(Ba,Sr)TiO3 (BST) thin films with thicknesses ranging from 15 to 50 nm are prepared by a rf magnetron sputtering on Pt/SiO2/Si substrates. The dielectric constants of BST thin films increase with increasing deposition temperature and thicknesses. The leakage current increases with increasing deposition temperature and this prevents the deposition temperature of the 20 nm thick BST thin film from being increased to a value more than 640 °C. The leakage current is also critically dependent upon the postannealing temperature and atmosphere after the top electrode fabrication. The dielectric constant increases with increasing postannealing temperature which further reduces the SiO2 equivalent thicknesses of the BST thin films. A 20 nm thick BST thin film deposited at 640 °C and postannealed at 750 °C under N2 atmosphere for 30 min, shows a SiO2 equivalent thickness of 0.24 nm, dielectric dissipation factor less than 1%, and leakage current of about 40 nA/cm2 at ∓1.5 V.

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Electrical conduction mechanisms for Pt/(Ba0.5Sr0.5)TiO3 (BST)/Pt, IrO2/BST/IrO2, and Pt/BST/IrO2 capacitors were studied. The Pt/BST/Pt capacitor shows a Schottky emission behavior with interface potential barrier heights of about 1.5–1.6 eV. The barrier height is largely determined by the surface electron trap states of the BST. The IrO2/BST interface shows an ohmic contact nature due to the elimination of the surface trap states as the result of the formation of strong chemical bonds between the IrO2 and BST which results in the Poole–Frenkel emission conduction mechanism. Pt/BST/IrO2 capacitor shows Schottky emission behavior and a positive temperature coefficient of resistivity (PTCR) effect depending on the bias polarity. The electron trap states at the Pt/BST interface and the positive space charges within the carrier depletion layer result in the PTCR effect.

The electrical conduction properties of rf sputter-deposited (Ba, Sr)TiO3 (BST) films on Pt and IrO2 electrodes and metalorganic chemical vapor deposited (MOCVD) BST films on a Pt electrode were investigated and a new energy band model that satisfactorily explains the observed leakage current characteristics and film thickness dependent dielectric properties is proposed. The BST and Pt junction constituted a blocking contact with interface potential barrier heights of 1.6–1.7 eV and 1.2 eV for the sputtered and MOCVD films, respectively. Schottky emission behavior was observed at measurement temperatures higher than 120 °C and tunneling related conduction behavior appeared below that temperature for a film thickness of 40 nm. A partial depletion model with a very thin (about 1 nm) layer devoid of space charge at the interface with the Pt electrode is proposed to explain the V1/2 dependent variation of ln(Jo) as well as the decreasing dielectric constant with decreasing film thickness.

Conduction band-edge effective work functions (φ m,eff ) are demonstrated with TaC x and TiN by means of La 2 O 3 capping of HfSiO x in a gate-first process flow with CMOScompatible thermal budget. With TaC x , a 10-Å-thick La 2 O 3 cap results in a φ m,eff of 3.9 eV with a low equivalent oxide thickness (EOT) increase (1-2 Å) and unaffected electron mobility. With TiN, non-nitrided La 2 O 3 capping results in a smaller φ m,eff reduction at a larger EOT increase, while with post-cap nitridation, the TiN φ m,eff is lower at a smaller EOT increase. Results show that the choice of metal and nitridation conditions have significant effects on La 2 O 3 capped stacks.

Metal-oxide-semiconductor devices on p -type Ge with La 2 O 3 and ZrO 2 / La 2 O 3 as gate dielectric and the effect of postmetallization anneal Structural and dielectric properties of thin ZrO 2 films on silicon grown by atomic layer deposition from cyclopentadienyl precursor Reaction/annealing pathways for forming ultrathin silicon nitride films for composite oxide-nitride gate dielectrics with nitrided crystalline silicon-dielectric interfaces for application in advanced complementary metal-oxide-semiconductor devices