Coated article with IR reflecting layer and method of making same

An IG window unit comprising:

• first and second glass substrates with a gap therebetween;
• a coating supported by the second glass substrate and facing the gap, the second glass substrate to be located closer to a building interior than is the first glass substrate, the coating comprising moving away from the second glass substrate:
• a dielectric layer comprising zirconium silicon oxynitride;
• a layer comprising zinc stannate;
• a layer comprising zinc oxide located over and directly contacting the layer comprising zinc stannate;
• an infrared (IR) reflecting layer comprising silver located on the substrate over and directly contacting the layer comprising zinc oxide;
• and
• a layer comprising metal oxide located over at least the IR reflecting layer comprising silver;
• wherein the coating contains only one silver based IR reflecting layer;
• wherein the coating has a normal emissivity (En) of no greater than 7%;
• wherein the IG window unit has a visible transmission of at least 70% and a U-value of no greater than 1.4.

A coated article including a coating supported by a glass substrate, the coating comprising moving away from the glass substrate:

• a dielectric layer comprising zirconium silicon oxynitride;
• a layer comprising an oxide of titanium located over and directly contacting the layer comprising zirconium silicon oxynitride;
• a layer comprising zinc stannate located over and directly contacting the layer comprising the oxide of titanium;
• a layer comprising zinc oxide located over and directly contacting the layer comprising zinc stannate;
• an infrared (IR) reflecting layer comprising silver located on the substrate over and directly contacting the layer comprising zinc oxide;
• and
• a layer comprising metal oxide located over at least the IR reflecting layer comprising silver;
• and
• wherein a ratio of Zr/Si (atomic) is from 0.30 to 0.47 in the layer comprising zirconium silicon oxynitride.