Low-voltage Diffusion Process for Crystalline Silicon Cells

A technology of crystalline silicon battery and diffusion process, which is applied in the field of diffusion process, can solve the problems that it is difficult to improve the uniformity of the longitudinal concentration distribution of inter-chip diffusion doping, reduce the service life of vacuum pumps, and restrict the uniformity of silicon wafer doping, etc., to achieve improved Consistency of longitudinal doping concentration distribution, improvement of contact probability, and improvement of the uniformity of inter-chip diffusion resistance

CN105261670BActive Publication Date: 2017-06-16HUNAN RED SUN PHOTOELECTRICITY SCI & TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2017-06-16

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Abstract

The invention discloses a low-pressure diffusion technology for a crystalline silicon cell. The technology comprises the following steps: (1) a high-temperature oxidation before diffusion; (2) a low-pressure diffusion, namely preparing a PN knot by a sub-step diffusion method; and (3) annealing, namely changing internal pressure to remove impurities. According to the low-pressure diffusion technology, the uniformity between diffusion sheets can be improved; the temperature of a temperature zone in a fire hole is lowered, namely the temperature uniformity of various temperature zones of a diffusion tube is improved; the problem of a great fluctuation of sheet resistance of the fire hole of a diffusion furnace is solved; the service lifetime of a vacuum pump is prolonged; and the production cost of a diffusion procedure is reduced.
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Description

technical field

[0001] The invention belongs to the field of diffusion processing in the preparation process of crystalline silicon batteries, and in particular relates to a diffusion process capable of improving the uniformity between diffusion sheets of a low-voltage diffusion furnace and the stability of battery performance. Background technique

[0002] In terms of the industrialization of crystalline silicon cells, high-temperature diffusion methods are usually used to prepare PN junctions, and the industrial preparation of high-resistance emitters with good inter-chip and intra-chip uniformity is an important way to improve battery conversion efficiency and electrical performance stability. The optimization space of the diffusion process can be improved as a whole, and the number of battery efficiency bins can be reduced. With the continuous development of high square resistance paste, improving the square resistance value of the emitter, the consistency of the longitu...

Examples

Embodiment 1

[0037] A low-pressure diffusion process of the present invention comprises the following steps:

[0038] (1) High-temperature oxidation before diffusion: After the furnace mouth is closed, pump air to the set low pressure and oxidize at high temperature, and pre-grow nano-scale thickness SiO on the surface of the silicon wafer 2 ;

[0039] The specific four-step process steps are shown in Table 3:

[0040] Table 3: Process parameters of the first four steps of diffusion

[0041]

[0042] (2) Low-pressure diffusion: the step-by-step diffusion method is adopted to reduce the temperature difference in each temperature zone, improve the uniformity of diffusion resistance value between sheets and the consistency of vertical doping concentration distribution, reduce the production cost of the diffusion process and reduce the performance requirements of vacuum pumps. Purpose.

[0043] The specific diffusion steps are as follows:

[0044] The first step is low-pressure pre-diff...