Silicon is currently the most important element semiconductor material, used in semiconductor integrated circuits, diodes, epitaxial wafer substrates, solar cells and other fields, it's the basic material of the electronics industry. Thermal oxidation is an important process in silicon technology. Silicon reacts with gases containing oxidizing substances, such as water vapor and oxygen, at high temperatures to produce a dense silicon dioxide (SiO2) insulating film on the surface of the silicon wafer. It has stable chemical properties and is widely used in the manufacture of integrated circuits.

Recomended Products:

Silicon wafer CZ (Czochralski)

Diameter: 2 inch   |  3 inch   |  4 inch   |  6 inch   |  8 inch

Type: N type (Phosphorous, Antimony, Arsenic doped)   |  P type (Boron doped)

Resistivity: 0.001-0.01 ohm.cm   |  1-10 ohm.cm

Orientation: <100>   |  <111>   |  <110> 

Silicon wafer FZ (Float-Zone)

Diameter: 2 inch   |  3 inch   |  4 inch   |  6 inch   |  8 inch

Type:  un-doped

Resistivity: >5000 Ω·cm

Orientation: <100>   |  <111>   |  <110> 

Silicon dioxide wafer

Diameter: 2 inch, 4 inch, 6 inch

Thickness of dioxidate: 20 - 2000 nm

Polish: SSP  |  DSP

dioxide: Single sided dioxide  |  Double sided dioxide

More details please download <catalogue> and contact us by email...

Properties of Silicon

Silicon is hard and brittle (Mohs 7.0); band gap 1.12eV; absorption of light is in the infrared band, with high emissivity and refractive index (3.42); silicon has obvious thermal conductivity and thermal expansion properties (linear expansion coefficient 2.6*10^-6 /K), it has a large surface tension coefficient (surface tension of 720 dyn /cm); silicon has no ductility at room temperature, and it has obvious shaping at temperatures above 800 degrees, Plastic deformation is easy to occur under the effect of stress. The tensile strength of silicon is greater than that of stress reduction, and it is easy to produce bending and warping during processing.

The chemical properties of silicon are relatively stable, it exists in the form of SiO2 and silicate at room temperature. It is easy to react with mixed acids and active alkalis at room temperature; it is chemically active at high temperatures (easy to react with Cl2, O2, N2) ,  it is easy to form silicon compounds with the molten metal such as Mg / Cu / Fe / Ti / W / Mo, and easy to have substitution reaction with Cu2+ / Pb2+ / Ag+ / Hg+ and other metal.

Single-crystal silicon has the physical properties of metalloids and has weaker conductivity. Its conductivity increases with increasing temperature, so it has significant semiconductivity. Ultra-pure single-crystal silicon is an intrinsic semiconductor, doping a certain amount of electrical impurities (dopants) in ultra-pure single-crystal silicon can control the conductivity type and resistivity of single-crystal silicon. Trace group IIIA elements such as B / Al / Ga / In can increase the  conductivity to form a p-type silicon semiconductor; if doped with trace group V elements such as P / As / Sb can also increase the conductivity to form n-type silicon semiconductor.

The silicon single crystal is a cubic crystal structure, the atomic density on the crystal plane decreases in the order of 111> 110> 100, so the diffusion rate and corrosion rate increase in the direction of 111 <110 <100. Different crystal planes and crystal orientations have different properties. The microelectronic process is based on different product characteristics and uses silicon wafers with different crystal planes as substrate materials. The orientation of <100> and <110> are the most widely used in MEMS. The atomic surface density in the <111> direction is high, and this surface is relatively strong and is more suitable for high-power device. Etching on the <110> silicon wafer to make the {111} plane perpendicular to the substrate can provide a large-area, high-quality optical surface, it's widely used in the optical field.

At present, the main technologies for the preparation of single crystal silicon are the Czochralski method (CZ) and the Float-Zone method (FZ). The Czochralski process has large feeding volume, it's easy to adjust the thermal field, to obtain good radial and axial temperature gradients, so the CZ technology can prepare single crystals with large-diameter and good integrity, it's easy to obtain dislocation-free single crystals, and it can reduce the density of micro defects. The single crystal silicon grown by the Czochralski method is mainly used for semiconductor integrated circuits, diodes, epitaxial wafer substrates, and solar cells. The FZ technology is particularly suitable for preparing high-purity silicon single crystals, because there is no crucible contamination during the process, and the crystal can be purified for many times. In addition, the silicon single crystal prepared by the FZ technology has low oxygen and carbon contents and low carrier concentration, it is suitable for preparing high resistance silicon single crystals. The FZ single crystal silicon is mainly used in the field of high-voltage high-power controllable rectifier devices.

Silicon wafer oxidation technology

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 tetrahedrons composed of Si-O atom. Silicon is a semiconductor material, and silicon dioxide is a good insulating material with extremely stable chemical properties, it's very 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.