamber, deposition chamber, and pre-cleaning chamber into the same semiconductor device through a transfer chamber to produce the germanium photodetector, the contact path of external contaminants is reduced, the process flow is simplified, production efficiency is improved, and space and cost are optimized.

Description

Technical Field

[0001] This utility model relates to the field of germanium photodetector technology, and in particular to a germanium photodetector and semiconductor device. Background Technology

[0002] In the epitaxial growth technology of semiconductor materials, lattice matching is one of the key factors determining the quality of heteroepitaxial films. Taking silicon and germanium, two important semiconductor materials, as examples, silicon has a lattice constant of 0.543 nm and germanium has a lattice constant of 0.566 nm, with a lattice mismatch rate of approximately 4.2% between them.

[0003] When germanium atoms begin to deposit on the surface of a silicon substrate, the initial atomic layers tend to conform to the silicon lattice structure due to interfacial bonding forces. This results in significant compressive strain within the germanium film (germanium atoms are forced to contract to fit the smaller silicon lattice). However, as the film thickness increases, the accumulated strain energy gradually exceeds the elastic limit of the material. At this point, the lattice structure releases the excess energy by introducing dislocations. Once formed, dislocations readily extend from the interface between the germanium film and the substrate into the interior of the germanium film, eventually forming penetrating dislocations that run through the entire germanium film.

[0004] For germanium photodetectors, the presence of through-dislocations can severely impair their photoelectric performance. On the one hand, through-dislocations, as defects in the crystal structure, become recombination centers for charge carriers, significantly reducing carrier mobility and lifetime, leading to slower response speed and decreased quantum efficiency. On the other hand, dense through-dislocations scatter photons, affecting the light transmission path in the thin film and weakening light absorption efficiency. Furthermore, the presence of through-dislocations reduces the stability and reliability of the device, making it more prone to performance degradation or even failure during long-term operation.

[0005] The statements herein provide only background information relating to this invention and do not necessarily constitute prior art. Utility Model Content

[0006] The purpose of this invention is to provide a germanium photodetector with improved structure. The surface of the first germanium thin film layer of the device has a pit formed at the position of the penetrating dislocation. The pit is covered only by an amorphous material layer. The amorphous material layer can effectively block the extension of dislocations and reduce the dislocation density, thus ensuring the photoelectric conversion efficiency of the device and facilitating the high-quality and high-efficiency growth of the second germanium thin film layer.

[0007] To achieve the above objectives, this utility model provides a germanium photodetector device, comprising:

[0008] silicon substrate;

[0009] A first germanium thin film layer is deposited on the silicon substrate; the first germanium thin film layer has a plurality of penetrating dislocations that extend through its thickness; a plurality of pits corresponding one-to-one with the plurality of penetrating dislocations are formed on the surface of the first germanium thin film layer, and the inner surface of each pit is covered with an amorphous material layer.

[0010] A second germanium thin film layer is deposited on the surface of the first germanium thin film layer and on the amorphous material layer within each of the pits, and fills each of the pits.

[0011] Optionally, the depth of the pit is greater than the thickness of the amorphous material layer.

[0012] Optionally, the depth of the pit is 18nm-22nm, and the thickness of the amorphous material layer is 8nm-12nm.

[0013] Optionally, the opening width of the pit on the surface of the first germanium thin film layer is 1μm-2μm.

[0014] Optionally, the thickness of the first germanium thin film layer is 30nm-90nm, and the depth of the pit is less than the thickness of the first germanium thin film layer.

[0015] Optionally, the thickness of the second germanium thin film layer is 470nm-1410nm.

[0016] Optionally, the pit is V-shaped.

[0017] Optionally, the constituent material of the amorphous material layer is any one of SiO2, Si3N4, and SiON.

[0018] This utility model also provides a semiconductor device for manufacturing the above-mentioned germanium photodetector device, the semiconductor device comprising:

[0019] An epitaxial chamber is used to deposit a first germanium thin film layer on the surface of a silicon substrate, form a pit at the position corresponding to the penetrating dislocation on the surface of the first germanium thin film layer, and deposit a second germanium thin film layer on the surface of the first germanium thin film layer and on an amorphous material layer in the pit.

[0020] A deposition chamber for depositing an amorphous material layer on the surface of the first germanium thin film layer and within the pit;

[0021] A pre-cleaning chamber is used to etch the amorphous material layer on the surface of the first germanium thin film layer;

[0022] The transfer chamber is connected to the epitaxial chamber, the deposition chamber, and the pre-cleaning chamber, respectively.

