ON THE REACTION SCHEME FOR TI TIN CHEMICAL-VAPOR-DEPOSITION (CVD) PROCESS USING TICL4/

A schematic reaction mechanism is proposed to explain the Ti/TiN chemi cal vapor deposition (CVD) process using the TiCl4 molecule as the sou rce species. The scheme can be considered as two successive steps: (I) TiCl4 molecules are adsorbed onto surface reactive sites through conc erted electron delocalizations, (II) ambient reducing agents such as H -2 or NH3 reactively eliminate Cl atoms from Ti atoms in the form of H Cl. Preliminary molecular orbital (MO) calculations indicate that step (I) is an energetically easy process. Conversely, step (II) is expect ed to be the rate-determining process with a considerable activation e nergy. As a whole, the characteristics of resultant CVD films (e.g., t he conformality) are probably controlled not by the TiCl4-adsorption s tep (I) but by the Cl elimination step (II).