A method for boron (b) diffusion doping

A diffusion furnace and substrate technology, which is applied in the field of high temperature liquid BBr3 boron diffusion preparation, can solve the problems of difficulty in achieving uniform distribution of diffusion tubes, non-uniformity obstacles, etc., and achieve the effects of improving device performance, reducing high temperature effects and facilitating operation.

CN102797040BInactive Publication Date: 2015-08-12INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2015-08-12
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a method for diffusion doping of boron (B). The method comprises the following steps of 1, carrying out corrosion washing of the surface of a substrate needing doping, and then drying the substrate, 2, heating a diffusion furnace and simultaneously, filling pure nitrogen into a diffusion quartz tube, putting the clean substrate treated by the step 1 into a diffusion quartz tube thermostatic zone when a temperature is in a range of 850 to 1050 DEG C, sealing a furnace mouth of the diffusion furnace, and filling oxygen, nitrogen carrying a B source and vaporous water into the diffusion quartz tube after a temperature of the diffusion furnace is stable, wherein a pure nitrogen flow is in a range of 12 to 20slm / min; an oxygen flow is in a range of 2000 to 5000sccm / min; a flow of the nitrogen carrying a B source is in a range of 800 to 3000sccm / min; and a vaporous water flow is in a range of 100 to 900sccm / min, and 3, taking out the treated substrate after diffusion is finished, and cooling.
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Description

technical field

[0001] The invention relates to a high-temperature liquid BBr in a crystalline silicon solar cell 3 Boron diffusion preparation method. Background technique

[0002] Boron diffusion doping is the key to achieving high conversion efficiency in solar cells (Martin A. Green, Andrew W. Blkers, Jianhua Zhao, Adele M. Milne, Aihua Wang, Ximing Dai, "Characterization of 23-percent efficient silicon solar cells ".IEEE Transactions on Electron Devices.Vol.37,331-336; Jianhua Zhao, Aihua Wang, Martin A.Green, 24.5% efficiency PERT silicon solar cells on SHE MCZ substrates and cell performance on other SHE CZ and FZ substrates, Solar Energy Materials &Solar Cells,66(2001)27-36), its difficulty lies in boron oxide (B 2 o 3 ) has a boiling point of 1860°C (Yaw's thermophysical properties of chemicals and hydrolarbous), and is in a liquid state at a general diffusion temperature. During the diffusion process, the deposition on the surface of the silicon wafer is uneven,...

Examples

Embodiment 1

[0036] 1. Set the substrate to 125×125 mm 2 The N-type crystalline silicon is prepared by alkali etching, RCA cleaning and nitrogen blow-drying for later use.

[0037] 2. Introduce 12 slm of large nitrogen into the diffusion quartz tube, and after the temperature rises to 900°C, slowly push the quartz boat loaded with the substrate into the constant temperature zone of the diffusion quartz tube. After the substrate is in place, seal the mouth of the diffusion furnace.

[0038] 3. After the temperature is stabilized at 900°C, introduce large nitrogen 12slm, oxygen 2000sccm, source-carrying small nitrogen 1500sccm, and gaseous water 100sccm into the diffusion quartz tube at the same time, and the boron diffusion process takes about 1h.

[0039] 4. After the diffusion is completed, slowly pull out the quartz boat loaded with the substrate from the diffusion quartz tube, and take out the substrate silicon wafer when the temperature of the substrate reaches room temperature. It ...

Embodiment 2

[0042] 1. Set the substrate to 125×125 mm 2 N-type crystalline silicon, alkali-etched for texturing, RCA cleaning and nitrogen blow-drying for later use.

[0043] 2. Introduce 12 slm of large nitrogen into the diffusion quartz tube. After the temperature rises to 900°C, slowly push the quartz boat loaded with silicon wafers into the constant temperature zone of the diffusion quartz tube. After the wafer is in place, seal the mouth of the diffusion furnace.

[0044] 3. After the temperature is stabilized at 900°C, introduce large nitrogen 12slm, oxygen 2000sccm, source-carrying small nitrogen 1500sccm, and gaseous water 150sccm into the diffusion quartz tube at the same time, and the boron diffusion process takes about 1h.

[0045] 4. Slowly pull out the quartz boat loaded with silicon wafers from the diffusion quartz tube after the diffusion is completed, and take out the substrate silicon wafers when the temperature of the silicon wafers reaches room temperature phase. The...

Embodiment 3

[0048] 1. Set the substrate to 125×125 mm 2 The N-type crystalline silicon is subjected to alkali etching for texturing, RCA cleaning and nitrogen blow-drying before use.

[0049] 2. Introduce 12 slm of large nitrogen into the diffusion quartz tube. After the temperature rises to 950°C, slowly push the quartz boat loaded with silicon wafers into the constant temperature zone of the diffusion quartz tube. After the wafer is in place, seal the mouth of the diffusion furnace.

[0050] 3. After the temperature is stabilized at 950°C, introduce large nitrogen 12slm, oxygen 2000sccm, source-carrying small nitrogen 1500sccm, and gaseous water 900sccm into the diffusion quartz tube at the same time, and the boron diffusion process takes about 1h.

[0051] 4. After the diffusion is completed, slowly pull out the quartz boat loaded with silicon wafers from the diffusion quartz tube, and take out the silicon wafers when the temperature of the silicon wafers reaches room temperature. T...