Gas dispersion shield and method

A method of protecting a stepped shaped bottom surface of a gas deposition chamber having an annular shaped gas insertion channel, the method comprising:

• placing a gas dispersion shield on a stepped shaped bottom surface of a gas deposition chamber, wherein the gas dispersion shield includes a cylindrically shaped vertical sidewall having upper and lower ends, and an annular flange extending horizontally and outwardly from the sidewall upper end and having top and bottom flange surfaces and a plurality of holes formed therein extending in a non-vertical direction from the bottom flange surface to the top flange surface, with openings of the holes in the bottom flange surface being disposed over a gas insertion channel of the gas deposition chamber bottom surface;
• injecting a gas into the gas insertion channel such that the gas flows through the plurality of holes and is injected into the gas deposition chamber in a non-vertical direction;
• and
• removing the gas dispersion shield from the gas deposition chamber bottom surface.