Purity is an important indicator of quartz glass, which has a great influence on physical and chemical properties and performance, such as devitrification, high temperature strength, softening point, light transmission, thermal stability, chemical stability, radiation resistance, fluorescence characteristics, etc.; in addition, Quartz glass used in the semiconductor industry has more stringent requirements for purity, and a small amount of impurities will have a serious impact on the electrical properties, lifespan and integration of semiconductor materials. Since the purity of semiconductor materials is required to be controlled below the ppb order, the quartz glass should be controlled at the ppm order to meet the needs of the semiconductor industry. The segregation coefficient of B is close to 1, the most difficult to remove, and it is one of the most harmful impurities. Cu, Fe, Ti, etc. affect the minority carrier lifetime of semiconductors, while K, Na, and Li are harmful impurities that produce micro-defects in single crystal materials.
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Lon Diffusion and Air Permeability

The structure of quartz glass is very relaxed, and even at high temperatures, it allows certain gas ions to diffuse through the network, and sodium ions diffuse the fastest. This performance of quartz glass is particularly important for users. For example, when quartz glass is used as a high-temperature container or diffusion tube in the semiconductor industry, due to the semiconductor material

Quartz Glass

The material requires a high degree of purity, so the refractory material that is in contact with the quartz glass as the furnace lining must undergo high temperature and cleaning in advance to remove potassium, sodium and other alkaline impurities before it can be put into the quartz glass for use. The diffusion coefficient of various ions in quartz glass.

Electrical Characteristics

Quartz glass has high dielectric strength and very low conductivity, that is, it can still maintain high dielectric strength and resistance under high temperature, high pressure and high frequency, and there is almost no dielectric loss in the applied frequency band. Therefore, quartz glass is an excellent high-temperature dielectric insulating material. At normal temperature, its resistance is equivalent to 10 times that of ordinary glass, the dielectric loss to all frequencies is very small, and the insulation withstand voltage strength is high.

Thermal Performance

The thermal expansion coefficient of quartz glass is small, 5.5×10-7/℃, which is only 1/12~1/20 of ordinary glass. The standard stipulates that the sample should be burned to 1200℃ and then quickly thrown into cold water. Repeating more than three times is not allowed Burst. Quartz glass can be made into a material with zero expansion coefficient after adding an appropriate amount of titanium, and it has been used in laser technology, astronomy and cutting-edge technology.

Mechanical Behavior

The mechanical properties of quartz glass are better than hard glass and ceramics, but the brittleness is worse. The theoretical calculated strength of quartz glass is very high, about 24×103 MPa, but the actual measured strength is dozens of times lower than this value. The strength of quartz glass increases as the temperature rises, and reaches a maximum when it is close to the annealing temperature. The shear modulus, Young's modulus, damping, Poisson's ratio, and damage modulus of quartz glass generally increase with increasing temperature, while hardness decreases with increasing temperature.