We demonstrate Si3N4 photonic integrated circuits featuring ultra-low propagation loss and tight optical confinement, fabricated with a subtractive process. We report an increase in propagation loss in Si3N4 waveguides after exposure to ultraviolet (UV) irradiation, and loss recovery following a rapid thermal anneal (RTA). We show an intrinsic quality factor as high as 20×106 at 1.55 µm across a 100 mm wafer.