Chemical vapor deposition and characterization of zirconium tin titanate as a high dielectric constant material for potential electronic applications.

摘要

Integrated circuit (IC) manufacturers increasingly need new high dielectric constant (ϵ) materials for gate stacks to maintain the pace of developing faster, higher capacity CMOS and DRAM devices. Identification of new high-ϵ materials that can be integrated into current manufacturing processes is critical to the continued development of IC devices. Using magnetron sputtering and a compositional spread approach, a key composition of amorphous zirconium tin titanate (a-ZTT) films was found to exhibit a dielectric constant from 50 to 70 and leakage currents from 10−9 to 10 −7 A/cm2 at 1 MV/cm. Chemical Vapor Deposition (CVD) is an attractive technique for deposition of ZTT films because it offers several advantages over sputter deposition. Many processing parameters can be controlled and varied in the optimization of the film microstructure and composition. In addition, high-ϵ phases of the compounds might be achieved at low temperatures by using plasma enhancement of the CVD process. Alternatively, use of ozone or other oxidants may allow complete oxidation of metal precursors at lower processing temperatures.; The following discussion details the construction and modification of a CVD reactor for the deposition of ZTT thin films. In addition, characterization of a precursor “cocktail”—a solution containing all the metal components of the film—for the deposition of ZTT thin films is discussed.{09}Discussion includes experiments characterizing the dielectric and device properties (dielectric constant, dielectric loss, capacitance, and leakage current) of CVD-grown, a-ZTT thin films using the precursor “cocktail”. The importance of the relationship of the cation ratio in the precursor that is translated to the film and its relationship to the dielectric properties are shown. The device properties of ZTT films were measured using Capacitance-Voltage (CV) and Current-Voltage (IV) analysis, while dielectric properties were explored using Impedance Spectroscopy (IS), and Spectroscopic Ellipsometry (SE). In addition, X-ray Photoelectron Spectroscopy (XPS), Rutherford Backscattering (RBS), and High Resolution Transmission Electron Microscopy (HRTEM), were used to correlate compositional characteristics and investigate certain morphological characteristics.