Novel method for manufacturing p-type poly

Abstract

The invention discloses a novel method for manufacturing p-type poly, which comprises the following steps of: providing a substrate, putting the substrate into a reaction cavity, and introducing 30000-40000 sccm of oxygen at the temperature of 500-700 DEG C or introducing 5000-20000 sccm of nitrous oxide gas at the temperature of 200-700 DEG C, so that a tunneling oxide layer Tunnel SiOx with the thickness of 0.1-2 nm grows on the back surface of a battery piece; the preparation method comprises the following steps of: adding nitrogen oxide or nitrous oxide into a substrate, removing oxygen or nitrous oxide at the temperature of between 200 and 700 DEG C, and introducing mixed gas of 3000 to 4000sccm of silane, 100 to 1000sccm of borane and 2000 to 20000sccm of hydrogen, so that a bottom layer Poly with the thickness of between 5 and 100nm grows on the substrate; the preparation method comprises the following steps of: removing mixed gas of silane, borane and hydrogen at the temperature of between 200 and 700 DEG C, introducing oxygen at the temperature of between 30000 and 40000 sccm or nitrous oxide gas at the temperature of between 5000 and 20000 sccm, and generating a silicon oxide (SiOx) multifunctional laminated layer with a certain thickness of between 0.5 and 30 nanometers. According to the method, the original p-type Poly layer is initially prepared in a PECVD mode, and then auxiliary doping is carried out through laser and annealing processes so as to accurately control the effective doping concentration of boron atoms.

Description

Technical Field

[0001] The invention relates to the technical field of solar cell polycrystalline silicon Poly preparation, in particular to a novel method for preparing p-type poly. Background Art

[0002] High-efficiency crystalline silicon solar cells, tunnel oxide passivated contact solar cells (Tunnel Oxide Passivated Contact solar cells, TOPCon Solar Cell) and back contact solar cells (Back Contact Solar Cell, BC Solar Cell), all of the above cells can use high-quality ultra-thin silicon oxide and doped polycrystalline silicon layers to achieve high-efficiency passivation and selective carrier collection on the entire back side of the cell.

[0003] In the process of preparing p-type doped polysilicon using traditional PECVD deposition technology, the concentration of boron atoms is difficult to effectively control. Currently, the LPCVD deposition technology is mainly used to make p-type poly layers. However, LPCVD equipment occupies a large area and consumes a lot of energy, which directly affects production costs and also brings about high carbon emissions. In addition, a large number of quartz devices are used in LPCVD equipment, which are mainly fragile and consumable parts. Their frequent maintenance and replacement leads to long downtime and affects production progress.

[0004] Therefore, a new type of PECVD technology is designed to manufacture the p-type poly layer to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a novel method for preparing p-type poly to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a novel method for preparing p-type poly, comprising the following steps: Step S1: providing a substrate, placing the substrate in a reaction chamber, passing 30000-40000 sccm oxygen gas at 500-700°C or 5000-20000 sccm nitrous oxide gas at 200-700°C, so as to grow a 0.1-2 nm tunnel oxide layer Tunnel SiOx on the back of the cell; Step S2: at a temperature of 200-700° C., remove oxygen or nitrous oxide, and pass a mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane, and 2000-20000 sccm hydrogen to grow a bottom layer Poly of more than 5-100 nm; Step S3: at a temperature of 200-700° C., remove the mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane, and 2000-20000 sccm hydrogen, and pass 30000-40000 sccm oxygen or 5000-20000 sccm nitrous oxide gas to generate silicon oxide SiOx with a certain thickness of 0.5-2.5 nm; Step S4: at a temperature of 200-700° C., remove oxygen or nitrous oxide, and pass a mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane, and 2000-20000 sccm hydrogen to grow a certain thickness of Poly; Step S5: Repeat: Step S3 and step S4 can be performed once or multiple times to obtain the optimal p-type poly layer; Step S6: at a temperature of 200-700° C., remove the mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane and 2000-20000 sccm hydrogen, and introduce 30000-40000 sccm oxygen or 5000-20000 sccm nitrous oxide to form a silicon oxide SiOx multifunctional laminate with a certain thickness of 0.5-30 nm.

[0007] Preferably, the SiOx in the Poly layer in S2 to S6 has 0-n layers.

[0008] Preferably, the bottom tunneling oxide layer and p-type doped polysilicon layer (p-type poly layer) obtained in steps S1 to S6 are subjected to laser-assisted doping and a subsequent annealing process is performed to effectively activate the doped boron atoms and perform high-quality repair of laser damage.

