Characterization of SiO2 films deposited at low temperature by means of remote ICPECVD

Silicon dioxide films were deposited by means of remote inductively coupled plasma enhanced chemical vapor deposition (ICPECVD) in Ar-N2O-SiH4 plasma at 150 degrees C and pressures between 1 and 6 Pa. Chemical modeling of our plasma indicated an increased fraction Of SiH3 radicals at 6 Pa (compared to SiH2, SiH, and Si species), while at 1 Pa their relative contribution on film growth should be much smaller. Layer growth from SiH3 radicals would result in better dielectric quality. We found that the films contained a high amount of positive charge and exhibited large leakage currents at 1 Pa, while films with lower positive charge and much lower leakage currents were grown at 6 Pa. The deposition rate was similar to 4.5 nm/min at 1-2 Pa and 3.5 nin/min at 6 Pa. The lower growth-rate at 6 Pa could be ascribed to the formation of denser films, as well as to the changing plasma and surface chemistry. These results were consistent with chemical modeling. (c) 2007 Elsevier B.V All rights reserved.