Oxidation annealing technology for improving conversion efficiency of crystalline silicon solar cell

The invention discloses an oxidation annealing technology for improving the conversion efficiency of a crystalline silicon solar cell. The technology comprises the following steps: raising the temperature of the oxidation process to 680-760 DEG C, and simultaneously introducing 5000-10000 sccm of nitrogen and 500-1000 sccm of oxygen for 300-600 s; reducing the temperature of the cooling oxidation process to 650-700 DEG C, and introducing 20000-30000 sccm of nitrogen and 3000-6000 sccm of oxygen at the same time for 600-1000 s; stepwise reducing the first annealing process temperature to 600-650 DEG C, and introducing 20000-30000 sccm of nitrogen in at the same time, and the time is 1200-2000s; and stepwise reducing the second annealing process temperature to 550-600 DEG C, and introducing 20000-30000 sccm of nitrogen for 1200-1800 s. The conversion efficiency gain of the crystalline silicon solar cell can be realized, the internal defects of the silicon wafer can be further made up by the newly added heating