A method for preparing high-performance BPSG thin films without an AMPLE transfer buffer tank using the AMAT Centura 5200 PECVD equipment

Abstract

The application discloses a high-performance BPSG film preparation method based on an AMAT Centura 5200 PECVD device without an AMPLE transfer buffer tank, and belongs to the technical field of semiconductor integrated circuit film manufacturing. The method adopts SiH4, B2H6, PH3 and N2O gas-phase precursors to deposit a BPSG film in a Centura 5200 deposition cavity without an AMPLE transfer buffer tank and a matched liquid source liquid supply system, a high-density plasma environment is constructed by setting a process window of a radio frequency power of 300 W to 800 W and a cavity pressure of 2 Torr to 8 Torr, a virtual buffer effect is formed to replace a physical buffer tank, and the uneven gas mixing defect caused by the absence of the buffer tank is compensated; the deposited film is subjected to reflow annealing at 950 DEG C for 30 min under a nitrogen protection atmosphere. The application completely cancels the AMPLE transfer buffer tank, eliminates film carbon impurities, the residual carbon content is less than or equal to 10 ppm, there is no carbon-wrapped closed micropore in the film, the interface state density is reduced, the dielectric breakdown life is improved over time, and the hardware procurement and operation and maintenance costs are greatly reduced.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor integrated circuit thin film manufacturing technology, specifically relating to a method for preparing high-performance BPSG thin films based on an AMAT Centura 5200 PECVD equipment without an AMPLE transfer buffer tank. Background Technology

[0002] The mass production of BPSG thin films on semiconductor production lines is divided into two major process systems.

[0003] One system is the TMB / TMP organic liquid source system, which uses trimethyl borate (TMB) and trimethyl phosphate (TMP) as boron and phosphorus doping precursors, respectively, and combines them with tetraethyl orthosilicate (TEOS) silicon source for BPSG deposition. Because TMB / TMP are high-viscosity liquid chemicals, their vaporization uniformity is poor and their gas supply stability is insufficient. Therefore, the entire liquid supply system must be equipped with an AMPLE transfer buffer tank. This tank integrates raw material storage, real-time liquid level monitoring, automatic liquid replenishment, constant-temperature vaporization, and pressure delivery into a single hardware unit. By buffering and stabilizing the pressure and homogenizing the airflow, it solves the problem of uneven vaporization and mixing of the liquid source, making it an indispensable dedicated supporting equipment for organic source processes. While this method offers excellent native step coverage in thin films, it suffers from three major drawbacks: First, TMB / TMP molecules contain methyl groups, which easily lead to carbon impurities during deposition, leaving a large amount of residual carbon impurities in the native film. Even after high-temperature reflow annealing at 950℃ for 30min, carbon-encapsulated nanopores remain within the film, resulting in a high defect density at the Si / BPSG interface and poor high-temperature bias reliability due to dielectric breakdown (TDDB). Second, the AMPLE transfer buffer tank itself has high procurement costs, and the accompanying seals, filters, heating pipes, and level sensors are high-frequency consumables, leading to high annual maintenance and consumable replacement costs for the production line. Third, regular tank purging, pipe leak detection, and chemical replenishment are required, which consumes machine production time, reduces equipment uptime, and poses risks of organic chemical leakage and pipe crystallization blockage.

[0004] The second approach is the B2H6 / PH3 hydride gas-phase source system, which uses silane (SiH4), diborane (B2H6), and phosphine (PH3) gas-phase sources to deposit BPSG. The precursors themselves contain no carbon. However, this system has inherent technical limitations: the hydride gas-phase particles have a long mean free path and a high gas flow rate. Furthermore, traditional hydride processes do not incorporate any buffering or voltage stabilization equipment. By completely abandoning the AMPLE transfer buffer tank, the mixing time of various reactive gases after entering the deposition chamber is short, resulting in extremely poor mixing uniformity. This directly leads to insufficient film deposition uniformity, weak coverage of native steps, and poor film density.

[0005] Reference Figure 1In the existing TMB / TMP organic source liquid supply system, TMB liquid cylinders and TMP liquid cylinders are connected to the AMPLE transfer buffer tank via replenishment pipelines and automatic replenishment valve groups. The AMPLE transfer buffer tank has a built-in constant temperature heating layer and a liquid level sensor, and the tank outlet leads to the PECVD deposition chamber via a vaporization heating pipeline. This system has a complex structure, high hardware costs, and cumbersome operation and maintenance.

