Surface composite film structure capable of cut-off longitudinal transport and conducted lateral transport, preparation method therefor and use thereof

Abstract

A surface composite film structure capable of cut-off longitudinal transport and conducted lateral transport, a preparation method therefor and the use thereof. The surface composite film structure comprises a nano dielectric layer provided on a surface of a silicon substrate, a silicon compound layer provided on the nano dielectric layer, and a polycrystalline silicon layer provided on the silicon compound layer, the material of the nano dielectric layer being a hydrogenated silicon oxide thin film, the material of the silicon compound layer being a phosphorus-containing or boron-containing hydrogenated silicon carbonitride thin film, and the material of the polycrystalline silicon layer being a phosphorus-doped or boron-doped polycrystalline silicon thin film. The surface composite film structure can achieve an excellent passivation effect, has the characteristics of being longitudinally non-conductive and laterally conductive, and has flexible and adjustable lateral sheet resistance, thus satisfying the performance requirements of silicon-based semiconductor physical devices.

Description

A surface composite film structure with longitudinal transmission cutoff and transverse transmission conduction, as well as its preparation method and application Technical Field

[0001] The present invention relates to the technical field of surface composite film structures of silicon-based semiconductor devices, and in particular to a surface composite film structure with longitudinal transmission cutoff and transverse transmission conduction, as well as a preparation method and application thereof. Background Art

[0002] Excellent and controllable surface passivation and surface carrier transport are key factors in improving the performance of silicon semiconductor physical devices. For silicon semiconductor devices, the requirements for their surfaces are diverse, and different silicon semiconductor physical devices have different requirements for surface composite film structures. Taking solar cells as an example, some cell structures, such as full back-contact solar cells, only need to achieve excellent front surface passivation and optical transmittance characteristics at the same time; some cell structures, such as front and back contact solar cells, need to achieve excellent front surface passivation, longitudinal and lateral carrier transport, and optical transmittance characteristics at the same time.

[0003] To date, the most commonly used surface composite film structures include two categories: one is the surface passivation structure, and the other is the surface passivation contact structure. The surface passivation structure uses a passivation film to achieve good passivation of the silicon surface, reducing recombination, which is manifested as a lower horizontal saturation current density (J0). The saturation current density is a physical quantity used to describe the magnitude of the surface recombination effect. The smaller the value, the smaller the surface recombination effect. However, the main problem of this structure is that the surface of the device can no longer realize the longitudinal or lateral transmission of carriers, which is manifested as an almost infinite contact resistivity (ρ c ) and sheet resistance (R sq ), contact resistivity is a measure of the ability of carriers to transport in the longitudinal direction, and sheet resistance is a measure of the ability of carriers to transport in the lateral direction. Surface passivation contact structures achieve good passivation and carrier transport on the silicon surface through passivation contact technology, which can reduce recombination, resulting in a lower level of J0. This structure can also typically achieve both longitudinal and lateral carrier transport on the surface, demonstrating device-grade ρ c (0.0001~0.1Ω.cm 2 ) and R sq (10~1000Ω / sq).

[0004] However, to date, there is no structure that can achieve excellent passivation, longitudinal non-conduction, and good lateral transmission on the surface, which limits the development of some new silicon-based semiconductor devices with special applications, such as silicon-based optoelectronic devices with new photoelectric coupling characteristics. Summary of the Invention

[0005] The purpose of the present invention is to develop a surface composite film structure that can achieve excellent passivation, longitudinal non-conduction, and good lateral transmission on the surface of a silicon wafer to meet the needs of new silicon-based semiconductor physical devices.

[0006] To achieve the above objectives, the first aspect of the present invention provides a surface composite film structure that cuts off vertical transmission and conducts lateral transmission, comprising a nano-dielectric layer disposed on the surface of a silicon substrate, a silicide layer disposed on the nano-dielectric layer, and a polysilicon layer disposed on the silicide layer, wherein the material of the nano-dielectric layer is a hydrogenated silicon oxide film, the material of the silicide layer is a hydrogenated carbon nitride silicon film containing phosphorus or boron, and the material of the polysilicon layer is a phosphorus-doped or boron-doped polysilicon film.

