TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: In the double layer aluminum nitride film, the thickness of the first layer is 30-40 nm, and the second layer is 40-50 nm. The titanium oxynitride film has thickness of 70-100 nm. The single layer aluminum film has thickness of 50-60 nm. Preferred Method: The method includes preparing aluminum film by magnetron sputtering technique, and specifically comprises taking aluminum as target material, prior to sputtering, pre-pumping pressure of 1.6x 10-4 Pa into chamber, pre-heating chamber at 200 degrees C for 60 minutes; reducing oxygen atoms on aluminum film; maintaining reaction chamber temperature at 200 degrees C; passing argon gas as working gas with a flow rate of 150 sccm; and sputtering at power of 18 W until the desired thickness of aluminum film is obtained. The method includes preparing titanium oxynitride film by magnetron sputtering technique, and specifically comprises taking titanium as target material, prior to sputtering, pre-pumping pressure of 1.6x 10-4 Pa into chamber, pre-heating chamber at 250 degrees C for 60 minutes; maintaining reaction chamber temperature at 250 degrees C; passing argon gas as working gas with a flow rate of 150 sccm; passing high purity oxygen and nitrogen as reaction gas with flow rate of 10 sccm and 70 sccm respectively, and sputtering at power of 18 W until the desired thickness of titanium oxynitride film is obtained. The method includes preparing aluminum nitride film by magnetron sputtering technique, and specifically comprises taking aluminum as target material, where the first layer of aluminum nitride film is prepared by, prior to sputtering, pre-pumping pressure of 1.6x 10-4 Pa into chamber, pre-heating chamber at 200 degrees C for 60 minutes; maintaining reaction chamber temperature at 200 degrees C; passing high purity nitrogen as reaction gas with flow rate of 40 sccm, and passing argon gas as working gas with a flow rate of 80 sccm; and sputtering at power of 6 W until the desired thickness of aluminum nitride film is obtained; and the secong layer of aluminum nitride film is prepared by, pre-pumping pressure of 1.6x 10-4 Pa into chamber, pre-heating chamber at 250 degrees C for 60 minutes; maintaining reaction chamber temperature at 250 degrees C; passing high purity nitrogen as reaction gas with flow rate of 60 sccm, and passing argon gas as working gas with a flow rate of 40 sccm; and sputtering at power of 6 W until the desired thickness of aluminum nitride film is obtained.