[0006] In summary, the existing technologies have the following drawbacks: organic source processes rely on expensive AMPLE transfer buffer tank hardware, resulting in high maintenance costs, severe carbon defects in the thin film, and poor long-term device reliability; although traditional hydride processes have carbon-free gas sources, the lack of a buffer tank leads to uneven gas mixing and poor process stability, and simply replacing the gas source cannot produce high-performance thin films; there is currently no process solution that can simultaneously completely eliminate the entire AMPLE transfer buffer tank hardware, eliminate carbon impurities in the thin film, match the standard reflow annealing process of the production line, and achieve thin film performance that surpasses traditional organic source solutions. Summary of the Invention

[0007] This invention provides a method for preparing BPSG thin films without an AMPLE transfer buffer tank based on an AMAT Centura 5200 PECVD equipment, comprising the following steps: S1, providing a semiconductor substrate and feeding the substrate into the Centura 5200 parallel-plate plasma deposition chamber, depositing a BPSG thin film using SiH4, B2H6, PH3, and N2O vapor precursors; controlling the B and P doping mass percentages within the film to be completely consistent with the doping parameters of a reference BPSG thin film prepared using a TMB / TMP organic source and a matching AMPLE transfer buffer tank automatic replenishment system; S2, performing reflow annealing on the deposited BPSG thin film: under a nitrogen protective atmosphere, annealing temperature 950℃, and holding at that temperature for 30 minutes; S3, after reflow annealing, directly proceeding to subsequent etching, chemical mechanical polishing, or metallization processes; the entire process does not require or use a dedicated TMB / TMP AMPLE transfer buffer tank or a matching automatic replenishment vaporization system. The AMPLE transfer buffer tank is an integrated transfer tank specifically designed for storing and transporting liquid TMB / TMP. It integrates liquid level sensing, automatic liquid replenishment, constant temperature heating, and gas phase delivery valve group. The residual carbon impurities in the hydride source BPSG film after reflux annealing are ≤10ppm, and there are no carbon-encapsulated closed micropores in the film. The reliability of the film interface leakage and dielectric breakdown over time is better than that of TMB / TMP organic source BPSG films with the same doping amount and equipped with the AMPLE transfer buffer tank. The deposition chamber adopts a customized power-pressure process window, and a virtual buffering effect is constructed through a high-density plasma environment to compensate for the gas mixing unevenness defects caused by the absence of the AMPLE transfer buffer tank, ensuring the uniformity and density of film deposition.

[0008] Furthermore, the deposition process parameters for the Centura 5200 deposition chamber are as follows: RF power 300W~800W, chamber pressure 2Torr~8Torr; SiH4 flow rate 50sccm~200sccm, B2H6 dilution gas flow rate 10sccm~50sccm, PH3 dilution gas flow rate 15sccm~60sccm, and N2O flow rate 500sccm~2000sccm.

[0009] Furthermore, in the reflux annealing process: the N2 carrier gas flow rate is 5 slm to 20 slm, the heating rate is 5℃ / min to 10℃ / min, and the cooling rate is 3℃ / min to 8℃ / min.

[0010] Furthermore, the BPSG film has a boron doping mass fraction of 2.0 wt% to 5.0 wt% and a p doping mass fraction of 2.5 wt% to 6.0 wt%.

[0011] Furthermore, the BPSG thin film is used as a metal front dielectric layer for logic ICs, power devices, or memory chips.

[0012] Furthermore, the Centura 5200 deposition chamber has a radio frequency power of 500W and a chamber pressure of 4Torr.

[0013] Furthermore, the BPSG thin film has a boron doping mass fraction of 3.2 wt% and a p doping mass fraction of 3.8 wt%.

[0014] Furthermore, the TMB / TMP liquid source supply branch of the deposition chamber has been removed before the deposition step, and the AMPLE transfer buffer tank and its matching automatic liquid replenishment and vaporization supply system have been removed.

[0015] Furthermore, the interface state Dit of the BPSG film after reflow annealing at 950℃ for 30 min is ≤1.2×10⁻⁶. 10 cm -2 ·eV -1 .

[0016] Furthermore, the BPSG film has a residual carbon content of 6 ppm after reflow annealing.