[0007] The surface composite film structure of the present invention can achieve an excellent passivation effect, and has the characteristics of longitudinal non-conduction and lateral conduction, and the lateral square resistance is flexibly adjustable, meeting the performance requirements of new silicon-based semiconductor physical devices.

[0008] Furthermore, the refractive index of the silicide layer is 1.5 to 3.0, and the transmittance of the silicide layer above 400 nm is greater than 97%. The refractive index of the silicide layer can be controlled by adjusting the composition, and it has extremely low optical absorption characteristics.

[0009] Furthermore, the carbon concentration of the silicide layer is 1×10 21 cm -3 ~2×10 22 cm -3 , nitrogen concentration is 5×10 21 cm -3 ~4×10 22 cm -3 .

[0010] Furthermore, the phosphorus / boron concentration of the silicide layer is 1×10 19 cm -3 ~1×10 21 cm -3 The phosphorus / boron concentration of the silicide layer can be adjusted, thereby achieving control over the transport properties of the surface composite film structure.

[0011] Furthermore, the thickness of the nano-medium layer is 1 to 20 nm, and the thickness of the silicide layer is greater than 10 nm. The surface composite film structure can achieve controllable adjustment of optical absorption and transmission properties by adjusting parameters such as the refractive index and film thickness of the silicide layer and the polysilicon layer.

[0012] Furthermore, the hydrogen concentration of the nano-medium layer is 1×10 19 cm -3 ~1×10 22 cm -3, the hydrogen concentration of the silicide layer is 1×10 19 cm -3 ~1×10 22 cm -3 Each layer of the surface composite film structure has a high hydrogen concentration and good chemical stability, which can achieve excellent surface protection for silicon wafers.

[0013] Furthermore, the material of the polysilicon layer is a phosphorus-doped polysilicon film with an activation concentration range of 1×10 19 cm -3 ~1×10 21 cm -3 , or the material of the polysilicon layer is a boron-doped polysilicon film with an activation concentration range of 5×10 18 cm -3 ~5×10 20 cm -3 The sheet resistance of the composite film can be adjusted by adjusting the doping concentration of the polysilicon layer.

[0014] Furthermore, the silicon substrate contains hydrogen, carbon and nitrogen, and the concentration of each element gradually decreases from the surface to the body. The hydrogen concentration on the surface of the silicon substrate is 1×10 19 cm -3 ~1×10 21 cm -3 , the nitrogen concentration is 1×10 19 cm -3 ~1×10 22 cm -3 , the carbon concentration is 1×10 19 cm -3 ~1×10 22 cm -3 Carbon and nitrogen atoms can effectively capture hydrogen atoms and inject them into the substrate and interface to passivate more defect states; the introduction of elements such as carbon and nitrogen near the surface of the silicon wafer can improve the mechanical properties of the silicon wafer.

[0015] Furthermore, a hydrogen-rich dielectric layer is provided between the silicide layer and the polysilicon layer. The material of the hydrogen-rich dielectric layer is selected from one or more stacked films selected from hydrogenated aluminum oxide film, hydrogenated silicon nitride film, hydrogenated silicon oxynitride film, and hydrogenated silicon oxide film. Adding the hydrogen-rich dielectric layer can improve the passivation performance of the surface composite film structure.

[0016] A second aspect of the present invention provides a method for preparing the surface composite membrane structure with longitudinal transmission cutoff and transverse transmission conduction, comprising the following steps:

[0017] S1, cleaning silicon substrate;

[0018] S2, preparing a silicon oxide film on the surface of the silicon substrate;

[0019] S3, depositing an amorphous silicide film containing carbon and nitrogen elements;

[0020] S4, depositing an amorphous silicon film doped with phosphorus or boron;

[0021] S5, performing a high-temperature annealing process to diffuse carbon and nitrogen elements into the silicon substrate and transform the phosphorus- or boron-doped amorphous silicon film into a polycrystalline silicon film;

[0022] S6. Perform hydrogenation treatment.

[0023] The preparation method of the surface composite membrane structure of the present invention is fully compatible with existing battery production line technology and has good mass production application prospects. The surface composite membrane structure has good thermal stability, and its passivation quality is not affected by temperature within a temperature range not exceeding 500°C.

[0024] Furthermore, between steps S2 and S3, there is a step of depositing one or more stacked films of aluminum oxide, silicon nitride, silicon oxide, and silicon oxynitride.

