阅读说明：本技术 一种原位掺杂非晶硅的晶化退火处理方法 (Crystallization annealing treatment method for in-situ doped amorphous silicon ) 是由 许佳平 张文超 王文科 曹育红 任常瑞 王敏 符黎明 于 2021-07-23 设计创作，主要内容包括：本发明公开了一种原位掺杂非晶硅的晶化退火处理方法,采用链式热处理炉对沉积有原位掺杂非晶硅的硅片进行晶化退火处理。本发明能省去在晶化退火处理和湿法清洗处理之间的下料和上料环节,避免在这些环节中出现碎片、不良的问题；本发明还能能减少晶化退火处理所需要的工艺时间；本发明还使用光线对硅片进行加热,由于有了光子的辅助,杂质元素更容易占据到硅材料晶格的替代位上,实现掺杂元素激活率的提高。(The invention discloses a crystallization annealing treatment method of in-situ doped amorphous silicon, which adopts a chain type heat treatment furnace to perform crystallization annealing treatment on a silicon wafer deposited with the in-situ doped amorphous silicon. The invention can save the blanking and feeding ring section between the crystallization annealing treatment and the wet cleaning treatment, and avoid the problems of fragments and badness in the links; the invention can also reduce the process time required by crystallization annealing treatment; the invention also uses light to heat the silicon chip, and the impurity elements can easily occupy the substitution positions of the silicon material crystal lattice due to the assistance of photons, thereby realizing the improvement of the activation rate of the doping elements.)

1. A crystallization annealing treatment method for in-situ doped amorphous silicon is characterized in that a chained heat treatment furnace is adopted to carry out crystallization annealing treatment on a silicon wafer deposited with the in-situ doped amorphous silicon.

2. The method as claimed in claim 1, wherein a temperature-raising zone, an annealing zone and a cooling zone are provided in the thermal processing furnace, the silicon wafer is transported by the transportation mechanism sequentially through the temperature-raising zone, the annealing zone and the cooling zone, the temperature of the silicon wafer is raised to a target process temperature in the temperature-raising zone, the silicon wafer deposited with the in-situ doped amorphous silicon is subjected to the crystallization annealing treatment in the annealing zone, and the silicon wafer subjected to the crystallization annealing treatment is cooled in the cooling zone.

3. The in-situ doped amorphous silicon crystallization annealing processing method according to claim 2, wherein the conveying mechanism comprises a roller and/or a conveyor belt.

4. The method as claimed in claim 2, wherein the in-situ doped amorphous silicon is crystallized and annealed by heating the silicon wafer with the in-situ doped amorphous silicon deposited therein by light irradiation.

5. The in-situ doped amorphous silicon crystallization annealing treatment method as claimed in claim 4, wherein the light with the wavelength of 600-4000 nm is used for illumination heating.

6. The method as claimed in claim 2, wherein the annealing zone comprises a plurality of temperature zones sequentially arranged along the silicon wafer conveying direction.

7. The in-situ doped amorphous silicon crystallization annealing treatment method as claimed in claim 6, wherein the annealing zone comprises six temperature zones sequentially arranged along the silicon wafer conveying direction: the temperature control system comprises a first temperature zone with the temperature of 500-650 ℃, a second temperature zone with the temperature of 600-800 ℃, a third temperature zone with the temperature of 750-900 ℃, a fourth temperature zone with the temperature of 850-1050 ℃, a fifth temperature zone with the temperature of 850-650 ℃ and a sixth temperature zone with the temperature of 650-300 ℃.

8. The method as claimed in claim 2, wherein nitrogen or a mixture of nitrogen and oxygen is introduced into the annealing zone.

9. The in-situ doped amorphous silicon crystallization annealing treatment method as claimed in claim 2, wherein the transmission speed of the silicon wafer is 1.5-6 m/min, and the total time of the silicon wafer passing through the annealing interval is 1.5-12 min.

10. The method as claimed in claim 2, wherein the silicon wafer after the crystallization annealing is cooled by air cooling in the cooling zone.

