INNOVATION FOR NEXT GENERATION DEVICES
Low temperature oxide deposition for limited thermal budgets.
Minimal Subsurface Oxidation
Studies show that dry hydrogen peroxide exhibits self-limiting behavior on Si, SiGe and InGaAs surfaces. Anhydrous hydrogen peroxide (HOOH) readily splits into OH radicals, ensuring a high concentration of -OH groups on the surface that serves as a large diffusion barrier. It is difficult for additional HOOH to penetrate this barrier. In contrast, HOH (water) splits into -H and -OH groups on the surface, resulting in low –OH population and a poor barrier for additional water to react.
As devices shrink, transistors become smaller, making it difficult to physically and electrically isolate their structures. Aspect ratios can exceed 100:1 and structures can have a highly complex profiles. Void-free gap-fill in these structures is critical for better performance of advanced devices.
Smaller, more efficient devices require highly uniform nucleation, limited subsurface oxidation, and precise film thickness. Doped silicon channel materials are reaching their physical limits for carrier mobility.
Self-Aligned Multiple Patterning technology has been widely implemented in advanced semiconductor manufacturing processes due to the late arrival of EUV technology. As devices shrink, it is a challenge to form a conformal spacer on small 3D & HAR features. Good uniformity and excellent conformality at >20:1 AR are critical for next generation SAMP process.
For multiple patterning applications that require low flows or single wafer applications:
High Volume ALD
The Internet of Things requires low power and high performance semiconductor devices which will only be enabled through new materials and 3D architectures. These new devices must be processed at lower temperatures and without attacking metal surfaces at high throughput. As processes scale, oxidants must also be able to support to high volume ALD challenges.
Low Temperature Oxides
Next generation devices contain highly sensitive metal alloys which cannot be exposed to high temperatures. Traditional water ALD is unreactive or too slow at moderate temperatures. Methods involving ozone or oxygen plasma are overly aggressive and damage the surface. A new oxidant is needed which shows good reactivity (GPC) and deposits high quality oxides without adverse effects.
Area Selective Deposition
Bottom up fabrication with area selective deposition offers an alternative to EUV or multi-patterning. This can reduce the number of fabrication steps required by advanced lithography methods. Success depends on chemistry that will not react with protecting groups on adjacent surfaces or cause contamination in non-targeted areas.
Area Selective Deposition requires intricate monolayers be deposited on a complex nanostructure without reacting or contaminating protecting groups on adjacent surfaces. Plasma requires line of site, making deposition on complex 3D/HAR structures difficult if not impossible. Ozone will react with adjacent structures.
Repeatability of oxidant concentration is an extremely important for VCSEL fabrication. Oxidant delivery must be repeatable and reliable, which has proven to be difficult for many water vapor delivery systems. The AlGaAs aperture oxidation must be consistent from wafer-to-wafer, batch-to-batch, and tool-to-tool for quality product.
Solving Key Oxidation Challenges
Protect VCSEL structures from defects by using water vapor that is free of microdroplets and particles. Control key process parameters including water vapor temperature and flow rate so that structures such as sidewalls are not compromised.
Controlled Oxidation Rate
Oxidation rate is typically dictated by material composition, process temperature, and oxide source and concentration. Design in a water vapor delivery system with precision control of concentration, flow rate and purity.
Commitment To Quality
Membrane technology eliminates defects and uniformity problems. by using a particle-free, microdroplet-free water vapor source, high concentrations of water vapor can be repeatedly delivered.
Thermal oxidation processes use either wet or dry oxidation processes for a wide range of applications such as thermal oxidation, RTP, atomic layer deposition, and selective oxidation. Many water vaporizers generate particles. Wet oxidant sources should have tight control, generate stable and repeatable results, and be particle free. For sub-500C processes, hydrogen peroxide can be an excellent alternative for faster growth rate and denser films due to its lower steric hindrance.
See Latest Research on Oxides.
RASIRC Study Shows Hydrogen Plasma Damage Minimized By Hydrogen Peroxide Gas
PUBLISHED ON APRIL 13, 2022
Advantages of Hydrogen Peroxide in Spacer and Hard Mask ALD
Daniel Alvarez, PhD
PEROXIDIZER MARCH 2020
RASIRC Demonstrates Hydrogen Peroxide/Water Results in Highest Quality Growth and Film Characteristics for Metal-Oxide Dielectric ALD: Company shares comparative study results for ALD precursors at 236th ECS Meeting
PUBLISHED ON OCTOBER 13, 2019
RASIRC products generate and deliver water vapor, hydrogen peroxide and hydrazine gas in controlled, repeatable concentrations to critical processes.
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