[0025] A third aspect of the present invention provides a silicon-based semiconductor device comprising the aforementioned surface composite film structure that blocks vertical transmission and conducts lateral transmission. This surface composite film structure exhibits excellent surface passivation and possesses the characteristics of being non-conductive in the vertical direction and conductive in the lateral direction, thereby improving the performance of silicon-based semiconductor devices.

[0026] In summary, the present invention has the following beneficial effects compared to the prior art:

[0027] (1) The surface composite film structure of the present invention has the characteristics of longitudinal transmission cutoff and lateral transmission conduction, and the lateral square resistance is flexibly adjustable, which can meet the performance requirements of new silicon-based semiconductor devices.

[0028] (2) The surface composite film structure of the present invention does not use transparent conductive film materials (TCO) at all, avoiding the negative effects of some common high-quality TCOs, such as the use of rare metal In in ITO, water absorption and instability of AZO, and significant parasitic absorption of TTO. At the same time, the preparation method does not require the use of magnetron sputtering equipment.

[0029] (2) The refractive index and film thickness of the silicide layer and the polysilicon layer of the surface composite film structure of the present invention are adjustable, thereby achieving controllable adjustment of optical absorption and transmission characteristics.

[0030] (3) The surface composite film structure of the present invention has excellent surface passivation effect and body passivation effect, which can reduce the saturation current density on the surface of the silicon wafer and increase the body life.

[0031] (4) The components of the surface composite film structure of the present invention include elements such as silicon, nitrogen, and carbon, which have good chemical and thermal stability and can achieve excellent surface protection for silicon wafers. Within the temperature range below 500°C, the passivation quality is not affected by temperature.

[0032] (5) The surface composite film structure of the present invention can introduce elements such as carbon and nitrogen into the near surface of the silicon wafer, which is beneficial to improving the mechanical properties of the silicon wafer.

[0033] (6) The preparation method of the surface composite membrane structure of the present invention is fully compatible with existing preparation technology, has no ion bombardment damage, has low material cost, and has good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG1 is a schematic structural diagram of a surface composite membrane structure in a specific embodiment of the present invention.

[0035] FIG2 is a schematic structural diagram of another surface composite membrane structure in a specific embodiment of the present invention.

[0036] FIG3 is a process flow chart of a surface composite membrane structure in a specific embodiment of the present invention.

[0037] Explanation of reference numerals: 1-silicon substrate, 2-nano dielectric layer, 3-silicide layer, 4-polysilicon layer, 5-hydrogen-rich dielectric layer. DETAILED DESCRIPTION

[0038] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. It should be noted that the following embodiments are only intended to illustrate the implementation methods and typical parameters of the present invention, and are not intended to limit the parameter ranges described in the present invention. Reasonable variations derived therefrom are still within the scope of protection of the claims of the present invention.

[0039] It should be noted that the endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0040] The present invention provides a surface composite film structure that has the characteristics of vertical transmission cutoff and lateral transmission conduction. The typical structure of the surface composite film structure is shown in Figure 1 and includes a nano-dielectric layer 2, a silicide layer 3, and a polysilicon layer 4 stacked sequentially on the surface of a silicon substrate 1.

[0041] The material of the nano-medium layer 2 is a hydrogenated silicon oxide film, the main components of which are silicon, oxygen, and hydrogen. The hydrogen concentration in the nano-medium layer 2 is >1×10 19 cm -3 , the typical hydrogen concentration range is 1×10 19 cm -3 ~1×10 22 cm -3 Its thickness is above 1 nm, with a typical thickness range of 1 to 20 nm, and preferably a thickness of 1 to 2 nm. The transmittance of the nano-medium layer 2 above 400 nm is greater than 97%, and the absorption coefficient k value decreases to nearly 0 at wavelengths above 400 nm, showing extremely low optical absorption characteristics.

