Low Temperature Nitrides
Emerging materials, 3-dimensional structures, and new display technologies impose thermal constraints on deposition methods.
Key Challenges for Device Performance
Parasitic Losses
Device performance and size are limited by material heat tolerance in Middle of the Line (MOL) and Back-End of the Line (BEOL) processes. Improved metal contacts, thinner barrier layers and thinner liners are required to minimize parasitic losses as devices shrink.
New Channel Materials
Current processes for next generation channel materials in logic devices are inadequate. Integration imposes new low temperature constraints for several process steps including TiN electrode, AlN2 heat spreader, GaN, and SiN side wall deposition.
Vertical Scaling
Memory density requirements for future 3-D NAND devices requires large increases in vertical scaling. Temperature limits on SiN deposition will continue to decrease from 550°C.
Solving Device Performance Challenges
Low Temperature
Hydrazine gas creates low resistivity TiN, SiN, AlN2, GaN, and InGaN films by growing nitrides at lower temperatures than with ammonia.
Uniform High Aspect Ratio Deposition
Hydrazine gas deposits uniform nitride film on high aspect ratio (HAR) features to create effective sidewall materials. This deposition is effective at temperatures as low as 320°C-350°C.
High Density, Low WER
Hydrazine gas builds high density, low wet-etch-rate (WER) SiN . Operating temperatures can be as low as 450°C-550°C.
Technical Brief: Effective Silicon and Metal Nitride Deposition at Reduced Temperature
Hydrazine Gas as a Nitride Source
Low Temperature, High Aspect Ratio
Hydrazine is an excellent low temperature thermal ALD nitride source. Next generation devices have low thermal budgets and high aspect ratio structures that create new challenges for conformal III-V nitride films. Old solutions cannot meet these new challenges. Nitrogen from ammonia does not yield quality films below 400°C. Plasma delivery does not uniformly coat internal side walls of high aspect ratio structures and causes surface damage.
Advantages of Hydrazine Gas
- Highly reactive, enabling thermal ALD at much less than 400°C
- No line of sight required, providing uniform films on high aspect ratio structures
- No oxygen or carbon, eliminating contamination
- Fewer device defects
- Better electrical performance
Low Resistivity
Thermal ALD of TiN below 400°C with NH3/TiCl4 is problematic as Chlorine content increases and resistivity properties escalate. Use of RASIRC BRUTE® Hydrazine has been shown to yield resistivity far lower that ammonia at 400°C and nearly 5x lower at 300°C (Kummel).
Low Temperature HAR Deposition
Recent studies have shown that RASIRC BRUTE Hydrazine is capable of depositing high quality SiN down to temperatures of 320°C with good uniformity and conformality. Process optimization is underway to achieve density and Wet Etch Rates that approach those of high temperature SiN grown at 630°C with ammonia.
Crystalline Aluminum Nitride Deposition
Achieve crystalline Aluminum Nitride deposition with minimal oxygen contamination.
Processes to grow crystalline heat-spreading layers at low temperatures (≤400C) are of interest for several applications. Potential candidates for heat spreaders include diamond, hexagonal boron nitride (h-BN), aluminum nitride (AlN), and gallium nitride (GaN). AlN and GaN have already been reportedly grown at sufficiently low temperatures for widespread implementation.
See Latest Research on Nitrides.
Latest News
Low temperature Aluminium Nitride Deposition: Comparing Hydrazine and Ammonia
Aswin L.N. Kondusamy, Su Min Hwang, Zhiyang Qin, Antonio T. Lucero, Xin Meng, Dan Alvarez Jr., Jeff Spiegelman, Jiyoung Kim
HYDRAZINE 2019
ALD TiN Evaluation Using BRUTE Hydrazine
Electronics Technology Dept., Tsukuba Laboratories, Research & Development Div., RASIRC and Taiyo Nippon Sanso
HYDRAZINE 2019
BRUTE Hydrazine for Low Temperature Metal-Nitride ALD: Low Resistivity and Oxygen-Free Films Enabled by Ultra-High Purity
Daniel Alvarez and Jeffrey Spiegelman
BRUTE HYDRAZINE 2017
BRUTE Hydrazine Datasheet
PUBLISHED JULY 2018
RASIRC BRUTE Hydrazine delivers waterfree hydrazine (N2H4) gas into atomic layer deposition (ALD) processes in a repeatable method. BRUTE Hydrazine includes a vaporizer pre-loaded with hydrazine and a proprietary solvent. BRUTE Hydrazine can be used for a variety of metal nitride deposition processes at temperatures below 400°C.
RASIRC Low Temperature ALD of Silicon and Metal Nitrides
PUBLISHED ON JULY 27TH 2018
RASIRC in collaboration with The University of Texas, Dallas has recently developed a low temperature thermal ALD process using the standard silicon precursor in CVD, HCDS and their new hydrazine formulation for a liquid source anhydrous hydrazine in a proprietary solvent.
BRUTE Hydrazine for Low Temperature Metal-Nitride ALD: Low Resistivity and Oxygen-Free Films Enabled by Ultra-High Purity
PUBLISHED IN 2017
Recent research showed that hydrazine can be purified and delivered safely for low temperature ALD. RASIRC developed a unique metal-oxide based purification material that can purify the hydrazine formulation down to levels suitable for semiconductor manufacturing. A specialty delivery system improves overall safety.
RASIRC products generate and deliver water vapor, hydrogen peroxide and hydrazine gas in controlled, repeatable concentrations to critical processes.
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