Silicon Thermal Oxide Wafers: Everything you should know before initiating your research
Among semiconductor technology, silicon thermal oxide wafer are mainly used as dielectric material and more recently, they are integrated in Micro Electro Mechanical Systems devices. The simplest method to fabricate silicon oxide layers on silicon wafers is to oxidize silicon with oxygen.
Silicon Thermal Oxide Wafer
Dry & Wet thermal oxidation – Silicon Wafer
The growth of a SiO2 thermal oxidewafer on a silicon surface can be carried out via high dry or wet oxidation processes. In both the cases, silicon reacts with oxygen leading to moving interface towards the substrate.
Silicon wafers are supplied from 2 to 6 inches with:
- Dry silicon wafer thin films from 20 nm to 300 nm
- Roughness less than 3 Angstroms RMS
- Wet thermal oxide from 50 nm up to 2 nm
Dry oxidation typically takes place at temperatures from 850 degree Celsius to 1200 degree Celsius and it demonstrates low growth rates. It allows a very good thickness uniformity as well as purity. Therefore, this is the preferred way to generate high-quality thin silicon oxide layers. Thicker oxide layers are generally produced by wet oxidation where the growth rate is considerably increased.
Silicon wafers is the most common material and extensively used for a variety of high tech industries, including integrated circuits, detector or sensor devices, MEMS fabrication, opto-electric equipment or tools, and last but not the least solar cells.
How is thermal oxide applied to silicon wafers?
- Grown dry oxidation- by default dry oxide is grown-up on just one side of the wafers. This is ideal for very thin oxide layers.
- Wet Oxidation grown-Wave guides technology and silicon on insulator wafers can greatly gain from thick thermal oxide layers.
- Deposited CVD- When you cannot oxidize silicone, then you can utilize chemical vapour deposition to deposit the oxide on top of your substrate.
Applications for oxidized Silicon wafers
The procedure of oxidizing silicon wafers includes a diversity of specific techniques that use heat to create a layer of silicon dioxide on the top most part of the pure silicone that comprises the majority of the wafers.
Thermal oxidation is most useful for applications that necessitate a low density of electrical charge at the interface between the silicone and SiO2 layers. ICs with multiple levels require vapour phase oxidation to create SiO2 layer on top of the metal layer, although this process produces an oxide layer of lower quality than thermal oxidation.
Thermal Oxidation process for Silicon Thermal oxide wafers
- The thermal oxidation of silicon begins by placing the silicon wafers in a quartz rack, commonly called as a boat, which is heated in a quartz thermal oxidation furnace
- Oxygen or steam is introduced into the thermal oxidation furnace, depending on the category of oxidation being performed
Oxygen from these gases then diffuses from the surface of the substrate through the oxide layer to the silicon layer; the symphony and depth of the oxidation layer may be precisely controlled by parameters such as time, temperature, pressure as well as gas concentration.
