Abstract: Various showerheads and methods are provided. A showerhead may include a faceplate partially defined by a front surface and a back surface, a back plate having a gas inlet, a first conical frustum surface, and a second conical frustum surface, a plenum volume fluidically connected to the gas inlet and at least partially defined by the gas inlet, the back surface of the faceplate, the first conical frustum surface, and the second conical frustum surface, and a baffle plate positioned within the plenum volume, and having a plurality of baffle plate through-holes extending through the baffle plate. The second conical frustum surface may be positioned radially outwards from the first conical frustum surface with respect to a center axis of the showerhead, and the second conical frustum surface may be positioned along the center axis farther from the gas inlet than the first conical frustum surface.