IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Plasma Science Tuesday Sessions
       Session PS2+TF+SE-TuA

Paper PS2+TF+SE-TuA3
Electron Cyclotron Resonance Plasma Enhanced Chemical Vapor Deposition (ECR-PECVD) of ZrO@sub 2@ on Silicon

Tuesday, October 30, 2001, 2:40 pm, Room 104

Session: PECVD/IPVD
Presenter: B.O. Cho, University of California, Los Angeles
Authors: B.O. Cho, University of California, Los Angeles
J. Wang, University of California, Los Angeles
S.X. Lao, University of California, Los Angeles
J.P. Chang, University of California, Los Angeles
Correspondent: Click to Email
ZrO@sub 2@ is one of the most promising high dielectric constant (k) materials to replace SiO@sub 2@ in ultra large scale integration chip fabrication because of its wide band gap and low leakage current level. We developed an ECR-PECVD process to deposit ZrO@sub 2@ with zirconium tetra-tert-butoxide (Zr(OC@sub 4@H@sub 9@)@sub 4@) as an organometallic precursor, Ar as a carrier of the precursor vapor, and O@sub 2@ as an oxidant. Quadrupole mass spectroscopy, optical emission spectroscopy (OES), and Langmuir probe were used to characterize the plasma. The mechanisms of precursor decomposition and oxidation reactions including Zr-ligand bond dissociation and ZrO formation were investigated by analyzing the radical appearance potentials. The decomposition and oxidation reactions in the plasma were mainly controlled by the flow rate ratio of O@sub 2@ to Ar (O@sub 2@/Ar), varying between 0 and 10, and the electron temperature of 2-8 eV with the typical value of 3-4 eV. The OES intensity ratio of C@sub 2@ at 516.52 nm to O at 777.42 nm linearly scaled with the incorporated carbon concentration in the deposited film, which were determined by x-ray photoelectron spectroscopy and secondary ion mass spectroscopy. Since carbon incorporation greatly influenced the electrical performance of the film, low carbon-content, stoichiometric, and amorphous ZrO@sub 2@ was obtained at O@sub 2@/Ar>1 without substrate heating. We also deposited the film at elevated substrate temperatures around 400 °C with the controlled substrate bias to obtain carbon-free amorphous ZrO@sub 2@. The as-deposited ZrO@sub 2@ film between Al electrode and Si in capacitor devices showed good capacitance-voltage and current-voltage characteristics, which yielded k=22 and J=4x10@super -5@A/cm@super 2@ at -1.5 V, respectively. Scanning electron micrograph (SEM) showed that highly conformal film deposition could be achieved over 300 nm diameter cylindrical memory structure with an aspect ratio of 4.