DEVELOPMENT OF A HETERING METHOD USING A PROPRIETARY HETER IN SILICON DIODE TECHNOLOGY

Abstract

Varicaps are semiconductor diodes that are widely used in radio electronics as a variable capacitance, the value of which is controlled by voltage. Varicaps are included in the circuits of radio receivers and wireless modules for data transmission, used in devices where frequencydependent circuits are involved. The operation of the varicap is relevant when adjusting the frequency of nodes in electrical equipment. Also, varicaps are used in frequency-setting circuits, as they allow you to quickly and easily change the operating frequency. However, it should be noted that the cost of varicaps remains relatively high, which is due to the low output of suitable devices. This is explained by the high level of reverse currents and low breakdown voltages of varicaps, which is determined by the significant dependence of the reverse characteristics of varicaps on the density of structural defects and heavy metal impurities in their active areas. The work is devoted to elucidating the causes and mechanisms of the degradation of the reverse characteristics of silicon varicaps with an ohmic contact based on nickel in the process of annealing the nickel film during the formation of the ohmic contact and determining the possibility of applying heterization operations to prevent the degradation of the reverse characteristics of the varicaps and increase the output of suitable devices. Conducted experimental studies showed that the reason for the degradation of the reverse characteristics of varicaps when forming an ohmic contact based on nickel is the penetration during the annealing of the nickel film of excess nickel atoms that were not involved in the formed NiSi silicide into the region of the volume charge of the p-n junction. The proposed technology for manufacturing varicap structures with ohmic contact based on nickel using heterization of excess nickel atoms by conducting additional low-temperature annealing of varicap structures using a ready-made «own getter» – Si – NiSi interface is considered in detail. It is shown that the developed technology for manufacturing varicap structures with the use of hetering allows to clean the active regions of varicaps from nickel atoms, which ensures a significant reduction in the level of reverse currents of varicaps and an increase in the output of suitable devices.