Smooth, Low-Resistance, Pinhole-free, Conformal Ruthenium Films by Pulsed Chemical Vapor Deposition

Ruthenium (Ru) thin films were deposited by pulsed chemical vapor deposition with precursors bis(N,N′-di-tert-butylacetamidinato)ruthenium(II)dicarbonyl, ammonia and hydrogen. Low-resistance polycrystalline Ru films with bulk density were obtained. Good adhesion to $SiO_2$ substrates was achieved by introducing a thin layer of WN in between the Ru and the $SiO_2$. Ru films only $\sim 2$ nm thick fully covered the WN layer without any pinholes. Deposition of Ru inside narrow holes showed that good conformality was obtained by lowering the deposition temperature. The film surface was smooth, and the rms roughness value did not increase too much after rapid thermal annealing at 700°C.Chemistry and Chemical Biolog

Surface Chemistry of Copper Precursors in Connection with Atomic Layer Deposition (ALD) Processes

Chemistry and Chemical Biolog

Atomic Layer Deposition of Tin(II) Sulfide

Chemistry and Chemical Biolog

Low Temperature Epitaxial Growth of High Permittivity Rutile TiO2TiO_2 on SnO2SnO_2

Thin films of high dielectric constant $\kappa \sim 68$ rutile phase titanium dioxide $TiO_2$ were grown epitaxially on tin dioxide $SnO_2$ substrates, which are a low cost, more abundant alternative to ruthenium electrodes used previously. Atomic layer deposition at low temperature ${250^\circ C}$ was used with titanium(IV) tetrakis(isopropoxide) and hydrogen peroxide $H_2O_2$ as precursors. The rutile $TiO_2$ thin films have crystalline grains that match the structure and orientation of the grains in the polycrystalline rutile phase $SnO_2$ substrates. The epitaxial relations can be clearly identified from the continuous lattice fringes across the interfaces.Chemistry and Chemical BiologyOther Research Uni

Overview of ALD Precursors and Reaction Mechanisms

Successful use of ALD requires suitable chemical precursors used under reaction conditions that are appropriate for them. There are many requirements for ALD precursors: sufficient volatility, thermal stability and reactivity with substrates and with the films being deposited. In addition, it is easier to produce the required vapors if the precursor is liquid at room temperature, or if it is a solid with melting point below the vaporization temperature, or if it is soluble in an inert solvent with vapor pressure similar to that of the precursor. The precursor vapor should not etch or corrode the substrate or deposited film. Ideally, the precursors should be non-flammable, non-corrosive, non-toxic, simple and non-hazardous to make and inexpensive.Chemistry and Chemical Biolog

Selective Vapor Deposition

Chemistry and Chemical Biolog

Atomic Layer Deposition of Tin Oxide with Nitric Oxide as an Oxidant Gas

Atomic layer deposition (ALD) of tin oxide $(SnO_2)$ thin films was achieved using a cyclic amide of Sn(II) (1,3-bis(1,1-dimethylethyl)-4,5-dimethyl-(4R,5R)-1,3,2-diazastannolidin-2-ylidene) as a tin precursor and nitric oxide (NO) as an oxidant gas. Film properties as a function of growth temperature from $130-250^{\circ}C$ were studied. Highly conducting $SnO_2$ films were obtained at $200-250^{\circ}C$ with the growth per cycle of $~1.4 \mathring{A}$/cycle, while insulating films were grown at temperatures lower than $200^{\circ}C$. Conformal growth of $SnO_2$ in holes of aspect-ratios up to ~50 : 1 was successfully demonstrated.Chemistry and Chemical Biolog

Filling Narrow Trenches by Iodine-Catalyzed CVD of Copper and Manganese on Manganese Nitride Barrier/Adhesion Layers

We present a process for the void-free filling of sub-100 nm trenches with copper or copper-manganese alloy by chemical vapor deposition (CVD). Conformally deposited manganese nitride serves as an underlayer that initially chemisorbs iodine. CVD of copper or copper-manganese alloy releases the adsorbed iodine atoms from the surface of the manganese nitride, allowing iodine to act as a surfactant catalyst floating on the surface of the growing copper layer. The iodine increases the growth rate of the copper and manganese by an order of magnitude. As the iodine concentrates near the narrowing bottoms of features, void-free, bottom-up filling of CVD of pure copper or copper-manganese alloy is achieved in trenches narrower than 30 nm with aspect ratios up to at least 5:1. The manganese nitride films also show barrier properties against copper diffusion and enhance adhesion between copper and dielectric insulators. During post-deposition annealing, manganese in the alloy diffuses out from copper through the grain boundaries and forms a self-aligned layer that further improves adhesion and barrier properties at the copper/insulator interface. This process provides nanoscale interconnects for microelectronic devices with higher speeds and longer lifetimes.Chemistry and Chemical Biolog

Atomic Layer Deposited Zinc Tin Oxide Channel for Amorphous Oxide Thin Film Transistors

Bottom-gate thin film transistors with amorphous zinc tin oxide channels were grown by atomic layer deposition (ALD). The films maintained their amorphous character up to temperatures over 500 $^{\circ}$C. The highest field effect mobility was ~13 $cm^2/V^.s$ with on-to-off ratios of drain current ~10$^9$-10$^{10}$. The lowest subthreshold swing of 0.27 V/decade was observed with thermal oxide as a gate insulator. The channel layers grown at 170 $^{\circ}$C showed better transistor properties than those grown at 120 $^{\circ}$C. Channels with higher zinc to tin ratio (~3-4) also performed better than ones with lower ratios (~1-3).Physic

Atomic layer deposition of Zn(O,S) thin films with tunable electrical properties by oxygen annealing

Zinc oxysulfide, Zn(O,S), films grown by atomic layer deposition were annealed in oxygen to adjust the carrier concentration. The electron carrier concentration of Zn(O,S) can be reduced by several orders of magnitude from $10^{19}$ to $10^{15} cm^{−3}$ by post-deposition annealing in oxygen at temperatures from 200 °C to 290 °C. In the case of Zn(O,S) with S/Zn = 0.37, despite the considerable change in the electron carrier concentration, the bandgap energy decreased by only ∼0.1 eV, and the crystallinity did not change much after annealing. The oxygen/zinc ratio increased by 0.05 after annealing, but the stoichiometry remained uniform throughout the film.Chemistry and Chemical BiologyEngineering and Applied Science