[0017] This invention creates a virtual buffer effect by optimizing the power and pressure process windows, replacing the traditional physical buffer tank hardware of the AMPLE. It completely removes the entire TMB / TMP AMPLE transfer buffer tank, level control system, heating and vaporization pipeline, and replenishment valve assembly, thus eliminating the costs of tank procurement, annual seal and filter replacement, and regular pipeline cleaning and maintenance. It also eliminates the costs of purchasing organic source chemicals and replacing pipelines due to crystallization blockage, significantly reducing the overall manufacturing cost per wafer. Simultaneously, without the introduction of organic carbon precursors, residual carbon after reflow annealing is ≤10ppm, resulting in no carbon clusters within the film and carbon-encapsulated nanopores, leading to a dense and uniform film microstructure. There is no carbon impurity segregation at the Si / BPSG interface, significantly reducing the interface state density (Dit), resulting in less shallow junction leakage and device threshold voltage drift. The high-temperature bias TDDB lifetime is more than 30% higher than that of organic source AMPLE solutions. The B and P doping concentrations remain consistent with the existing organic source benchmark. The standard 950℃ reflow annealing process remains unchanged. After reflow annealing, the high-temperature flow characteristics of the film and the step fillet flattening effect are no different from the original AMPLE process. Subsequent chemical mechanical polishing, through-hole etching, and metal interconnection processes do not require adjustment of process parameters. High-frequency maintenance steps such as AMPLE replenishment, tank leak detection, organic pipeline purging, and crystallization cleaning are eliminated, significantly reducing machine downtime, eliminating the risk of TMB / TMP organic liquid leakage and pipeline blockage, and improving the safety level and equipment uptime of the production line. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the existing TMB / TMP organic source liquid supply system.

[0019] Figure 2 This is a schematic diagram of the Centura 5200 hydride gas supply system of the present invention;

[0020] Figure 3 Comparison of the microscopic cross-sections of the two BPSG thin films after reflow annealing using transmission electron microscopy (TEM);

[0021] Figure 4 This is a flowchart comparing the process flow of the embodiments and comparative examples of the present invention;

[0022] Figure 5 A bar chart comparing TDDB lifespan and annual hardware maintenance costs. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] First Embodiment

[0025] Reference Figure 2This invention provides a method for preparing BPSG thin films without an AMPLE transfer buffer tank based on an AMAT Centura 5200 PECVD device. The method is implemented on an AMAT Centura 5200 PECVD device, which is a parallel plate plasma deposition chamber. Before deposition, the TMB / TMP liquid source supply branch is removed, and the AMPLE transfer buffer tank and its associated automatic replenishment and vaporization supply system are completely removed. The hydride cylinder 1 is directly connected to the Centura 5200 deposition chamber 2 via piping. The entire process does not involve the configuration or use of a dedicated TMB / TMP AMPLE transfer buffer tank or its associated automatic replenishment and vaporization supply system.

[0026] A semiconductor substrate with a pre-existing metal or dielectric layer is provided and fed into a Centura 5200 parallel-plate plasma deposition chamber. BPSG thin films are deposited using pure vapor-phase precursors, with SiH4, B2H6, PH3, and N2O as the gas source, without any carbon-containing organic precursors introduced throughout the process. The deposition chamber employs a customized power-pressure process window: 500W RF power, 4 Torr chamber pressure; SiH4 flow rate 50-200 sccm, B2H6 dilution gas flow rate 10-50 sccm, PH3 dilution gas flow rate 15-60 sccm, and N2O flow rate 500-2000 sccm. This power-pressure process window creates a high-density, stable plasma environment, effectively extending the gas residence time within the deposition chamber, enhancing gas collision and mixing efficiency under plasma atmosphere, and forming a virtual buffer effect to replace the physical buffer tank. This compensates for the gas mixing inhomogeneity defects caused by the lack of an AMPLE transfer buffer tank, ensuring uniform and dense film deposition. The mass percentages of B and P doping within the thin film were controlled to be completely consistent with the doping parameters of the benchmark BPSG thin film prepared using a TMB / TMP organic source and a matching AMPLE transfer buffer tank automatic replenishment system. In this embodiment, the mass fraction of B doping was 3.2 wt%, and the mass fraction of P doping was 3.8 wt%.

[0027] The deposited BPSG film is subjected to reflow annealing: nitrogen protective atmosphere, annealing temperature 950℃, constant temperature holding for 30min; N2 carrier gas flow rate 5slm~20slm, heating rate 5℃ / min~10℃ / min, cooling rate 3℃ / min~8℃ / min, the heating and cooling rates are matched with the production line standard reflow annealing process to ensure production line process compatibility.

