Brian J. Daniels

Diffusion of Copper in Titanium Zirconium Nitride Thin Films

Honeywell Electronic Materials Star Center, Sunnyvale, California, USAThe diffusion coefficient of Cu in~Ti, Zr!N was measured by X-ray diffraction~XRD! and four-point probe~FPP! analyses afterannealing Cu/~Ti, Zr!N/Si multilayered samples in the temperature range of 500-900°C. Cu diffusion in~Ti, Zr!N had componentsfrom both the grain boundaries and the lattice based on diffusional analysis. This study suggests that for the measurement of thediffusion coefficient of Cu, FPP analysis is more precise and sensitive than XRD analysis. Additionally,~Ti, Zr!N has better Cudiffusion barrier properties than those of TaN and TiN.© 2004 The Electrochemical Society. @DOI: 10.1149/1.1644355# All rights reserved.Manuscript received May 1, 2003. Available electronically January 22, 2004.

Growth of (Ti,Zr)N Films on Si by DC Reactive Sputtering of TiZr in N 2 / Ar Gas Mixtures Effect of Flow Ratio

Titanium zirconium nitride [(Ti,Zr)N] films were prepared on Si substrates by dc reactive magnetron sputtering from a Ti-5 atom % Zr alloy target in N 2 /Ar gas mixtures. Material characteristics of the (Ti,Zr)N films were investigated by X-ray photoelectron spectroscopy, four-point probe, X-ray diffraction, atomic force microscopy, and cross-sectional transmission electron microscopy. According to those results, the deposition rate, chemical composition, crystalline structure, and film resistivity of the deposited films correlate with the N 2 /Ar flow ratio. The microstructure of the (Ti,Zr)N films was an assembly of very small columnar crystallites with a rock-salt (NaCI) structure and an enlarged lattice constant (over pure TiN). A minimum film resistivity of 59.3 μΩ cm was obtained at an N 2 /Ar flow ratio of 2.75, corresponding to near stoichiometric film composition [N/(Ti,Zr) = 0.96] and crystalline structure.

Characteristics of DC Reactively Sputtered (Ti,Zr)N Thin Films as Diffusion Barriers for Cu Metallization

(Ti,Zr)N films were prepared by dc reactive magnetron sputtering from a Ti-5 atom % Zr alloy target in N 2 /Ar gas mixtures and then employed as diffusion barriers between Cu thin films and Si substrates. Material characteristics of the (Ti,Zr)N film were investigated by X-ray photoelectron spectroscopy and cross-sectional transmission electron microscopy (XTEM). The (Ti,Zr)N film microstructure was an assembly of Very small columnar crystallites with a rock-salt (NaCI) structure. Metallurgical reactions of Cu/(Ti,Zr)N 0 . 9 5 /Si, Cu/(Ti,Zr)N 0 . 7 6 /Si, and Cu/TaN 0 . 7 1 /Si were studied by X-ray diffraction and sheet resistance measurements. The variation percentage of sheet resistance for all Cu/barrier/Si systems stayed at a constant value after annealing up to 500°C for 30 min. However, the sheet resistance increased dramatically after annealing above 750°C for Cu/(Ti,Zr)N 0 . 9 5 /Si, and 500°C for both Cu/(Ti,Zr)N 0 . 7 6 /Si and Cu/TaN 0 . 7 1 /Si. For these samples, the interface deteriorated seriously and formationof Cu 3 Si was observed by XTEM. Our results suggest thai the refractory binary metal nitride film, (Ti,Zr)N, can be used as a diffusion barrier for Cu metallization as compared to the well-known TaN film.

65.2: Spin-On Polymers for TFT Gate Dielectric Application and Planarization of Stainless Steel

We present spin-on polymer films with significantly improved dielectric properties for TFT gate dielectric applications. Breakdown voltage//leakage current//CV hysteresis are 4.10 MV/cm at 1 μA/cm2//4.9 × 10−8 A/cm2 at 2.5 MV/cm//3.4 V and 4.73 MV/cm//2.6 × 10−8 A/cm2//0.44V at curing temperatures of 250 °C and 425 °C, respectively. In addition, we present our recent results using spin-on dielectrics to planarize and insulate stainless steel substrates for flexible displays and high resolution QVGA mobile displays.

Spin-on Gate Dielectric Materials for Next Generation Display Systems

We present recent advances on spin-on polymers as gate dielectric for thin film transistors. We have developed film type I with significantly improved dielectric properties. At a curing temperature of 250 °C, the dielectric constant is 3.46, the breakdown voltage is 4.10 MV/cm at 1 μA/cm 2 , the leakage current is 4.9 × 10 −8 A/cm 2 at 2.5 MV/cm, and the CV hysteresis is 3.4 V. At a curing temperature of 425 °C, the dielectric constant, the breakdown voltage, the leakage current, and the CV hysteresis are 3.2, 4.73 MV/cm, 2.6 × 10 −8 A/cm 2 , and 0.44 V respectively.