High Purity Hydrazine Gas for near Stoichiometric Low Temperature Titanium Nitride ALD
Advanced integrated circuit (IC) manufacturing requires precision films with low resistivity for contact barriers, liners and electrodes. Titanium Nitride is a promising material for this purpose, and hydrazine gas is an effective low temperature nitride source. This gas is now available with a delivery system that ensures safer, uniform, high purity nitridation.
Emerging Requirements for Hydrazine Gas
Titanium Nitride (TiN) is a widely used metal barrier and liner material in semiconductor manufacturing due to its high diffusion barrier performance and good adhesion properties between several disparate materials.
Increasingly, application requirements are driving manufacturers to use atomic layer deposition (ALD) techniques to achieve step coverage as devices shrink and aspect ratios grow. The TiN layer must be highly conformal with minimal resistivity for device operation at high frequency. This can be particularly challenging with three dimensional structures and contact holes with high aspect ratios. Thermal budget and ultra-high purity constraints lead to additional challenges for Process Engineers.
Minimizing Parasitic Losses
Parasitic losses are a major problem due to resistivity of barrier and liner films in smaller devices. Films must be much thinner, have greater conformality and as few interfacial defects as possible. In addition, these conditions must be met at sub-350C temperatures, because of the highly limited thermal budget of new materials.
Films from Hydrazine Gas
TiN films resulting from use of hydrazine gas meet the requirements for several applications.
- Deposition by thermal ALD at 350C or lower temperatures
- Resistivity at 200 ohms or lower
- Defects minimal with very low surface roughness
- Oxygen-free process, removing significant contamination source
Low Temperature Nitride Source
Alternative methods for low temperature metal nitride ALD have inherent problems:
- Plasma NH3 methods have very slow deposition rates below 400C. Plasma NH3 also has uniformity problems with three-dimensional structures and significant hydrogen incorporation.
- Commonly available liquid hydrazine presents safety problems and contains high concentrations of water contamination. This leads to oxygen-related defects and high resistivity which make this source a non-viable option.
In contrast, BRUTE Hydrazine enables TiN formation at low temperature (sub-350C) and with low resistivity. BRUTE Hydrazine is hydrazine gas delivered in a specialty membrane-based delivery system that makes the chemical easier to handle, safer to use and virtually water free.
The BRUTE Hydrazine Difference
BRUTE Hydrazine was specifically designed to enable semiconductor manufacturers to harness the highly reactive properties of hydrazine for nitride deposition involving advanced materials. BRUTE Hydrazine is packaged with a solvent for stability and safety. The BRUTE Hydrazine membrane-based delivery system leaves both the solvent and any contaminants behind while delivering highly pure hydrazine gas to process.
BRUTE Hydrazine is available in multiple sizes. The Laboratory version can be easily connected to laboratory tools and requires only vacuum draw. Chemical volume is low, reducing special safety handling requirements. BRUTE Hydrazine is also available in larger sizes that can connect to tools with purge gas and can also operate with a carrier gas.