Micro-disk resonators were fabricated using Er doped silicon-rich silicon nitride (SRSN:Er). SRSN:Er thin films are
fully CMOS-compatible and show efficient Er3+ luminescence pumped off-resonantly via Si nanoclusters. The high
refractive index of SRSN (>2.0 at 1.5 um) allows freedom in designing compact micro-disk resonators. Micro-disks with
two different contents of Er (0.2 at.%, 0.02 at.%) with a diameter of 25 um were fabricated, and characterized using
evanescent coupling using tapered fibers. Whispering gallery modes with Q-factors in excess of 13000 were obtained,
and FDTD calculations indicate that much higher values should be possible. Finally, we demonstrate excitation of
fundamental whispering gallery mode via off-resonant, top-pumping of the SRSN microdisk.