Atomic Layer Deposition TiN Research Articles

Thermal stability of TiN metal gate prepared by atomic layer deposition or physical vapor deposition on HfO2 high-K dielectric

In this paper, the thermal stability of TiN metal gate with various composition prepared by different preparation technology [(e.g., atomic layer deposition (ALD) or physical vapor deposition (PVD)] on HfO2 high-K dielectric is investigated and compared by physical and electrical analysis. After annealing of the TiN/HfO2 stack at 1000 °C for 30 s, it is observed that: (1) Nitrogen tends to out-diffuse from TiN for all the samples; (2) Oxygen from the interfacial layer (IL) between HfO2 and Si tends to diffuse toward TiN. PVD Ti-rich TiN shows a wider oxygen distribution in the gate stack, and a thinner IL than the N-rich sample. Ti penetration into HfO2 is also observed in the Ti-rich sample, which can potentially lead to the dielectric break-down. Besides, the oxygen out-diffusion can be significantly suppressed for ALD TiN compared to the PVD TiN samples.

Texture of atomic layer deposited ruthenium

Ruthenium films were grown by plasma enhanced atomic layer deposition (ALD) on Si(1 0 0) and ALD TiN. X-ray diffraction (XRD) showed that the as-deposited films on Si(1 0 0) were polycrystalline, on TiN they were (0 0 2) oriented. After annealing at 800 °C for 60 s, all Ru films were strongly (0 0 2) textured and very smooth. Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) demonstrated that the lateral grain size of the annealed films was several 100 nm, which was large compared to the 10 nm thickness of the films. No ruthenium silicide was formed by annealing the ALD Ru films on Si(1 0 0). Comparison with sputter deposited films learned that this occurred because the ammonia plasma created a SiO x N y reaction barrier layer prior to film growth.

Threshold Voltage Modulation Technique using Fluorine Treatment through Atomic Layer Deposition TiN Suitable for Complementary Metal–Oxide–Semiconductor Devices

We propose a fluorine (F) treatment technique that is suitable for threshold voltage (Vth) modulation in p-channel metal–oxide–semiconductor field-effect transistors (PMOSFETs) with the atomic layer deposition (ALD) TiN/HfO2 gate structure. A work function near the band edge is achieved using the F treatment technique without the degradation of hole mobility in PMOSFETs. Vth shift value is almost the same regardless of gate length. The barrier height shift attributable to the F treatment corresponds closely to the Vth shift. It is found that the F treatment technique modulates the effective work function. No Vth shift in n-channel MOSFET (NMOSFETs), namely, the ALD-TiN/HfSix/HfO2 gate stack structure, is observed with F treatment. It is confirmed that F treatment is a suitable technique for complementary MOSFET (CMOSFETs) due to the confinement of Vth shift only to PMOSFETs.

Impact of Metal Gate Deposition Method on Characteristics of Gate-First MOSFET with Hf-Silicate

This paper compares metal oxide semiconductor field effect transistor (MOSFET) characteristics of TiN metal gate deposited by atomic layer deposition (ALD) and chemical vapor deposition (CVD) on Hf-based high- dielectrics. Despite many similarities between these two techniques, clear differences were found in device characteristics such as equivalent oxide thickness (EOT), mobility, dopant diffusion, and trap generation. ALD TiN results in a thicker EOT than CVD TiN due to its inherent purging cycle and higher process temperature, but it has a stronger resistance to dopant diffusion. The ALD TiN process also provides better interfacial characteristics, thus better device performance.

Stability of Plasma Posttreated TiN Films Prepared by Alternating Cyclic Pulses of Tetrakis-Dimethylamido-Titanium and Ammonia

The effect of plasma posttreatment on the resistivity and stability of tetrakis-dimethylamido-titanium (TDMAT)-based atomic layer deposition TiN films was investigated. Posttreatment with hydrogen plasma was effective for lowering the resistivity of the TiN films and also for improving their stability in air. Longer plasma pulse times with high power yielded films of lower resistivity aand increased stability in air. However, there was no noticeable improvement of the film's stability with nitrogen plasma gas.

Growth mechanism and continuity of atomic layer deposited TiN films on thermal SiO2

In atomic layer deposition (ALD), film thickness control by counting the number of deposition sequences is poor in the initial, nonlinear growth region. We studied the growth of TiN films formed by sequentially controlled reaction of TiCl4 and NH3 on thermal SiO2 during the transient, nonlinear period. Using low-energy ion scattering and Rutherford backscattering spectroscopy analysis, we have found that a three-dimensional growth of islands characterizes the ALD TiN growth on SiO2. Growth at different temperatures (350 °C and 400 °C) affects the extent of the transient region and the rapid closure of the film. At 400 °C, a reduced growth inhibition and an earlier start of three-dimensional growth of islands results in film closure at about 100 cycles, corresponding to a TiN thickness of 24±3 Å. At 350 °C the minimum thickness at which the TiN layer becomes continuous is 34±3 Å, deposited with 150 cycles.

Impact of atomic-layer-deposited TiN on the gate oxide quality of W/TiN/SiO2/Si metal–oxide–semiconductor structures

We demonstrate the impact of atomic-layer-deposited TiN gate on the characteristics of W/TiN/SiO2/p-Si metal–oxide–semiconductor (MOS) systems. Damage-free gate oxide quality was attained with atomic-layer-deposition (ALD)–TiN as manifested by an excellent interface trap density (Dit) as low as ∼4×1010 eV−1 cm−2 near the Si midgap. ALD–TiN improved the Dit level of MOS systems on both thin SiO2 and high-permittivity (high-k) gate dielectrics. The leakage current of a MOS capacitor gated with ALD–TiN is remarkably lower than that with sputter-deposited TiN and poly-Si gate at the similar capacitance equivalent thickness (CET). Less chlorine content in ALD–TiN films appears to be pivotal in minimizing the CET increase against postmetal anneal and improving gate oxide reliability, paving a way for the direct metal gate process.

TiN Diffusion Barrier Grown by Atomic Layer Deposition Method for Cu Metallization

The effects on the impurity content, microstructure, resistivity and barrier characteristics of TiN film deposited by an atomic layer deposition (ALD) method have been evaluated. The TiN films were deposited on Si(100) substrates at 450°C using the reactant gases TiCl4 and NH3. The chemical and physical properties of ALD TiN thin films were measured. The TiN films had a randomly-oriented columnar grain microstructure. The chlorine content in the films was below the detection limit of Auger electron spectroscopy (<0.5 at.%) due to the complete surface reaction by self-limiting reaction in ALD method. This low Cl content in film induced a low film resistivity of 120 µΩcm. The barrier properties of this ALD films were tested by the etch-pit method. The result showed a retardation of the interdiffusion between Cu and Si in samples annealed for one hour at temperatures up to 450°C.