[0042] The material of the silicide layer 3 is a hydrogenated carbon nitride silicon film containing phosphorus or boron, with the main components being silicon, nitrogen, carbon, hydrogen, phosphorus, or boron; the silicide layer 3 may also contain oxygen. Its thickness is greater than 10nm. The silicide layer 3 has a transmittance greater than 97% above 400nm, and an absorption coefficient k value that decreases to nearly zero at wavelengths above 400nm, demonstrating extremely low optical absorption characteristics. The carbon concentration of the silicide layer is 1×10 21 cm - 3 ~2×10 22 cm -3 , nitrogen concentration is 5×10 21 cm -3 ~4×10 22 cm -3 The ratio of carbon, nitrogen and other elements in the silicide layer 3 can be adjusted, and its refractive index ranges from 1.5 to 3.0, which can be adjusted according to the composition. The boron / phosphorus concentration in the silicide layer 3 can be adjusted, and the typical concentration range is 1×10 19 cm -3 ~1×10 21 cm -3 The hydrogen concentration in the silicide layer 3 is >1×10 19 cm -3 , with a typical concentration range of 1×10 19 cm -3 ~1×10 22 cm -3 .

[0043] The material of the polysilicon layer 4 is a phosphorus-doped or boron-doped polysilicon film. The activation concentration range of the phosphorus-doped polysilicon film is generally 1×10 19 ~1×10 21 ~cm -3 , the activation concentration range of boron-doped polysilicon film is 5×10 18 cm -3 ~5×10 20 cm -3The thickness of the polysilicon layer 4 is adjustable, and by adjusting the thickness, the transmittance of the surface composite film structure can be changed.

[0044] The silicon substrate 1 contains hydrogen, nitrogen, carbon, phosphorus or boron near the surface and in the bulk region, and the concentration of the corresponding elements gradually decreases from the surface to the bulk. Among them, the nitrogen concentration in the surface region below the nano-medium layer 2 is generally higher than 1×10 19 cm -3 , with a typical concentration range of 1×10 19 cm -3 ~1×10 22 cm -3 ; Carbon concentration is generally higher than 1×10 19 cm - 3 , with a typical concentration range of 1×10 19 cm -3 ~1×10 22 cm -3 ; Hydrogen concentration is generally higher than 1×10 19 cm -3 , with a typical concentration range of 1×10 19 cm -3 ~1×10 21 cm -3 .

[0045] As shown in FIG2 , another typical surface composite film structure includes a nano-dielectric layer 2, a silicide layer 3, a hydrogen-rich dielectric layer 5, and a polysilicon layer 4 stacked sequentially on the surface of a silicon substrate 1. The properties of the silicon substrate 1, nano-dielectric layer 2, silicide layer 3, and polysilicon layer 4 are the same as those of the surface composite film structure in the aforementioned embodiment.

[0046] The material of the hydrogen-rich dielectric layer 4 is hydrogenated aluminum oxide, hydrogenated silicon nitride, hydrogenated silicon oxide, hydrogenated silicon oxynitride or a combination thereof. The hydrogen concentration of the hydrogen-rich dielectric layer 4 is in the range of 1×10 20 cm - 3 ~1×10 22 cm -3 The hydrogen-rich dielectric layer may also contain boron or phosphorus elements.

[0047] As shown in FIG3 , a typical method for preparing the surface composite membrane structure includes the following steps:

[0048] S1. Perform standard RCA cleaning on the silicon substrate.

[0049] S2. Prepare a silicon oxide film on the surface of the silicon substrate. The preparation methods include wet chemical method, plasma assisted oxidation method, thermal oxidation method, ozone oxidation method, etc.

[0050] S3. Depositing an amorphous silicide film containing carbon and nitrogen elements on the silicon oxide film. The typical preparation method is PECVD in-situ deposition method, and the deposition temperature range is 100°C to 600°C.

[0051] S4. Depositing a phosphorus- or boron-doped amorphous silicon film on the amorphous silicide film; or first depositing a hydrogen-rich dielectric layer on the amorphous silicide film, and then depositing a phosphorus- or boron-doped amorphous silicon film on the hydrogen-rich dielectric layer.

[0052] S5. Perform high-temperature annealing to diffuse carbon and nitrogen into the silicon substrate and transform the phosphorus- or boron-doped amorphous silicon film into a polycrystalline silicon film. The typical temperature range is 600° C. to 1200° C., preferably 900° C. to 950° C.

[0053] S6. Perform hydrogenation treatment. The hydrogenation treatment includes: performing annealing or light annealing in a hydrogen-containing atmosphere to achieve hydrogen injection; or depositing a hydrogen-rich dielectric film, followed by low-temperature annealing, and then cleaning and etching to remove the hydrogen-rich dielectric film.

