OXYGEN-CONTENT OF SUBSTRATES AND TUNNEL OXIDE QUALITY - AN IN-LINE SYSTEMATIC ANALYSIS

An experimental study is presented concerning the impact of several su bstrate parameters on the reliability of thin oxides in an actual devi ce process. Our results show that some bulk properties have a relevent impact on wafer performances. For instance, the reliability of thin o xide is found to be sensitive to variations of initial interstitial ox ygen concentration within a rather narrow range. Epitaxial substrates give the best performances, provided suitable extrinsic gettering is u sed. On the contrary the behavior of thin oxides is found not to be ve ry sensitive to the status (in terms of light point defects) of the wa fer surface at the beginning of the device process.