Semiconductors are used in integrated circuits, consumer electronics, communication systems, photovoltaic power generation, lighting, high-power power conversion and other fields. For example, diodes are devices made of semiconductors. The importance of semiconductors is huge, both from a technological and economic perspective. The core units in most electronic products, such as computers, mobile phones or digital recorders, are closely related to semiconductors. Common semiconductor materials are silicon, germanium, gallium arsenide and so on. Silicon is the most influential one in the application of various semiconductor materials.
OST Photonics offer a variety of semiconductor wafers for semiconductor industry. We have a wide range of semiconductor wafers for you to choose from: Silicon wafers, Germanium wafers, GaAs wafers, SiC wafers, InP wafers, GaSb wafers, InAs wafers and GaN wafers, etc. Customized substrates are also available upon request.
Silicon reacts with gases containing oxidizing substances, such as water vapor and oxygen, at high temperatures to produce a dense silicon dioxide (SiO2) film on the surface of the silicon wafer. This is an important process in silicon technology. At present, the silicon dioxide film is generally prepared by alternating oxidation methods of dry oxygen-wet oxygen-dry oxygen. The silicon dioxide film grown by the thermal oxidation process has an amorphous glass-like structure. The basic unit of this structure is a regular tetrahedron composed of Si-O atoms. Silicon is a semiconductor material, and silicon dioxide is a good insulating material with extremely stable chemical properties, oxide wafers are widely used in integrated circuit manufacturing:
Masking impurities: Silicon dioxide masks the diffusion of impurities. In integrated circuit manufacturing, several impurities such as boron, phosphorus, arsenic, etc. diffuse in the silicon dioxide film much slower than they diffuse in silicon. Therefore, in the production of various regions of semiconductor devices (such as the source and drain regions of transistors), the most commonly used method is to first grow an oxide film on the surface of the silicon wafer, after photolithography and development, and then etch away the oxide film, and finally, impurities are selectively injected into the corresponding region through the window.
Gate oxide layer: In the manufacturing of MOS / CMOS, SiO2 is usually used as the insulating gate dielectric of the MOS transistor, that is, the gate oxide layer.
Dielectric isolation: The isolation methods in integrated circuit fabrication include PN junction isolation and dielectric isolation, and the SiO2 oxide film is commonly used as dielectric isolation. For example, the field oxygen in the CMOS process (used to isolate PMOS and NMOS transistors) is the SiO2 film used to isolate the active area of the PMOS and NMOS transistors.
Insulation medium: Silicon dioxide is a good insulator, so for the multi-layer metal wiring structure, it is used as an insulation medium between the upper and lower layers of metal to prevent short circuits between metals.
Monocrystalline silicon is a kind of silicon crystal material with fixed crystal orientation, which is generally used as the substrate of semiconductor integrated circuit and also used to make solar cell. Polycrystalline silicon is a kind of silicon crystal material without uniform fixed crystal orientation, which is generally used for solar photovoltaic power generation, or for the raw material of monocrystalline silicon. Monocrystalline silicon is a kind of excellent high-purity semiconductor material.
The purity of IC level is required to be more than 9N (99.999999%), and even 11n (99.9999999%) for zone melting monocrystalline silicon wafer. Generally, CZ and FZ are used to form long crystals, whose orientation is determined by seed crystal. Monocrystalline silicon is the most important semiconductor material, accounting for more than 90% of the semiconductor material market, which is the basic material of information technology and integrated circuit.
The Float Zone (FZ) method produces a highly pure form of silicon. The purity of the material allows for lower defect concentrations and higher resistivity levels and it is useful in high-power devices, detectors and solar applications.