NOVELTY - A variable temperature phosphorus and aluminum in silicon sheet gettering method for solar cells involves removing damaged layer by heating sodium hydroxide solution in water bath, and adding a substrate silicon sheet into the solution. The silicon sheet is cleaned with acetone solution and anhydrous ethanol, and dried with nitrogen. The silicon sheet is spin-coated with phosphorus and placed in a vacuum coating machine. The silicon sheet is gettered, cooled and placed in hydrofluoric acid and nitric acid for 40-70 seconds for removing corrosion volume of gettering layer.    USE - Method for gettering phosphorus and aluminum in silicon sheet for solar cells at variable temperature.    ADVANTAGE - The method enables gettering phosphorus and aluminum in silicon sheet simply with effective control of temperature for absorbing aluminum and phosphorus impurities completely, avoids need of other devices, has obvious gettering effect in easy way, improved life time of silicon sheet, and reduces process cycle by satisfying the gettering effect.    DETAILED DESCRIPTION - A variable temperature phosphorus and aluminum in silicon sheet gettering method for solar cells involves removing damaged layer by preparing concentration of 10-15 wt.% sodium hydroxide solution, heating the sodium hydroxide solution in water bath at constant temperature of 80 degrees C, adding a substrate silicon sheet into the solution for 8-15 minutes to remove a damaged layer caused by sawing from the silicon sheet and washing the silicon sheet with deionized water for 3 minutes. Silicon sheet is cleaned with acetone solution ultrasonically at 25 degrees C for 5 minutes to remove damaged layer from the silicon sheet, and washed with deionized water for 3 minutes. Silicon sheet is cleaned with anhydrous ethanol ultrasonically at 25 degrees C for 5 minutes, washed with deionized water for 3 minutes, and dried with nitrogen. Silicon sheet is spin-coated with phosphorus for 20-30 seconds by absorbing phosphorus on both sides of silicon sheet to thickness of 1-2 microns at rotating speed of 1500-2200 revolutions/minute. Coated silicon sheet is dried at 100-150 degrees C for 10-15 minutes with heat-treatment furnace. Coated silicon sheet is placed in vacuum coating machine at 620-700 degrees C for evaporating aluminum film with thickness of 0.5-2 microns on both sides of silicon sheet. Gettering of silicon sheet is performed by placing vapor deposited silicon sheet in furnace for heat treatment at 850-950 degrees C for 25-65 minutes under nitrogen atmosphere protection. Second gettering of silicon sheet is performed by heat-treating the silicon sheet at 700-800 degrees C for 40-80 minutes under nitrogen atmosphere protection. Gettered silicon sheet is cooled to room temperature and placed in 49 wt.% hydrofluoric acid and 65 wt.% nitric acid for 40-70 seconds for removing corrosion volume of gettering layer. Volume ratio of the hydrofluoric acid and nitric acid is 1:2-4.