| The Holy Grail in CVD community is to find precursors that can afford the following: good nucleation on a desired substrate and conformal deposition in high AR features. Good nucleation is not only necessary for getting ultra-thin films at low thicknesses; it also offers films that are smooth at higher thickness values. On the other hand, conformal deposition enables uniform film coating on 3D structures. These two properties would meet the demands from most of the technology. However, it turns out that most growth precursor molecules can not fulfill both the requirements. For good nucleation characteristics, it is required that the precursor has a high sticking probability on the substrate, whereas, for conformal deposition, the sticking probability of the precursor molecule on the growth surface has to be lower. Therefore, to achieve both of these characteristics, it is imperative to control the reaction surface. My research is focused on finding methods to change the growth surface adequately, so as to render good nucleation properties by enhancing sticking probability during nucleation stage, and to decrease the sticking probability during growth, for conformal deposition. A combination of these can fulfill most of the future technological requirements. I have developed a new way of nucleation enhancement: by activating the surface with remote noble gas plasma. Conformality enhancement is achieved by use of growth inhibitors that lower the sticking probability of the molecules impinging the growth surface. |