[0054] The above-mentioned surface composite film structure has excellent surface passivation effect, and has the characteristics of longitudinal non-conduction and lateral conduction. It is suitable for new silicon-based semiconductor devices. Its preparation method is fully compatible with existing production line technology, has low preparation cost, high stability, and has good industrial application prospects.

[0055] The technical solutions and effects of the present invention are described below through specific embodiments.

[0056] Example 1

[0057] Prepare n-type silicon wafers, flat, 110μm thick, with a resistivity of 1-7Ω·cm. After standard RCA cleaning, the silicon wafers are placed in a PECVD chamber and N2O plasma is used to prepare SiO x film, and then deposited a 10nm nitrogen-rich and carbon-rich amorphous silicon film (carbon concentration of 1×10 22 cm -3 , the nitrogen concentration is 1×10 22 cm -3 ), and then deposited a 30nm phosphorus-doped amorphous silicon film; annealed at 900℃ for 30min in a tube furnace; and finally annealed at 400℃ for 60min in a mixed gas atmosphere of nitrogen and hydrogen. Six samples were prepared and Sinton test was performed. The single-side saturation current density J 0,s The test results range is 0.5~1fA / cm 2 The lateral sheet resistance ranges from 1000 to 1600Ω / sq, the longitudinal contact resistivity cannot be measured, and the transmittance at a wavelength of 400nm is approximately 90%.

[0058] Example 2

[0059] Prepare n-type silicon wafers, flat, 110μm thick, with a resistivity of 1-7Ω·cm. After standard RCA cleaning, the silicon wafers are placed in a PECVD chamber and N2O plasma is used to prepare SiO x film, and then deposited a 10nm nitrogen-rich and carbon-rich amorphous silicon film (carbon concentration of 2×10 22 cm -3 , nitrogen concentration is 5×10 21 cm -3 ), and then deposited 200nm phosphorus-doped amorphous silicon film; annealed at 900℃ for 30min in a tube furnace; and finally annealed at 400℃ for 60min in a mixed gas atmosphere of nitrogen and hydrogen. 6 samples were prepared and Sinton test was performed. The single-side saturation current density J 0,s The test results range is 1.0~2.0fA / cm 2 The lateral sheet resistance ranges from 20 to 40Ω / sq, the longitudinal contact resistivity cannot be measured, and the transmittance at a wavelength of 400nm is approximately 50%.

[0060] Example 3

[0061] Prepare n-type silicon wafers, flat, 110μm thick, with a resistivity of 1-7Ω·cm. After standard RCA cleaning, the silicon wafers are placed in a PECVD chamber and N2O plasma is used to prepare SiO x film, and then deposited a 10nm nitrogen-rich and carbon-rich amorphous silicon film (carbon concentration of 1×10 22 cm -3 , the nitrogen concentration is 1×10 22 cm -3 ); then ALD deposits AlO x , then transferred to PECVD to deposit SiN x ; Deposit 30nm phosphorus-doped amorphous silicon film; anneal at 900℃ for 30min in a tube furnace; then ALD deposit AlO x , then transferred to PECVD to deposit SiN x Hydrogenation treatment was performed; then AlO x / SiN x Etching. Prepare 6 samples and conduct Sinton test. The single-side saturation current density J 0,s The test results range is 0.2~0.5fA / cm 2 The lateral sheet resistance ranges from 1000 to 1600Ω / sq, the longitudinal contact resistivity cannot be measured, and the transmittance at a wavelength of 400nm is approximately 90%.

[0062] Example 4

[0063] Prepare n-type silicon wafers, flat, 110μm thick, with a resistivity of 1-7Ω·cm. After standard RCA cleaning, the silicon wafers are placed in a PECVD chamber and N2O plasma is used to prepare SiO x film, and then deposited a 10nm nitrogen-rich and carbon-rich amorphous silicon film (carbon concentration of 1×10 21 cm -3 , nitrogen concentration is 3×10 22 cm -3 ), then deposit SiN x , then deposit 200nm phosphorus-doped amorphous silicon film; anneal at 900℃ for 30min in a tube furnace; then ALD deposit AlO x , then transferred to PECVD to deposit SiN x Hydrogenation treatment was performed; then AlO x / SiN x Etching. Prepare 6 samples and conduct Sinton test. The single-side saturation current density J 0,s The test results range is 0.5~1.2fA / cm 2 The lateral sheet resistance ranges from 20 to 40Ω / sq, the longitudinal contact resistivity cannot be measured, and the transmittance at a wavelength of 400nm is approximately 50%.