[0028] After reflow annealing, the material is directly fed into etching, chemical mechanical polishing, or metallization processes without the need to adjust the back-end process parameters.

[0029] The hydride-sourced BPSG film, after reflow annealing at 950℃ for 30 min, had a residual carbon impurity content of 6 ppm, and no carbon-encapsulated closed micropores within the film. (Reference) Figure 3 The TEM cross-sectional images show that the BPSG film prepared by this invention has a dense and uniform microstructure without carbon-encapsulated closed pores; while the BPSG film prepared by the traditional TMB / TMP organic source process shows a large number of carbon nanopores. The film interface state Dit ≤ 1.2 × 10⁻⁶ 10 cm -2 ·eV -1 The interface leakage current, TDDB breakdown lifetime, and high-temperature storage stability are all superior to TMB / TMP organic-source BPSG films with the same doping concentration and equipped with an AMPLE transfer buffer. The mean TDDB failure time is improved by 35% compared to the comparative example.

[0030] Second Embodiment

[0031] This embodiment provides a method for preparing BPSG thin films using an AMAT Centura 5200 PECVD equipment without an AMPLE transfer buffer tank. Prior to the deposition step, the TMB / TMP liquid source supply branch in the deposition chamber has been removed, and the AMPLE transfer buffer tank and its associated automatic liquid replenishment and vaporization supply system have been removed. A semiconductor substrate is provided and fed into the Centura 5200 parallel-plate plasma deposition chamber. BPSG thin films are deposited using SiH4, B2H6, PH3, and N2O vapor precursors. The deposition process parameters are: RF power 300W, chamber pressure 8 Torr; SiH4 flow rate 200 sccm, B2H6 dilution gas flow rate 50 sccm, PH3 dilution gas flow rate 60 sccm, and N2O flow rate 2000 sccm. The boron doping mass fraction is controlled at 2.0 wt%, and the p-doping mass fraction at 2.5 wt%.

[0032] The deposited BPSG film was subjected to reflow annealing: nitrogen protective atmosphere, annealing temperature 950℃, constant temperature holding for 30 min; N2 carrier gas flow rate 5 slm, heating rate 5℃ / min, cooling rate 3℃ / min.

[0033] After reflow annealing, the film proceeds directly to subsequent etching, chemical mechanical polishing, or metallization processes. No dedicated TMB / TMP AMPLE transfer buffer tank or associated automatic liquid replenishment and vaporization supply system is used throughout the process. The residual carbon impurities in the BPSG film after reflow annealing are ≤10ppm, and there are no carbon-encapsulated closed micropores within the film. The film exhibits superior interfacial leakage current and TDDB breakdown reliability compared to TMB / TMP organic-source BPSG films with the same doping concentration and equipped with an AMPLE transfer buffer tank.

[0034] This embodiment, through a process window combination of a relatively low RF power of 300W and a relatively high cavity pressure of 8 Torr, can also construct an effective high-density plasma environment to form a virtual buffering effect. This power-pressure parameter is located at the boundary of the process window defined in this invention. Under low power conditions, by increasing the cavity pressure to extend the collision path of the gas molecules' mean free path, sufficient gas mixing can still be achieved, compensating for the gas mixing inhomogeneity caused by the absence of an AMPLE intermediate buffer tank. This embodiment further verifies the boundary effectiveness of the process window of this invention, demonstrating that a virtual buffering effect can be achieved across the entire range of 300W–800W RF power and 2 Torr–8 Torr cavity pressure, exhibiting good process window tolerance.

[0035] In this embodiment, the B doping mass fraction of 2.0 wt% and the P doping mass fraction of 2.5 wt% are the lower limits of doping concentration, which proves that the present invention can still achieve excellent thin film performance and virtual buffering effect under low doping concentration conditions, further expanding the scope of application of the present invention.

[0036] Comparative Example

[0037] Comparative Example 1: Existing mainstream TMB / TMP organic source + AMPLE intermediate buffer tank process

[0038] A CXZ PECVD system was used, equipped with a complete AMPLE transfer buffer tank automatic replenishment system. The precursor was TEOS+TMB+TMP, with B=3.2wt% and P=3.8wt%, consistent with the doping in the first embodiment. Reflow annealing was performed at 950℃ for 30 min. Results: Residual carbon in the film was 186 ppm; TEM showed numerous carbon nanopores; interface state Dit=4.8×10⁻⁶. 10 cm -2 ·eV -1 The annual maintenance costs for the AMPLE transfer buffer tank, filter element, and pipeline are high, and the TDDB lifespan is shorter than that of the first embodiment.

