Patent ID: 7585396

Claim:
A method of making a coated article, the method comprising: providing a glass substrate; forming a layer comprising silver on the glass substrate; forming a layer comprising silicon nitride on the substrate over the layer comprising silver, wherein the layer comprising silicon nitride is formed on the substrate by at least sputtering a target comprising silicon; and after said sputtering, ion beam treating the layer comprising silicon nitride in a manner so as to cause the layer comprising silicon nitride to be nitrogen graded so that a portion of the layer comprising silicon nitride further from the glass substrate has a higher nitrogen content than does a portion of the layer closer to the glass substrate, and wherein said ion beam treating of the layer comprising silicon nitride is performed in a manner so as to cause a stress of the layer comprising silicon nitride to change from tensile stress to compressive stress due to the ion beam treating, and wherein the ion beam treating is performed using nitrogen gas and an ion energy from about 600-1100 eV per N 2 + ion.