[0023] The transfer chamber is equipped with a transfer device for transferring wafers between the epitaxial chamber, the deposition chamber, and the pre-cleaning chamber.

[0024] Optionally, the epitaxial chamber is provided with a gas input device, which is used to input chlorine-containing corrosive gas or fluorine-containing corrosive gas into the epitaxial chamber to form the pit, and is also used to input germane gas into the epitaxial chamber to form the first germanium thin film layer and the second germanium thin film layer.

[0025] Compared with the prior art, the technical solution of this utility model has at least the following beneficial effects:

[0026] 1) In the germanium photodetector of this invention, a pit is formed on the surface of the first germanium thin film corresponding to the position of the penetrating dislocation, and an amorphous material layer is disposed on the inner surface of the pit. On the one hand, since the random atomic arrangement of the amorphous material layer cannot provide the periodic path required for dislocation slip, dislocation slip is hindered. Moreover, the amorphous material layer will generate compressive stress on the first germanium thin film layer during the subsequent cooling process, inhibiting dislocation slip, thereby effectively blocking the extension of dislocations and reducing dislocation density. At the same time, the amorphous material layer only covers the inner surface of the pit and does not fill the pit completely, ensuring the photoelectric conversion efficiency of the device. On the other hand, within the temperature range of 350℃-400℃, the surface of the first germanium thin film layer is flat, which can avoid island defects and release most of the elastic strain.

[0027] 2) This utility model integrates the epitaxial chamber, deposition chamber and pre-cleaning chamber into the same semiconductor equipment through the transfer chamber to produce germanium photodetector devices, reducing the contact path of external contaminants, simplifying the process flow, improving production efficiency, and helping to optimize space and cost. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the germanium photodetector device of this utility model.

[0029] Figure 2 A schematic diagram of the structure of the present invention showing the formation of a first germanium thin film layer on the surface of a silicon substrate.

[0030] Figure 3 This is a schematic diagram of the recess of this utility model.

[0031] Figure 4 This is a schematic diagram of the amorphous material layer inside the pit of this utility model.

[0032] Figure 5 This is a schematic diagram of the surface of the first germanium thin film layer and the amorphous material layer in the pit of this utility model.

[0033] Figure 6 This is a schematic diagram of the structure of the semiconductor device of this utility model.

[0034] Figure 7 This is a process flow diagram for manufacturing germanium photodetector devices according to this utility model.

[0035] Attached image labels:

[0036] Silicon substrate 10, first germanium thin film layer 20, through dislocation 21, pit 30, amorphous material layer 40, second germanium thin film layer 50, epitaxial chamber 100, first valve 110, deposition chamber 200, second valve 210, pre-cleaning chamber 300, third valve 310, transfer chamber 400, front-end module 500, fourth valve 510, loading area 600. Detailed Implementation

[0037] The germanium photodetector and semiconductor device proposed in this utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this utility model will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, only for the purpose of conveniently and clearly illustrating the embodiments of this utility model. Please refer to the drawings to make the purpose, features, and advantages of this utility model more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0038] In existing technologies, penetrating dislocations that penetrate germanium thin films severely impair the photoelectric performance of germanium photodetectors. To address this issue, this invention improves the structure of the germanium photodetector by forming pits on the surface of the first germanium thin film corresponding to the locations of penetrating dislocations, and depositing an amorphous material layer on the inner surface of these pits. The amorphous material layer suppresses dislocation slip, effectively blocking dislocation propagation and reducing dislocation density. Simultaneously, the amorphous material layer does not completely fill the pits, reducing its blocking effect on incident light and thus minimizing optical losses in the light absorption region. This structural design of the present invention, while suppressing dislocation propagation, ensures effective coverage of the light absorption region by the incident light flux, providing the necessary conditions for maintaining the photoelectric conversion efficiency of the device.

[0039] like Figure 1 As shown, the germanium photodetector device provided by this utility model includes: a silicon substrate 10, a first germanium thin film layer 20, a penetrating dislocation 21, a pit 30, an amorphous material layer 40, and a second germanium thin film layer 50.