[0064] Comparative Example 1

[0065] Prepare n-type silicon wafer, flat, 110μm thick, resistivity 1-7Ω·cm. After standard RCA cleaning, place it in the ALD chamber and deposit AlO x ; Then transferred to a tube furnace and annealed at 450℃ for 30min under nitrogen atmosphere. 6 samples were prepared and Sinton test was performed. The single-side saturation current density J 0,s The test results range is 3.0~5.0fA / cm 2 , both the longitudinal contact resistivity and the lateral sheet resistance cannot be measured.

[0066] Comparative Example 2

[0067] Prepare n-type silicon wafer, flat, 110μm thick, resistivity 1-7Ω·cm. After standard RCA cleaning, place it in the ALD chamber and deposit AlO x ; Then transferred to a tube furnace and annealed at 450℃ for 30min under nitrogen atmosphere; transferred to PECVD to deposit SiN x Finally, the samples were transferred to a tube furnace and annealed at 400℃ for 60min in a nitrogen / hydrogen mixed gas. Six samples were prepared and Sinton test was performed. The single-side saturation current density J 0,s The test results range is 2.0~4.0fA / cm 2 , both the longitudinal contact resistivity and the lateral sheet resistance cannot be measured.

[0068] Comparative Example 3

[0069] Prepare n-type silicon wafers, flat, 110 μm thick, with a resistivity of 1-7 Ω·cm. After standard RCA cleaning, the silicon wafers were placed in a tube furnace and prepared in an oxygen atmosphere. x ; Then transferred to the PECVD chamber to deposit SiN x Finally, annealing was carried out at 400℃ for 60min in a tube furnace under a mixture of nitrogen and hydrogen. Six samples were prepared and Sinton test was carried out. The single-side saturation current density J 0,s The test results range is 8.0~12.0fA / cm 2 , both the longitudinal contact resistivity and the lateral sheet resistance cannot be measured.

[0070] Comparative Example 4

[0071] Prepare n-type silicon wafers, flat, 110 μm thick, with a resistivity of 1-7 Ω·cm. After standard RCA cleaning, the silicon wafers were placed in a tube furnace and prepared in an oxygen atmosphere. x ; Then transferred to the PECVD chamber to deposit SiN x ; Annealing at 400℃ for 60min in a nitrogen / hydrogen mixture; then a layer of ITO film with a thickness of about 60nm was deposited on the surface by magnetron sputtering. 6 samples were prepared and Sinton test was performed. The single-side saturation current density J 0,s The test results range from 20 to 40 fA / cm 2 The lateral sheet resistance ranges from 40 to 60Ω / sq, and the longitudinal contact resistivity cannot be measured.

[0072] Comparative Example 5

[0073] Prepare n-type silicon wafers, flat, 110 μm thick, with a resistivity of 1-7 Ω·cm. After standard RCA cleaning, the silicon wafers were placed in a tube furnace and prepared in an oxygen atmosphere. x ; Then transferred to the PECVD chamber to deposit 120nm of phosphorus-doped amorphous silicon; then annealed at 900℃ for 30min in a nitrogen / hydrogen mixed gas atmosphere in a tube furnace; finally annealed at 400℃ for 60min in a nitrogen and hydrogen mixed gas atmosphere. 6 samples were prepared and Sinton test was performed. The single-side saturation current density J 0,s The test results range is 1.0~3.0fA / cm 2 , the lateral sheet resistance range is 30~50Ω / sq, and the longitudinal contact resistivity range is 0.001~0.003Ωcm 2 .

[0074] Comparative Example 6

[0075] Prepare n-type silicon wafers, flat, 110 μm thick, with a resistivity of 1-7 Ω·cm. After standard RCA cleaning, the silicon wafers were placed in a tube furnace and prepared in an ozone atmosphere. x ; Then transferred to the PECVD chamber to deposit 120nm of phosphorus-doped amorphous silicon; then annealed at 880℃ for 30min in a nitrogen / hydrogen mixed gas atmosphere in a tube furnace; finally annealed at 400℃ for 60min in a nitrogen and hydrogen mixed gas atmosphere. 6 samples were prepared and Sinton test was performed. The single-side saturation current density J 0,s The test results range is 6.0~10.0fA / cm 2 , the lateral sheet resistance range is 50~70Ω / sq, and the longitudinal contact resistivity range is 0.002~0.004Ωcm 2 .