11. The in-situ doped amorphous silicon crystallization annealing treatment method as claimed in claim 1, wherein the output end of the chained heat treatment furnace is connected to chained wet cleaning equipment, the silicon wafer output from the chained heat treatment furnace is directly input into the chained wet cleaning equipment, and the silicon wafer is subjected to wet cleaning treatment in the chained wet cleaning equipment.

Technical Field

The invention relates to the technical field of photovoltaics, in particular to a crystallization annealing treatment method for in-situ doped amorphous silicon.

Background

TOPCon is considered to be the most promising high-efficiency crystalline silicon solar cell technology for next-generation mass production after PERC cells. In the fabrication process of the TOPCon cell, in one of the technical routes, in-situ doped amorphous silicon is used, and high-temperature crystallization activation annealing needs to be performed on the in-situ doped amorphous silicon.

The existing high-temperature crystallization annealing mode is carried out in batches in a tube furnace. And loading the silicon wafer deposited with the in-situ doped amorphous silicon into a quartz boat through an automatic wafer inserting and unloading device, and then feeding the quartz boat into the tube furnace. After the quartz boat with silicon wafers is fed into the tube furnace, the furnace door is closed, and the temperature is raised to the designated process temperature by heating with the resistance wires. And then annealing for 10-60 minutes, cooling, opening the furnace door after the temperature of the silicon wafer is reduced to a specified temperature, taking out the quartz boat with the silicon wafer, and taking down the silicon wafer by using an automatic wafer loading and unloading device. And when the subsequent chain wet cleaning process is achieved, the materials need to be fed again.

From the above, in the conventional tube annealing crystallization activation mode, the silicon wafer needs to be loaded on the quartz boat by the automatic wafer inserting and unloading device, and the silicon wafer is unloaded from the quartz boat after the process is completed. And feeding again in the subsequent chain wet cleaning process. In the automatic insertion and unloading process, a certain proportion of fragments and defects are inevitable. After the quartz boat with the silicon wafers is fed into the furnace tube, a resistance wire heating temperature rise process is carried out, and a section of temperature reduction process is carried out after annealing is finished, so that the time of the whole process is longer, and is about 90 min. In addition, the annealing is carried out by using a resistance wire heating mode, the physical process is mainly a thermal process, the doping elements cannot completely occupy the substitution sites of the silicon material crystal lattice, and the activation rate of the electrical activity is limited.

Disclosure of Invention

The invention aims to provide a crystallization annealing treatment method for in-situ doped amorphous silicon, which adopts a chain type heat treatment furnace to perform crystallization annealing treatment on a silicon wafer deposited with the in-situ doped amorphous silicon.

Preferably, a heating interval, an annealing interval and a cooling interval are arranged in the chain type heat treatment furnace, the silicon wafer is conveyed by the conveying mechanism to sequentially pass through the heating interval, the annealing interval and the cooling interval, the temperature of the silicon wafer is raised to the target process temperature in the heating interval, the silicon wafer deposited with in-situ doped amorphous silicon is subjected to crystallization annealing treatment in the annealing interval, and the silicon wafer subjected to crystallization annealing treatment is subjected to cooling treatment in the cooling interval.

Preferably, the conveying mechanism comprises rollers and/or a conveyor belt.

Preferably, in the annealing zone, the silicon wafer deposited with the in-situ doped amorphous silicon is subjected to crystallization annealing treatment by illumination heating.

Preferably, light with the wavelength of 600-4000 nm is used for illumination heating.

Preferably, the annealing zone comprises a plurality of temperature zones sequentially arranged along the conveying direction of the silicon wafer, and each temperature zone can be further subdivided into at least two small temperature zones.

Preferably, the annealing zone comprises six temperature zones sequentially arranged along the conveying direction of the silicon wafer: the temperature control system comprises a first temperature zone with the temperature of 500-650 ℃, a second temperature zone with the temperature of 600-800 ℃, a third temperature zone with the temperature of 750-900 ℃, a fourth temperature zone with the temperature of 850-1050 ℃, a fifth temperature zone with the temperature of 850-650 ℃ and a sixth temperature zone with the temperature of 650-300 ℃.

Preferably, nitrogen or a mixed gas of nitrogen and oxygen is introduced into the annealing zone.

