AVS 51st International Symposium
    Electronic Materials and Processing Tuesday Sessions
       Session DI+PS-TuM

Paper DI+PS-TuM9
Investigation of the Roles of Oxygen Plasma and Solvent in the Pulsed-Liquid Injection PE-MOCVD Deposition of Y@sub2@O@sub3@ High-@kappa@ Materials in MIM Structures

Tuesday, November 16, 2004, 11:00 am, Room 304C

Session: High-k Dielectrics: Growth and Processing
Presenter: C. Vallee, CNRS, France
Authors: C. Vallee, CNRS, France
C. Durand, CNRS, France
M. Derivaz, CNRS, France
M. Kahn, CNRS, France
M. Bonvalot, CNRS, France
Correspondent: Click to Email
CMOS scaling and Metal-insulator-Metal (MIM) capacitance density improvement will require use of new high-@kappa@ dielectric material in a near future. We have focused our work on the elaboration of Y2O3 thin films at low thermal budget (350°C) by pulsed-liquid injection Plasma Enhanced MOCVD for MIM capacitors (TiN-Y2O3-TiN). In this technique, dissolved Yttrium @beta@-diketonate Y(tmhd)@sub 3@ precursors (in cyclohexane and octane) are sequentially injected into an evaporator, with accurate reproducibility in the amount of precursors delivered to a low frequency (380 KHz) plasma chamber, where a O@sub 2@ plasma is applied to induce precursor decomposition and surface reactivity. The respective roles of oxygen plasma and solvent composition in the Y2O3 high-@kappa@ materials characteristics and interface properties have been investigated. The plasma is monitored by optical emission spectroscopy (OES) while films and interfaces are mainly characterized by X-rays Photoelectron Spectroscopy (XPS). Electrical characterizations are also performed in order to obtain capacitance density, voltage linearity and electrical breakdown properties. We have shown that a low plasma power and a high pressure limit carbon contamination while a high injection frequency limits interface reactions (as observed on SiO2/Si substrates). With this technique a capacitance density up to 6 fF/µm@super 2@ has been obtained. We have also investigated the effects of two solvents, cyclohexane and octane, in this study : it has been observed that deposition rate is strongly influenced by solvent nature. In addition, we also studied the effect of nitrogen plasma before, during and after deposition. Chemical bonding, concentration, and distribution of N in Y-oxide films after deposition and after high-temperature annealings are also characterized. The N concentration distribution in high-k dielectrics is likely to be an important factor to achieve optimal electrical performances.