Question: Are the thermal oxides on silicon substrates? Also, what is the difference between wet and dry thermal oxides?
Answser: Wet Thermal Oxide uses steam and Dry Thermal Oxide using Oxygen.
By default Wet and Dry Thermal Oxidation is grown on both sides of the wafer. But if you need to grow oxide on just one side, usually the polished side, then dry oxide is an option. Dry oxididation is also the only option if you need very thin oxide layer. Dry thermal oxide is more expensive because the method uses molecular oxygen instead of pure steam to create the oxide layer.
Wet Thermal Oxide wet oxidation on silicon uses wafer vapor that grows on the silicon surface. Wet oxide layer thickness range from 0.12 to 2.4µm, or even up to 20µm in some cases!
Dry Thermal Oxide, dry oxidation is grown in the absence of wafer vapor, this yields a more dense Oxide layer but only layers from 10 to 300nm are practical. The Oxide layer is a thermally grown SiO2 layer, grown by actually oxidizing the Silicon atoms on the Silicon wafer surface. Chlorinated DRY Thermal Oxide is grown with the exclusion of wafer and any hydrocarbon contaminants. It is the ultimate electrical insulator. 10 to 300nm is possible.
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Refractive index of WET and DRY Thermal Oxide are not measurably different.
Leakage current is less and dielectric strength is higher for DRY than for WET Thermal Oxide.
At very low thicknesses, less than 100nm, DRY Oxide thickness can be controlled more precisely because it grows slower than WET Thermal Oxide.
Dry oxidation vs wet oxidation. The Oxide layer is a thermally grown SiO2 layer, grown by actually oxidizing the Silicon atoms on the Silicon wafer surface. WET Thermal Oxide, grown with the help of wafer vapor, yields Oxide layer thickness from from 0.12 to to 10µm on special order. DRY Thermal Oxide, grown in the absence of wafer vapor, yields a more dense Oxide layer but only layers from 10 to 300nm are practical. Chlorinated DRY Thermal Oxide is grown with the exclusion of wafer and any hydrocarbon contaminants. It is the ultimate electrical insulator. 10 to 300nm is possible.
The quality of the thicker oxide should be the same as Dry Thermal Oxidiation.
There are other SiO2 layers deposited (rather than grown) on Silicon wafers, by CVD or sputtering or Electron Beam Evaporation. These have other morphological properties, but none of them are as uniform and dense as Thermal Oxide, and they are not used in MOSFET manufacture.
We provide wet thermal oxide thicknesses up to 20um. Thicker oxide layers is great for Silicon on Insulator (SOI) wave guides technoology.
Thick Thermal Oxide is also widely used in the Chemical Mechanical Polishing (CMP) industry. Our 4um -6um Thermal Oxide on silicon wafers has been perfected as a consumable for breaking in CMP tools and polishing pads. These Silicon wafers can be reclaimed after use by stripping and re-growing the Thermal Oxide layer providing maximum material utilization.
Fast leadtimes and small quantities is what we specialize in, but larger volumes are no problem!
Unlike wet thermal oxide, dry thermal oxide can be grown on just one side of the wafer. The oxide is optimized for wafers requiring minimal thermal processing. Dry thermal oxide s often used during the semiconductor manufacturing process to form intra-metal dielectric stacks. Dry oxide is also used in MEMS and surface micro-machining processes. Our PECVD oxide films offer you greater process flexibility and can be combined with many of our other films including PECVD nitride, LPCVD nitride, and PVD metals.
For metal electrode’s it is dependent on the design. Dry thermal oxide is smoother due to it’s slower growth rate, and is sometimes preferred by researcher’s for metal patterning for this reason. However, dry thermal cannot be grown as thick as wet thermal oxide.
Researchers prefer our dry oxide coated silicon wafers to block any electrical leakage between the metal structure we will build on top and silicon, but also keep SiO2 thin.
UniversityWafer, Inc. offered
Item Qty. Description
GW65. 10/25 Silicon wafers, per SEMI Prime, OxP/EOx 4"Ø×525±25µm,
TTV<10µm, Bow<40µm, Warp<40µm,
One-side-polished, back-side Alkaline etched (both with oxide),
Dry thermal oxide: 200±14nm,
SEMI Flats (two),
Sealed in Empak or equivalent cassette.
Please send us the specs and quantity so we may quote you.
Scientists have used UniversityWafer, Inc's dry thermal oxide on Silicon-on-Insualtor Wafers for this research.
Pelase contact us for a quote.