[0039] Comparative Example 2: US5672907 Benchmark Conventional Hydride Process Without AMPLE

[0040] An AMAT Centura 5200 PECVD deposition chamber was used, and the AMPLE intermediate buffer tank was removed. The deposition gas source was a conventional hydrocarbon-free gas source of SiH4, B2H6, PH3, and N2O, consistent with the gas source of this invention. The deposition process used the conventional process parameters disclosed in US5672907, without optimization of power and pressure windows, and without virtual buffering effect. Test results: Due to the lack of buffer tank hardware and virtual buffering process compensation, gas mixing was severely uneven, the thickness deviation of the film upstream and downstream of the deposition chamber was >12%, the step coverage collapse was obvious, and the film layer was loose and porous, failing to meet the mass production yield requirements; although the gas source was free of carbon and had no obvious carbon impurities, the overall performance of the film was completely unqualified, making mass production application impossible.

[0041] Comparative Example 3: Centura 5200 hydride + retention of AMPLE organic source pathway

[0042] The machine is equipped with a hydride gas source and an idle TMB / TMP AMPLE transfer buffer tank. Hardware procurement and maintenance costs still exist, there is no cost reduction benefit, and the idle pipeline is prone to impurities, which affects the purity of the membrane.

[0043] Reference Figure 4 The process flow comparison diagram shows that the AMLE-buffered hydride process of this invention is as follows: substrate front-end completion - Centura 5200 equipment configuration, complete removal of the AMLE transfer buffer tank and the entire liquid source pipeline - limited RF power of 300W~800W, 2Torr~8Torr chamber pressure, hydride gas source deposition - 950℃ / 30min standard N2 reflow annealing - back-end etching / chemical mechanical polishing / metallization, without the need to adjust the back-end process parameters. The comparative example, the 1TMB / TMP + AMLE transfer buffer tank process, requires a CXZ PECVD + AMLE transfer buffer tank + TMB / TMP liquid source branch. After depositing BPSG with TEOS + TMB + TMP organic precursors, reflow annealing and back-end processes are performed. Its drawback is that the film contains a large amount of carbon-encapsulated closed pores, resulting in a lower TDDB lifetime. In Comparative Example 2, although the conventional hydride AMPLE process does not use carbon as a gas source, it cannot be mass-produced due to uneven gas mixing, large film thickness deviation, step collapse, and loose film layer.

[0044] Reference Figure 5 The bar charts compare the TDDB lifespan and annual hardware maintenance costs. Process 1, Process 2, and Process 3 correspond to Comparative Example 1, Comparative Example 2, and Example 1, respectively. This invention completely eliminates the AMPLE transfer buffer tank hardware, while increasing the TDDB lifespan by 35% compared to the traditional organic source belt AMPLE solution, and reducing the annual AMPLE hardware maintenance cost to zero.

[0045] The performance comparison is shown in the table below:

[0046] Residual carbon content after reflow annealing 186 ppm ≤10ppm 6 ppm Number of carbon-encapsulated micropores in the membrane Numerous visible none none <![CDATA[interface state Dit (cm⁻ 2 ·eV⁻ 1 )]]> <![CDATA[4.8×10 10 ]]> Thin film defects are too large to be detected. <![CDATA[1.2×10 10 ]]> TDDB Average Lifetime Benchmark 100% Unable to meet standards, not suitable for mass production 135% Annual AMPLE hardware maintenance costs high 0 0 Stepped reflow annealing planarization effect qualified Substandard, severely collapsed Pass (better than the benchmark) Gas mixing uniformity Good (depends on physical buffers) Extremely poor (no buffer, no process compensation) Excellent (process virtual buffer compensation)