[0076] Comparison of the single-side saturation current density (J) of the passivation sheets prepared in Examples 1-4 and Comparative Examples 1-6 0,s ), lateral sheet resistance, and longitudinal contact resistivity, as shown in Table 1. The results show that the surface composite film structure of the present invention has an excellent passivation effect, can significantly reduce the saturation current density on the surface of the silicon wafer, and has the characteristics of longitudinal non-conduction and lateral conduction.

[0077] Table 1 Comparison of passivation sheet performance of Examples 1-4 and Comparative Examples 1-6

[0078] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A surface composite film structure that is longitudinally transmissive and laterally conductive, characterized in that, It includes a nano dielectric layer disposed on the surface of a silicon substrate, a silicide layer disposed on the nano dielectric layer, and a polysilicon layer disposed on the silicide layer. The material of the nano dielectric layer is a silicon oxide hydride thin film, the material of the silicide layer is a carbon, nitrogen, and silicon hydride thin film containing phosphorus or boron, and the material of the polysilicon layer is a phosphorus-doped or boron-doped polysilicon thin film.

2. The surface composite film structure according to claim 1, wherein The refractive index of the silicide layer is 1.5 to 3.0, and the transmittance of the silicide layer above 400 nm is greater than 97%.

3. The surface composite film structure according to claim 1, wherein The carbon concentration of the silicide layer is 1×10 21 cm -3 ~2×10 22 cm -3 , and the nitrogen concentration is 5×10 21 cm -3 ~4×10 22 cm -3 .

4. The surface composite film structure according to claim 1, characterized in that The phosphorus / boron concentration of the silicide layer is 1×10 19 cm -3 ~1×10 21 cm -3 。 5. The surface composite film structure according to claim 1, wherein, The thickness of the nano dielectric layer is 1 to 20 nm, and the thickness of the silicide layer is greater than 10 nm.

6. The surface composite film structure according to claim 1, characterized in that, The hydrogen concentration of the nano-medium layer is 1×10 19 cm -3 ~1×10 22 cm -3 , and the hydrogen concentration of the silicide layer is 1×10 19 cm - 3 ~1×10 22 cm -3 .

7. The surface composite film structure according to claim 1, wherein The material of the polysilicon layer is a phosphorus-doped polysilicon thin film with an activation concentration range of 1×10 19 cm -3 ~1×10 21 cm -3 , or the material of the polysilicon layer is a boron-doped polysilicon thin film with an activation concentration range of 5×10 18 cm - 3 ~5×10 20 cm -3 。 8. The surface composite film structure according to claim 1, characterized in that, The silicon substrate contains hydrogen, carbon, and nitrogen elements, and the concentrations of these elements gradually decrease from the surface to the interior. The hydrogen concentration on the surface of the silicon substrate is 1×10 19 cm -3 ~1×10 21 cm -3 , the nitrogen concentration is 1×10 19 cm -3 ~1×10 22 cm -3 , and the carbon concentration is 1×10 19 cm -3 ~1×10 22 cm -3 .

9. The surface composite film structure according to any one of claims 1-8, characterized in that A hydrogen-rich dielectric layer is provided between the silicide layer and the polysilicon layer, and the material of the hydrogen-rich dielectric layer is selected from one or more laminated thin films of aluminum oxide hydride thin film, silicon nitride hydride thin film, silicon oxynitride hydride thin film, and silicon oxide hydride thin film.

10. A method for preparing a surface composite film structure with longitudinal transmission cutoff and transverse transmission conduction as described in any one of claims 1-9, characterized in that, It includes the following steps: S1. Clean the silicon substrate; S2. Prepare a silicon oxide thin film on the surface of the silicon substrate; S3. Deposit an amorphous silicide thin film containing carbon and nitrogen elements; S ​ ​ 11. The preparation method according to claim 10, characterized in that, ​ 12. A silicon-based semiconductor device, characterized in that, ​

Images