AVS 49th International Symposium
    Dielectrics Thursday Sessions
       Session DI+EL-ThA

Paper DI+EL-ThA3
Formation of Al Oxynitride Alloys by Low-temperature Remote Plasma Nitridation

Thursday, November 7, 2002, 2:40 pm, Room C-107

Session: Processing and Properties of Dielectric Materials
Presenter: C. Hinkle, North Carolina State University
Authors: C. Hinkle, North Carolina State University
G. Lucovsky, North Carolina State University
Correspondent: Click to Email
Remote rf plasma nitridation of plasma deposited Al@sub 2@O@sub 3@ films was studied. Online Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS), and nuclear resonance profiling (NRP) are used to characterize the composition and spatial distribution of the resultant films. Al@sub 2@O@sub 3@ films were deposited by remote plasma enhanced chemical vapor deposition (RPECVD). Nitridation was carried out using 30 W rf power and a substrate temperature of 300 C. Nitrogen was introduced upstream diluted with Helium in a 60:160 ratio, and the process pressure was varied from 0.0325 Torr to 0.3 Torr. Nitridation at lower process pressures allows the plasma to extend into the processing chamber and results in greater nitrogen incorporation. Previous studies of nitrided SiO@sub 2@ have shown different fundamental nitridation mechanisms depending on process pressure and identified through different nitridation kinetics. In those experiments, low pressure nitridation in the plasma glow resulted in top surface nitridation by N@sub 2@@super +@ ions while high pressure nitridation with the plasma confined in the generation tube produced uniform nitridation throughout the film via N atoms. A kinetics study of the plasma-nitrided Al@sub 2@O@sub 3@ films shows the data to fit an expression of the form, [N] = A {1-exp(-Bt@sub N@)}, where A increases inversely and exponentially with process pressure, B is a time constant that remains constant (within 10%) as process pressure changes, and t@sub N@ is the nitridation time in minutes. The fact that the time constant remains constant suggests that there is a single mechanism for the nitridation of Al@sub 2@O@sub 3@ that is associated with the N@sub 2@@super +@ ions that impinge on the oxide film.