NOVELTY - Diffusing crystalline silicon wafer, comprises cleaning and etching silicon crystal using hydrofluoric acid or nitric acid on a surface of crystalline silicon wafers, where the silicon crystal is placed in a vertical diffusion furnace for diffusion process after cleaning and etching, placing the cleaned and etched silicon crystal on a quartz boat, and then filling with rock crystal silicon at a speed of 1 plus minus 300 mm/minute, where the furnace comprises a cavity and a chamber having an initial temperature of 0.5 plus minus 800 degrees C.    USE - The method is useful for diffusing crystalline silicon wafer that is useful in a solar cell (claimed).    ADVANTAGE - The method is capable of simply and economically diffusing the crystalline silicon wafer thus improving the uniformity of molecular and crystal silicon chip.    DETAILED DESCRIPTION - Diffusing crystalline silicon wafer comprises cleaning and etching silicon crystal using hydrofluoric acid or nitric acid on a surface of crystalline silicon wafers, where the silicon crystal is placed in a vertical diffusion furnace for diffusion process after cleaning and etching, placing the cleaned and etched silicon crystal on a quartz boat, then filling with rock crystal silicon at a speed of 1 plus minus 300 mm/minute, where the furnace comprises a cavity and a chamber having an initial temperature of 0.5 plus minus 800 degrees C and inside and outside of the furnace is surrounded with nitrogen gas having a flow rate of plus minus 0.05 l/minute, stopping the flow of nitrogen gas in the cavity of the furnace to an internal and external oven via a vacuum pump for 5-10 minutes, then maintaining a pressure of the furnace at 50 plus minus 300 mTorr, vacuuming the internal and external oven for 3-5 minutes to ensure that the vacuum furnace chamber has a leak rate of less than 0.15-0.2 mTorrx l/s, and increasing the temperature of the inner and outer cavity of the furnace to 0.5 plus minus 835 degrees C, performing a first phosphorus diffusion for the inner and outer cavity of the furnace, and then performing a second phosphorus diffusion.