We investigate the catastrophic mirror damage (CMD) of 980-nm GaAs pump laser packages. Scanning electron microscopy with an energy dispersive X-ray on the CMD site indicates that in the absence of oxygen such failure at the front facet is attributed to carbon compounds, existing on the surface of the laser housing. X-ray photoelectron spectroscopy (XPS) analysis on the surface exposed to UV-ozone exhibits a decrease in carbon and an increase in oxygen, which is in good agreement with the decrease in the contact angle measurements. Fourier transform infrared (FTIR) spectroscopy confirms that for the laser packages with the CMD the surface has been contaminated by the carbon-based organic contaminants. The accelerated aging test demonstrates that the laser packages without oxygen but UV-ozone cleaned do not show the CMD. This result suggests that the CMD could be suppressed by the UV-ozone treatment without oxygen in the package. (C) 2004 Elsevier B.V. All rights reserved.