The advancing miniaturisation of silicon chips is increasing demand for high-performance, cost-effective and highly efficient silicon wafers, which are considered essential components for highly integrated circuits. Derbali and Ezzaouia reported [10] of thermal SiO 2 films, which are thermally grown ultra-thin layers of Si O 2 on silicone wafers. Oxidation at high temperatures allows for a slight diffusion of oxygen through silicon dioxide. For the oxide to grow, silicon must be consumed at a high temperature, such as 1,000 degrees Celsius. [Sources: 2, 8, 9]
For practical applications, it is not necessary to calculate the thickness of the growing oxide layer using the kinetic model described above. By applying thinning oxide layers, further growth of the oxide layer can be prevented before additional oxidizing agents can penetrate the wafer. [Sources: 1, 4]
Ideally, a high-sound material would be deposited and electron microscopy (TEM) could measure the thickness of the oxide layer and its thickness in relation to the surface. Today, however, most researchers agree that there is a need for a higher k-material in the semiconductor industry. Providing the desired component performance in terms of performance, thermal conductivity, energy efficiency and thermal stability is critical for the silicon wafer industry to achieve its goal of producing smaller and smaller components. [Sources: 4, 8]
Although it is possible to remove the silicon dioxide layer with a high k - material (e.g. silicon oxide), it does not adhere well to the bare silicon underneath. Thermal oxidation can also cause stacking defects in the substrate, which are structural defects in the silicon lattice. [Sources: 4, 6]
Thermal oxide layers are produced by heating a silicon wafer in a controlled environment, and the use of thermal oxide wafers has increased in recent years due to their high thermal efficiency and their ability to be used during the dry oxidation process. The achemic Oxidea layer is added to the silicone wafer to speed up the oxidation process, achieve more consistent results and avoid air pollution. Athermal oxidation layers generally refer to an oxide layer that is formed after the silicon wafers are heated in air, a more oxidizing environment. Thermo oxide layers can also form when the silicones are heated to a temperature of more than 1,000 degrees Celsius. (3,500 degrees Fahrenheit) in controlled environments. [Sources: 1, 4]
Thermal oxide layers are formed after the original oxide layer, which can be a chemical oxide layer or an achemic oxide layer or a combination of both. The chemical oxide layer is generally better suited for the process. [Sources: 4]
The term used here, the initial oxide layer, means that there is a starting and original silicon oxide layer on the wafer. [Sources: 4]
Thermal oxidation can be applied to various materials, but silicon dioxide is most commonly produced. The abbreviation LOCOS stands for the oxidation of a selective area of the wafer or the thermal oxidation of silicon oxide in a thermal environment. [Sources: 0, 1]
The thermal oxidation variant produces a chemical vapor separation of the oxide, which leads to the formation of a thin nitride layer on the surface of the silicon wafer. Since oxidation is an addition process, the oxides grown on this nitrite layer can be used to push the nitride edge upwards, while the cultivated oxide is thicker than any silicon consumed. The ratio of grown dioxide to used silicon oxide in a thermal environment is 2: 27, which means that the dioxide grows about 1.5 times faster than that of silicon dioxide. [Sources: 0, 1, 3]
In addition, the existence of hydrogen chloride will also enable the integration of chlorine atoms into the oxide film and enable them to bond to the silicon-silicon oxide interface. In successive oxidation, other oxygen atoms must be diffused through the dioxide layer to react with silicon crystals, and other oxidizing agents must diffuse through it to form an oxide layer. In the thermal oxidation variant, however, as the oxidation rate increases and the surface of the oxide layer is surpassed by the reacting silicon, these oxidizers must diffuse away from the wafer and form a thin nitride layer on the surface of silicon wafers. [Sources: 1, 3]
Oxygen in silicon oxygen, oxygen can be found in silicon wafers at concentrations less than 1,000 ppm, and in moderate concentrations (1017 cm3) oxygen improves the mechanical properties of silicon in the wafer. N - type dopant effects due to excess oxygen on silicon, but can also cause problems with the thermal oxidation of silicon. [Sources: 5]
The growth rate of oxides is very fast, but can be slowed down if oxygen is scattered before it reaches the silicon substrate. Oxygen gas diffuses, and oxygen reacts with the surface of the wafer to form silicon dioxide, which brings it into a gaseous state. The diffusion of dopates is the slowest of all oxides on silicon, so the thickness of the oxides must be monitored to avoid inversion on lightly doped substrates. [Sources: 3, 6]
The current process can be used to produce a silicon oxide layer of a known thickness. Prime wafers or Prime denotes the highest possible quality of silicon wafers, for which there are, however, a variety of prime numbers. It can use a combination of removing the original oxide layers and etching the chemical oxide layer that grows later to create a thinned oxide layer. [Sources: 4, 7]
Sources:
[0]: https://en.wikipedia.org/wiki/Thermal_oxidation
[1]: https://link.springer.com/10.1007/978-0-387-48998-8_1173
[2]: https://www.pnas.org/content/113/42/11682
[3]: https://www.halbleiter.org/en/oxidation/oxidation/
[4]: https://www.google.com.gi/patents/US20060177987
[7]: https://cleanroom.byu.edu/ew_wafer_specs
[8]: https://www.intechopen.com/books/crystalline-silicon-properties-and-uses/study-of-sio2-si-interface-by-surface-techniques
[9]: https://www.hindawi.com/journals/ijp/2017/9503857/