A method for fabricating a solar cell with an emitter structure with low, high and low doping concentrations

Abstract

The invention relates to a solar cell manufacture method for an emitting electrode structure with low-high-low doping density. The method comprises a first step of manufacturing the surface of a silicon wafer after the felting process is carried out on the silicon wafer to an emitting electrode, a second step of etching the periphery of the silicon wafer obtained in the first step and removing phosphorosilicate glass, a third step of high temperature annealing of the silicon wafer obtained in the second step and a fourth step of carrying out a sedimentation silicon nitride, silk-screen positive and negative electrodes, back aluminum and sintering in sequence on the silicon wafer obtained in the third step. According to the solar cell manufacture method, uniformity of spreading sheet resistance can be effectively improved, microdefect and foreign ion in the silicon wafer are reduced through the high temperature annealing, lifetime of a minority carrier is prolonged, short-circuit current density is enabled to be increased by 0.1-1mA / cm2, open-circuit voltage is increased by 3-10mV, and conversion efficiency is increased by 0.1-0.5 %.

Description

technical field [0001] The invention relates to the technical field of solar cell fabrication, in particular to a solar cell fabrication method with an emitter structure of low, high, and low doping concentrations. Background technique [0002] Among all kinds of solar cells, crystalline silicon cells have always occupied the most important position. In recent years, great achievements and progress have been made in improving efficiency and reducing cost of crystalline silicon solar cells, further enhancing its dominant position in the future photovoltaic industry. [0003] As the core component of the solar cell, the emitter's surface doping concentration will directly affect the conversion efficiency of the solar cell. Solar cells have two requirements for the emitter: 1. The doping concentration should not be too high, and 2. The surface concentration should not be too low. [0004] At present, the emitter made by the conventional diffusion method cannot meet the above ...

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Problems solved by technology

[0004] At present, the emitter made by the conventional diffusion method cannot meet the above two requirements at the same time

Generally, if the doping concentration is not too high, the Auger recombination will be greatly increased, and the minority carriers formed in the emission region are easy to recombine, resulting in a decrease in short-wave response; if the surface concentration is reduced, the junction depth will also become shallower, thin layer The resistance is high, and the resistance of the emitter must increase, thereby increasing the resistance of the current moving to the grid electrode in the emission area, increasing the probability of PN junction burn-through in the subsequent electrode sintering process, and reducing the battery yield.

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