AVS 49th International Symposium
    Plasma Science Wednesday Sessions
       Session PS+TF-WeP

Paper PS+TF-WeP2
Tuning the Material and Electrical Characteristics of ZrO@sub 2@ Film Obtained by Plasma Enhanced Chemical Vapor Deposition

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Plasma Etching & Deposition
Presenter: J.P. Chang, University of California, Los Angeles
Authors: B. Cho, University of California, Los Angeles
J.P. Chang, University of California, Los Angeles
Correspondent: Click to Email
ZrO@sub 2@ was investigated as a dielectric to replace SiO@sub 2@ for dynamic random memory (DRAM) capacitor. ZrO@sub 2@ films were deposited on p-Si (100) wafers by ECR-PECVD using zirconium tetra-tert-butoxide (Zr(OC@sub 4@H@sub 9@)@sub 4@)) as an organometallic precursor, Ar to carry the precursor vapor, and O@sub 2@ as oxidant. We used optical emission spectroscopy (OES), Langmuir probe, and quadrupole mass spectrometry (QMS) to characterize the gas phase. Atomic force microscopy results showed that the ZrO@sub 2@ surface was very smooth with rms=1.4 Å as long as O@sub 2@/Ar was set to over one. X-ray diffraction showed that the films were amorphous. X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry indicated that stoichiometric ZrO@sub 2@ film was obtained with various amount of carbon incorporation depending on the electron temperature and the O@sub 2@ /Ar. We obtained a linear dependence of the carbon content determined by XPS upon the OES intensity ratio of molecular carbon and atomic oxygen. High resolution transmission electron microscopy was used to observe the interfacial layer formation between the deposited ZrO@sub 2@ and the substrate Si. Fourier transform infrared spectroscopy was used to investigate the hydrocarbon composition in the film. The electrical properties of the as-deposited ZrO@sub 2@ were assessed by forming Al/ZrO@sub 2@/Si capacitor structures. We obtained the maximum dielectric constant of 16 at O@sub 2@/Ar=1. C-V curves shifted to higher bias voltage with increasing O@sub 2@ /Ar, which indicated more negative fixed charges were introduced into the film as we add more O@sub 2@ in the gas phase. We observed that the leakage current density decreased drastically with increasing O@sub 2@/Ar. ZrO@sub 2@ film at O@sub 2@/Ar=4 showed 3.3x10@super -6@ A/cm@super 2@ at equivalent oxide thickness of 25 Å.