[0047] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing BPSG thin films without an AMPLE transfer buffer tank based on an AMAT Centura 5200 PECVD device, characterized in that, Includes the following steps: S1. Provide a semiconductor substrate and send the substrate into a Centura 5200 parallel plate plasma deposition chamber. Deposit a BPSG thin film using SiH4, B2H6, PH3, and N2O vapor phase precursors. Control the mass percentage of B and P doping inside the film to be completely consistent with the doping parameters of the reference BPSG thin film prepared using a TMB / TMP organic source and a matching AMPLE transfer buffer tank automatic replenishment system. S2. Perform reflow annealing on the deposited BPSG film: under nitrogen protection atmosphere, annealing temperature 950℃, constant temperature holding for 30 min; S3. After reflow annealing, proceed directly to subsequent etching, chemical mechanical polishing or metallization processes. The entire process does not involve configuring or using a dedicated TMB / TMP AMPLE transfer buffer tank or a matching automatic liquid replenishment and vaporization supply system; The AMPLE transfer buffer tank is an integrated transfer tank specifically designed for storing and transporting liquid TMB / TMP, integrating liquid level sensing, automatic liquid replenishment, constant temperature heating, and gas phase delivery valve assembly. After reflow annealing, the residual carbon impurities of the hydride source BPSG film are ≤10ppm, and there are no carbon-encapsulated micropores in the film. The film interface leakage and dielectric breakdown reliability after time are better than the TMB / TMP organic source BPSG film with the same doping amount and equipped with AMPLE transfer buffer. The deposition chamber employs a customized power-pressure process window, which creates a virtual buffer effect through a high-density plasma environment. This compensates for the uneven gas mixing caused by the absence of an AMPLE transfer buffer tank, ensuring the uniformity and density of the thin film deposition.

2. The method for preparing BPSG thin films using the AMAT Centura 5200 PECVD equipment without an AMPLE transfer buffer tank according to claim 1, characterized in that, The deposition process parameters for the Centura 5200 deposition chamber are as follows: RF power 300W~800W, chamber pressure 2Torr~8Torr; SiH4 flow rate 50sccm~200sccm, B2H6 dilution gas flow rate 10sccm~50sccm, PH3 dilution gas flow rate 15sccm~60sccm, and N2O flow rate 500sccm~2000sccm.

3. The method for preparing BPSG thin films using the AMAT Centura 5200 PECVD equipment without an AMPLE transfer buffer tank according to claim 1, characterized in that, In the reflux annealing process: N2 carrier gas flow rate 5 slm~20 slm, heating rate 5℃ / min~10℃ / min, cooling rate 3℃ / min~8℃ / min.

4. The method for preparing BPSG thin films without an AMPLE transfer buffer tank based on the AMAT Centura 5200 PECVD equipment according to claim 1, characterized in that, The BPSG thin film has a boron doping mass fraction of 2.0 wt% to 5.0 wt% and a p doping mass fraction of 2.5 wt% to 6.0 wt%.

5. The method for preparing BPSG thin films without an AMPLE transfer buffer tank based on the AMAT Centura 5200 PECVD equipment according to claim 1, characterized in that, The BPSG thin film is used as the metal front dielectric layer of logic ICs, power devices, or memory chips.

6. The method for preparing BPSG thin films using the AMAT Centura 5200 PECVD equipment without an AMPLE transfer buffer tank according to claim 1, characterized in that, The Centura 5200 deposition chamber has a radio frequency power of 500W and a chamber pressure of 4Torr.

7. The method for preparing BPSG thin films using the AMAT Centura 5200 PECVD equipment without an AMPLE transfer buffer tank according to claim 1, characterized in that, The BPSG thin film has a boron doping mass fraction of 3.2 wt% and a pion doping mass fraction of 3.8 wt%.

8. The method for preparing BPSG thin films using the AMAT Centura 5200 PECVD equipment without an AMPLE transfer buffer tank according to claim 1, characterized in that, Prior to the deposition step, the TMB / TMP liquid source supply branch of the deposition chamber had been dismantled, and the AMPLE transfer buffer tank and its matching automatic liquid replenishment and vaporization supply system had been removed.

9. The method for preparing BPSG thin films using an AMAT Centura 5200 PECVD equipment without an AMPLE transfer buffer tank according to claim 1, characterized in that, The interface state Dit of the BPSG film after reflow annealing at 950℃ for 30 min is ≤1.2×10⁻⁶. 10 cm -2 ·eV -1 .

10. The method for preparing BPSG thin films without an AMPLE transfer buffer tank based on the AMAT Centura 5200 PECVD equipment according to claim 1, characterized in that, The BPSG film has a residual carbon content of 6 ppm after reflow annealing.

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