[0009] Preferably, the laser-assisted doping process uses a laser with a power of 1-200W and a wavelength in the range of 300-600nm or 800-1100nm to process the product surface, with a speed of 5000-50000mm / s, a spot size of 50-100μm, and a pulse width of 0.1-200μs.

[0010] Preferably, the annealing to activate doped boron atoms and the laser damage repair process are as follows: at a temperature of 800° C. to 1200° C., a nitrogen flow rate of 1000-20000 sccm is passed, and an annealing process is performed for 30 minutes to 120 minutes according to the effective boron atom doping concentration requirement.

[0011] Preferably, the reaction chamber adopts a furnace tube, and a PECVD deposition process is used in the furnace tube to deposit and form an effective p-type doped polysilicon layer.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The original p-type Poly layer is initially prepared using the PECVD method, and then auxiliary doping is performed through laser and annealing processes to achieve precise control of the effective doping concentration of boron atoms.

[0013] PECVD has the characteristic of high output per unit time, so the factory area required for GW-level solar cell preparation is significantly lower than that of LPCVD, which is conducive to the upgrading of existing factories and production lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0016] See also Figure 1 The present invention provides a technical solution: a novel method for preparing p-type poly, comprising the following steps: Step S1: providing a substrate, placing the substrate in a reaction chamber, passing 30000-40000 sccm of oxygen at a temperature of 500-700°C, so as to grow a 0.1-2 nm tunnel oxide layer Tunnel SiOx on the back of the cell; Step S2: at a temperature of 200-700° C., remove oxygen and pass a mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane and 2000-20000 sccm hydrogen to grow a bottom layer Poly of more than 5-100 nm; Step S3: at a temperature of 200-700° C., remove the mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane, and 2000-20000 sccm hydrogen, and pass 30000-40000 sccm oxygen to generate silicon oxide SiOx with a certain thickness of 0.5-2.5 nm; Step S4: at a temperature of 200-700° C., remove oxygen and pass a mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane and 2000-20000 sccm hydrogen to grow a Poly with a certain thickness; Step S5: Repeat: Step S3 and step S4 can be performed once or multiple times to obtain the optimal p-type poly layer; Step S6: at a temperature of 200-700° C., remove the mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane and 2000-20000 sccm hydrogen, and introduce 30000-40000 sccm oxygen to generate a silicon oxide SiOx multifunctional laminate with a certain thickness of 0.5-30 nm. Example

[0017] See also Figure 1 The present invention provides a technical solution: a novel method for preparing p-type poly, comprising the following steps: Step S1: providing a substrate, placing the substrate in a reaction chamber, passing 5000-20000 sccm of nitrous oxide gas at a temperature of 200-700° C., so as to grow a 0.1-2 nm tunnel oxide layer Tunnel SiOx on the back of the cell; Step S2: at a temperature of 200-700° C., remove the nitrous oxide and pass a mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane and 2000-20000 sccm hydrogen to grow a bottom layer Poly of more than 5-100 nm; Step S3: at a temperature of 200-700° C., remove the mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane, and 2000-20000 sccm hydrogen, and pass 5000-20000 sccm nitrous oxide gas to generate silicon oxide SiOx with a certain thickness of 0.5-2.5 nm; Step S4: at a temperature of 200-700° C., remove the nitrous oxide and pass a mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane and 2000-20000 sccm hydrogen to grow a Poly with a certain thickness; Step S5: Repeat: Step S3 and step S4 can be performed once or multiple times to obtain the optimal p-type poly layer; Step S6: At a temperature of 200-700° C., remove the mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane, and 2000-20000 sccm hydrogen, and pass 5000-20000 sccm nitrous oxide gas to generate a SiOx silicon oxide SiOx multifunctional stack with a certain thickness of 0.5-30 nm.

[0018] In the present invention, the SiOx in the Poly layer has 0-n layers.

[0019] In the present invention, the bottom tunneling oxide layer and the p-type doped polysilicon layer obtained in step S1, step S2, step S3, step S4, step S5 and step S6 are subjected to laser-assisted doping and a subsequent annealing process is performed to effectively activate the doped boron atoms and perform high-quality repair of laser damage, thereby optimizing the effective doping concentration in the p-type poly, increasing the initial boron doping concentration prepared by PECVD with laser assistance, and solving the technical difficulties in preparing the p-type poly layer using the traditional PECVD technology.