[0040] The first germanium thin film layer 20 is deposited on the silicon substrate 10. Due to the influence of compressive strain, the first germanium thin film layer 20 has multiple penetrating dislocations 21 that extend through its thickness (see...). Figure 2 The surface of the first germanium thin film layer 20 has a plurality of pits 30 corresponding one-to-one with the plurality of through-dislocations 21 (see...). Figure 3 Each of the recesses 30 has an inner surface covered with an amorphous material layer 40 (see...). Figure 4 The second germanium thin film layer 50 is deposited on the surface of the first germanium thin film layer 20 and on the amorphous material layer 40 in each of the pits 30, and fills each of the pits 30.

[0041] In some embodiments, the depth of the pit 30 is greater than the thickness of the amorphous material layer 40. For example, the depth of the pit 30 is 18nm-22nm, and the thickness of the amorphous material layer 40 is 8nm-12nm. The amorphous material layer 40 is composed of any one of SiO2, Si3N4, or SiON. Because the random atomic arrangement of the amorphous material layer 40 cannot provide the periodic path required for dislocation slip, dislocation slip is hindered. Furthermore, the amorphous material layer 40 generates compressive stress on the first germanium thin film layer 20 during subsequent cooling, suppressing dislocation slip and effectively blocking dislocation propagation and reducing dislocation density. Simultaneously, the thickness of the amorphous material layer 40 is less than the depth of the pit 30, covering only the inner surface of the pit 30 and not filling it completely, minimizing shading of the light absorption region and ensuring the photoelectric conversion efficiency of the device.

[0042] In this embodiment, the pit 30 is V-shaped, and the opening width of the pit 30 on the surface of the first germanium thin film layer 20 is 1μm-2μm, which is beneficial to better deposit the amorphous material layer 40 into the pit 30.

[0043] In some embodiments, the depth of the pit 30 is less than the thickness of the first germanium thin film layer 20, which ensures that dislocation slip is suppressed without severely damaging the structure of the first germanium thin film layer 20. The thickness of the first germanium thin film layer 20 is 30nm-90nm, and the thickness of the second germanium thin film layer 50 is 470nm-1410nm, so that the total thickness of the germanium thin film layers in the germanium photodetector is kept between 500nm-1500nm.

[0044] This utility model also provides a semiconductor device, which is used for manufacturing... Figure 1 The germanium photodetector device shown, such as Figure 6As shown, the semiconductor device includes: an epitaxial chamber 100, a deposition chamber 200, a pre-cleaning chamber 300, a transfer chamber 400, a front-end module 500, and a loading area 600. The transfer chamber 400 is connected to the epitaxial chamber 100, the deposition chamber 200, the pre-cleaning chamber 300, and the front-end module 500. The transfer chamber 400 is equipped with a transfer device for transferring wafers between the epitaxial chamber 100, the deposition chamber 200, and the pre-cleaning chamber 300. The specific connection method between the transfer chamber 400 and each chamber is as follows: the transfer chamber 400 is connected to the epitaxial chamber 100 through a first valve 110, to the deposition chamber 200 through a second valve 210, to the pre-cleaning chamber 300 through a third valve 310, and to the front-end module 500 through a fourth valve 510. The front-end module 500 is connected to the loading area 600 through a fifth valve (not shown in the figure). The loading area 600 is used to place wafer loading cassettes.

[0045] The epitaxial chamber 100 is used to deposit a first germanium thin film layer 20 on the surface of the silicon substrate 10, form a pit 30 on the surface of the first germanium thin film layer 20 at a position corresponding to the penetrating dislocation 21, and deposit a second germanium thin film layer 50 on the surface of the first germanium thin film layer 20 and on the amorphous material layer 40 in the pit 30.

[0046] The deposition of the aforementioned germanium thin film and the formation of the pits both require the input of gas. Therefore, the epitaxial chamber 100 is equipped with a gas input device, which has the following two functions:

[0047] On one hand, a chlorine-containing corrosive gas (such as HCl) or a fluorine-containing corrosive gas (such as HF) is introduced into the epitaxial chamber 100 to etch through-dislocations 21 in the first germanium thin film layer 20, forming pits 30 on its surface. At the positions on the surface of the first germanium thin film layer 20 corresponding to the through-dislocations 21, the atomic bonds are incomplete, resulting in higher energy. The corrosive gas preferentially dissolves atoms at these locations, forming pits. Due to the anisotropic corrosion characteristics of crystals (the different atomic arrangements and bonding strengths on different crystal planes lead to different corrosion rates), the dissolution rate of the corrosive gas varies for different crystal orientations, resulting in pits with fixed geometric shapes (such as the V-shape in this example).