Preferably, the transmission speed of the silicon wafer is 1.5-6 m/min, and the total time of the silicon wafer passing through the annealing interval is 1.5-12 min.

Preferably, the silicon wafer subjected to the crystallization annealing is cooled by air cooling in the cooling zone.

Preferably, the output end of the chain type heat treatment furnace is connected with chain type wet cleaning equipment, the silicon wafer output by the chain type heat treatment furnace is directly input into the chain type wet cleaning equipment, and the silicon wafer is subjected to wet cleaning treatment in the chain type wet cleaning equipment.

The invention has the advantages and beneficial effects that:

the output end of the chained heat treatment furnace can be directly butted with chained wet cleaning equipment, and the chained silicon wafer conveying mode is adopted, so that the silicon wafers output by the chained heat treatment furnace can be directly conveyed to the chained wet cleaning equipment, the blanking and feeding ring sections between the crystallization annealing treatment and the wet cleaning treatment are omitted, and the problems of fragments and defects in the steps are avoided.

In the annealing interval, the silicon wafer deposited with the in-situ doped amorphous silicon is subjected to crystallization annealing treatment by illumination heating, and the illumination heating adopts light with the wavelength of 600-4000 nm, so that the silicon wafer can sufficiently absorb the energy of the light, the temperature required by annealing can be increased from room temperature within a short time (0.1-2 min), and the process time required by the silicon wafer to pass through a chain type heat treatment furnace can be reduced.

The invention uses a chain type silicon chip transmission mode, and silicon chips are spaced at a certain distance; in the cooling interval, the silicon wafer after the crystallization annealing treatment is cooled by air cooling, so that the temperature of the silicon wafer can be reduced to room temperature in a short time, and the process time required by the silicon wafer to pass through the chain type heat treatment furnace can be further reduced.

More importantly, the invention heats the silicon wafer by using light, and the impurity elements are easier to occupy the substitution positions of the silicon material crystal lattice due to the assistance of photons, thereby realizing the improvement of the activation rate of the doping elements.

Detailed Description

The following further describes embodiments of the present invention with reference to examples. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

The invention provides a crystallization annealing treatment method of in-situ doped amorphous silicon, which adopts a chain type heat treatment furnace to carry out crystallization annealing treatment on a silicon wafer deposited with the in-situ doped amorphous silicon; and the output end of the chain type heat treatment furnace is connected with the input end of the chain type wet cleaning equipment, the silicon wafer output by the chain type heat treatment furnace is directly input into the chain type wet cleaning equipment, and the silicon wafer is subjected to wet cleaning treatment in the chain type wet cleaning equipment.

Specifically, the method comprises the following steps:

setting a heating interval, an annealing interval and a cooling interval in a chain type heat treatment furnace, wherein the silicon wafer is conveyed by a conveying mechanism to pass through the heating interval, the annealing interval and the cooling interval in sequence; the conveying mechanism comprises a roller and/or a conveyor belt; the transmission speed of the silicon wafer is 1.5-6 m/min;

1) in the temperature rise interval:

raising the temperature of the silicon wafer to a target process temperature;

2) in the annealing interval:

introducing nitrogen or mixed gas of nitrogen and oxygen, and carrying out crystallization annealing treatment on the silicon wafer deposited with the in-situ doped amorphous silicon through illumination heating; light with the wavelength of 600-4000 nm is adopted for illumination heating;

the annealing interval comprises six temperature zones which are sequentially arranged along the conveying direction of the silicon wafer: the temperature control system comprises a first temperature zone with the temperature of 500-650 ℃, a second temperature zone with the temperature of 600-800 ℃, a third temperature zone with the temperature of 750-900 ℃, a fourth temperature zone with the temperature of 850-1050 ℃, a fifth temperature zone with the temperature of 850-650 ℃ and a sixth temperature zone with the temperature of 650-300 ℃; if necessary, each temperature zone can be further refined and divided into at least two small temperature zones;

the total time of the silicon wafer passing through the annealing interval is 1.5-12 min;

3) in the cooling zone:

and cooling the silicon wafer subjected to crystallization annealing treatment by air cooling.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.