[0020] In the present invention, the laser-assisted doping process uses a laser with a power of 1-200w and a wavelength in the range of 300-600nm or 800-1100nm to process the product surface, with a speed of 5000-50000mm / s, a spot size of 50-100μm, and a pulse width of 0.1-200μs.

[0021] In the present invention, the annealing to activate doped boron atoms and the laser damage repair process are as follows: at a temperature of 800°C-1200°C, a nitrogen flow rate of 1000-20000sccm is passed, and an annealing process of 30mins-120mins is performed according to the effective boron atom doping concentration requirement. The purpose of the annealing process is to activate doped boron atoms and complete laser damage repair.

[0022] In the present invention, the reaction chamber adopts a furnace tube, and the polysilicon is deposited in the furnace tube using a PECVD deposition process.

[0023] In the present invention, the deposition temperature is 200-700°C.

[0024] The present invention: PECVD deposits initial p-type doped polysilicon. Under the current circumstances, the traditional PECVD is used to prepare the p-type polysilicon structure, and the polysilicon layer has only one layer. The concentration of boron atoms is not easy to control under high-temperature diffusion, which is not convenient for amplifying the advantages of this technology. Therefore, during the growth process of the Poly layer, the present invention adopts a method of passing a specific gas to grow 0-n layers of SiOx in the Poly layer. The grown SiOx layer can be used as a barrier layer, a mask or a secondary tunneling layer according to the needs of process optimization, and can also play a role of intermediate passivation.

[0025] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field. Although the embodiments of the present invention have been shown and described, it is understood by ordinary technicians in the field that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A novel method for making p-type poly, characterized in that: The steps include: Step S1: providing a substrate, placing the substrate in a reaction chamber, passing 30000-40000 sccm of oxygen gas at 500-700°C or passing 5000-20000 sccm of nitrous oxide gas at 200-700°C, so as to grow a 0.1-2 nm tunnel oxide layer Tunnel SiOx on the back of the cell; Step S2: at a temperature of 200-600° C., remove oxygen or nitrous oxide, and pass a mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane, and 2000-20000 sccm hydrogen to grow a bottom layer Poly of more than 5-100 nm; Step S3: at a temperature of 200-700° C., remove the mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane, and 2000-20000 sccm hydrogen, and pass 30000-40000 sccm oxygen or 5000-20000 sccm nitrous oxide gas to generate silicon oxide SiOx with a certain thickness of 0.5-2.5 nm; Step S4: at a temperature of 200-700° C., remove oxygen or nitrous oxide, and pass a mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane, and 2000-20000 sccm hydrogen to grow a certain thickness of Poly; Step S5: Repeat: Step S3 and step S4 can be performed once or multiple times to obtain the optimal p-type poly layer; Step S6: at a temperature of 200-700° C., remove the mixed gas of 3000-4000 sccm silane, 100-1000 sccm borane and 2000-20000 sccm hydrogen, and introduce 30000-40000 sccm oxygen or 5000-20000 sccm nitrous oxide to form a silicon oxide SiOx multifunctional laminate with a certain thickness of 0.5-30 nm.

2. A novel method for preparing p-type poly according to claim 1, characterized in that: The SiOx in the Poly layer in the steps S2, S3, S4, S5 and S6 has 0-n layers.

3. A novel method for preparing p-type poly according to claim 1, characterized in that: The bottom tunneling oxide layer and p-type doped polysilicon layer obtained in step S1, step S2, step S3, step S4, step S5 and step S6 are subjected to laser-assisted doping and a subsequent annealing process is performed to effectively activate the doped boron atoms and perform high-quality repair of laser damage.

4. A novel method for preparing p-type poly according to claim 3, characterized in that: The laser-assisted doping process uses a laser with a power of 1-200W and a wavelength in the range of 300-600nm or 800-1100nm to process the surface of the product, with a speed of 5000-50000mm / s, a spot size of 50-100μm, and a pulse width of 0.1-200μs.

5. A novel method for preparing p-type poly according to claim 3, characterized in that: The annealing process for activating doped boron atoms and repairing laser damage is as follows: at a temperature of 800° C. to 1200° C., a nitrogen flow rate of 1000 to 20000 sccm is passed, and an annealing process is performed for 30 minutes to 120 minutes according to the effective boron atom doping concentration requirement.

6. A novel method for preparing p-type poly according to claim 1, characterized in that: The reaction chamber adopts a furnace tube, and a PECVD deposition process is adopted in the furnace tube to deposit and form polysilicon.

7. A novel method for preparing p-type poly according to claim 6, characterized in that: The deposition temperature is 200-700°C.

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