[0048] On the other hand, germane gas is introduced into the epitaxial chamber 100 to form a first germanium thin film layer 20 and a second germanium thin film layer 50. In this embodiment, the temperature inside the epitaxial chamber 100 is controlled at 350°C-400°C and the pressure is controlled at 50 torr-200 torr. Germane gas with a flow rate of 20 sccm / min-50 sccm / min is introduced into the epitaxial chamber 100 through a gas input device to form the first germanium thin film layer 20. The growth rate of the first germanium thin film layer 20 is 5 nm / min-15 nm / min. The temperature inside the epitaxial chamber 100 is controlled at 550°C-600°C and the pressure is controlled at 150 torr-250 torr. Germane gas with a flow rate of 50 sccm / min-80 sccm / min is introduced into the epitaxial chamber 100 through a gas input device to form the second germanium thin film layer 50. The growth rate of the second germanium thin film layer 50 is 25 nm / min-35 nm / min. The optimal temperature for growing the first germanium thin film layer 20 is 350℃-400℃. Too low a temperature leads to a low growth rate, affecting production capacity; too high a temperature increases dislocation density, resulting in three-dimensional island-like growth. Within the 350℃-400℃ temperature range, the surface of the first germanium thin film layer 20 is smooth, avoiding island defects and releasing most of the elastic strain. The optimal temperature for growing the second germanium thin film layer 50 is 550℃-600℃. Since the second germanium thin film layer 50 is grown on the first germanium thin film layer 20, and the amorphous material layer 40 effectively blocks the extension of penetrating dislocations 21 in the first germanium thin film layer 20, the second germanium thin film layer 50 can grow under high dislocation suppression conditions. Therefore, the process temperature for growing the second germanium thin film layer 50 can be appropriately increased to increase its growth rate. This process design not only improves growth efficiency but also ensures the crystal quality of the second germanium thin film layer 50, guaranteeing the high performance of germanium photoelectric detectors.

[0049] The deposition chamber 200 is used to deposit an amorphous material layer 40 on the surface of the first germanium thin film layer 20 and within the pit 30. In some embodiments, the deposition chamber 200 is any one of a plasma-enhanced chemical vapor deposition (PECVD) chamber, a physical vapor deposition (PVD) chamber, and an atomic layer deposition (ALD) chamber. In this example, the deposition chamber 200 is a PECVD chamber. PECVD significantly reduces its dependence on temperature by activating the reaction through plasma (high-energy particles in the plasma can reduce the activation energy of the reaction), and has the outstanding advantage of low deposition temperature. The PECVD process can complete the deposition of the amorphous material layer 40 in a low-temperature range of 200℃-400℃, avoiding the extension of penetrating dislocations 21 in the first germanium thin film layer 20 under high-temperature conditions, while ensuring the uniformity and density of the amorphous material layer 40, providing support for the high-quality epitaxial growth of the subsequent second germanium thin film layer 50.

[0050] A pre-cleaning chamber 300 is used to etch the amorphous material layer 40 on the surface of the first germanium thin film layer 20. Since the amorphous material layer 40 is deposited on the inner surface of the pit 30, an amorphous material layer 40 will inevitably be deposited on the surface of the first germanium thin film layer 20 (see...). Figure 5 This amorphous material layer 40 not only fails to provide a good nucleation surface for the growth of the second germanium thin film layer 50, but may also affect the photoelectric conversion efficiency of the device, so it needs to be etched away. The pre-cleaning chamber 300 is also used to etch away the native oxide layer and thermal oxide layer on the surface of the silicon substrate 10 before depositing the first germanium thin film layer 20, optimize the germanium-silicon interface quality, and provide good conditions for the subsequent growth of the germanium thin film.

[0051] The process steps for manufacturing germanium photodetectors using the semiconductor equipment provided by this utility model are as follows: Figure 7 As shown:

[0052] Step 1: Place the wafer loading cassette in loading area 600;

[0053] Step 2: The wafer reaches the pre-cleaning chamber 300 via the front-end module 500 and the transfer chamber 400 to remove the native oxide layer and thermal oxide layer on the surface of the silicon substrate 10.

[0054] Step 3: The wafer is transferred from the transfer chamber 400 to the epitaxial chamber 100 to form a first germanium thin film layer 20. HCl gas is introduced to etch the surface of the first germanium thin film layer 20 at the positions corresponding to the penetrating dislocations 21 to form pits 30.

