SPECIFIC FEATURES OF APPLICATION OF CADMIUM AS A NEUTRON-ABSORBING SCREEN WHILE DOPING SILICON IN A NUCLEAR REACTOR

The gradient of the neutron field in a nuclear reactor and the requirements for the permissible spread of the specific electrical resistance over the volume of the silicon ingot makes it necessary to develop an irradiation device. This is especially true for large silicon ingots. One of the options for reducing the gradient of the neutron flux along the height of the ingot is the use of neutron-absorbing screens in the design of the irradiation device. At the WWR-K reactor, cadmium with a natural isotopic composition is used as a neutron-absorbing screen material. The paper presents the results of a study of an irradiation device with a cadmium screen. The effect of a cadmium screen on the neutron-physical characteristics of an irradiation device for silicon doping is shown.

Research on Silicon Wafer Manufacturing Process and Physical Properties Testing Using High-Purity Polysilicon

The shape of a bare wafer is round, so it is called a wafer or a silicon wafer. It is the basis for the production of silicon semiconductor integrated circuits. The silicon wafer is cut from a large piece of semiconductor material silicon ingot. The high-purity polysilicon (its purity is up to 99.999999999%) is into a large single crystal, given the correct orientation and an appropriate amount of N-type or P-type doping, a silicon ingot is obtained through five-step crystal growth. Wafers (wafers) are then made from silicon ingots by more than eight processes. This paper investigates the single crystal silicon growth and wafer preparation process technology, and finally discusses the evolution of wafer size growth and changes in the development of the semiconductor industry chain.