[0055] Step 4: The wafer is transferred from the transfer chamber 400 to the deposition chamber 200, where an amorphous material layer 40 is deposited on the surface of the first germanium thin film layer 20 and the inner surface of the pit 30.

[0056] Step 5: The wafer is transported from the transfer chamber 400 to the pre-cleaning chamber 300, where the amorphous material layer 40 on the surface of the first germanium thin film layer 20 is etched away.

[0057] Step 6: The wafer is transferred from the transfer chamber 400 to the epitaxial chamber 100 to form a second germanium thin film layer 50. The second germanium thin film layer 50 fills the pit 30 and covers the surface of the first germanium thin film layer 20.

[0058] Step 7: The wafer is transferred back to the loading area 600 via the transfer chamber 400 and the front-end module 500.

[0059] In summary, the germanium photodetector of this invention features pits formed on the surface of the first germanium thin film corresponding to the locations of penetrating dislocations. An amorphous material layer is disposed on the inner surface of these pits. This amorphous material layer suppresses dislocation slip, effectively blocking dislocation propagation and reducing dislocation density. Furthermore, the amorphous material layer only covers the inner surface of the pits, not filling them completely, thus ensuring the device's photoelectric conversion efficiency. Additionally, integrating the epitaxial chamber, deposition chamber, and pre-cleaning chamber into the same semiconductor device via a transfer chamber for the production of germanium photodetectors reduces the contact path of external contaminants, simplifies the process flow, improves production efficiency, and optimizes space and cost.

[0060] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0061] In the description of this utility model, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0062] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0063] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0064] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above content. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A germanium photodetector device, characterized in that, Include: silicon substrate; A first germanium thin film layer is deposited on the silicon substrate; the first germanium thin film layer has a plurality of penetrating dislocations that extend through its thickness; a plurality of pits corresponding one-to-one with the plurality of penetrating dislocations are formed on the surface of the first germanium thin film layer, and the inner surface of each pit is covered with an amorphous material layer. A second germanium thin film layer is deposited on the surface of the first germanium thin film layer and on the amorphous material layer within each of the pits, and fills each of the pits.

2. The germanium photodetector device as described in claim 1, characterized in that, The depth of the pit is greater than the thickness of the amorphous material layer.

3. The germanium photodetector device as described in claim 1, characterized in that, The depth of the pit is 18nm-22nm, and the thickness of the amorphous material layer is 8nm-12nm.

4. The germanium photodetector device as described in claim 1, characterized in that, The opening width of the pit on the surface of the first germanium thin film layer is 1μm-2μm.

5. The germanium photodetector device as described in claim 1, characterized in that, The thickness of the first germanium thin film layer is 30nm-90nm, and the depth of the pit is less than the thickness of the first germanium thin film layer.

6. The germanium photodetector device as described in claim 1, characterized in that, The thickness of the second germanium thin film layer is 470nm-1410nm.

7. The germanium photodetector device as described in claim 1, characterized in that, The pit is V-shaped.

8. The germanium photodetector device as described in claim 1, characterized in that, The constituent material of the amorphous material layer is any one of SiO2, Si3N4, and SiON.

9. A semiconductor device for manufacturing a germanium photodetector as described in any one of claims 1 to 8, characterized in that, The semiconductor device includes: An epitaxial chamber is used to deposit a first germanium thin film layer on the surface of a silicon substrate, form a pit at the position corresponding to the penetrating dislocation on the surface of the first germanium thin film layer, and deposit a second germanium thin film layer on the surface of the first germanium thin film layer and on an amorphous material layer in the pit. A deposition chamber for depositing an amorphous material layer on the surface of the first germanium thin film layer and within the pit; A pre-cleaning chamber is used to etch the amorphous material layer on the surface of the first germanium thin film layer; The transfer chamber is connected to the epitaxial chamber, the deposition chamber, and the pre-cleaning chamber, respectively. The transfer chamber is equipped with a transfer device for transferring wafers between the epitaxial chamber, the deposition chamber, and the pre-cleaning chamber.

10. The semiconductor device as claimed in claim 9, characterized in that, The epitaxial chamber is provided with a gas input device, which is used to input chlorine-containing corrosive gas or fluorine-containing corrosive gas into the epitaxial chamber to form the pit, and is also used to input germane gas into the epitaxial chamber to form the first germanium thin film layer and the second germanium thin film layer.

Images