Progress in industrialization of NTC series semiconductor nanometer powder technology
Progress in industrialization of NTC series semiconductor nanometer powder technology
Transition metal manganese, silicon, copper, cobalt, iron, nickel oxide consisting of semiconductor materials, is a kind of resistance value decreases with negative temperature coefficient increases with temperature (NTC) of the thermal resistance of semiconductor material, belonging to the stability and life of the best NTC resistance material, mostly ceramic oxide spinel structure. This type of material fabricated products can be widely used in industrial electronic equipment, power equipment, testing instruments, which can be used for integrated circuit of electronic circuit surge elimination, temperature detection and monitoring, precision level measurement, pressure measurement, fire alarm, meteorological sounding, switch circuit, automatic gain adjustment, also can be used for infrared detection film, aerospace microwave and laser power measurement, with a broad market prospect and strategic value. As a power NTC thermistor, it can suppress the high surge current generated in the circuit when the circuit power is switched on. The initial resistance of the NTC thermistor is large, which can restrain the excessive current in the integrated circuit, thus protecting the power circuit and the load. When the circuit enters the normal working state, the NTC thermistor causes the temperature rise of the resistor body through the current, and the resistance value drops to very small, which will not affect the normal operation of the circuit. The NTC thermistor can be considered to be automatic recovery fuse function a perfect integrated circuit, so it was widely applied to the integrated circuit, each person's daily mobile phone and computer, mobile base station, the network server must use this element, can be said to have integrated circuit, has its shadow.
Japan and the United States related enterprises to such semiconductor nano powder materials monopoly foundry sales, leading to domestic production of mobile phones and computers more than 90% of the micro type high-precision NTC resistance device semiconductor materials are from Japan and the United States enterprises, imports every year tens of billions of pieces. Traditional NTC resistor is a large size and poor precision model, which can not meet the requirements of miniaturization, high precision and high integration of large scale integrated circuit, and the related enterprises are facing pressure of industrial upgrading. Ships, aircraft and high-speed rail on the high performance and high precision miniature thermal devices, will also face the threat of foreign lock under special circumstances. To solve the localization of nano semiconductor materials for NTC miniaturization components, it has a very important role in promoting industrial upgrading and strategic significance.
Su Lihong has been engaged in the preparation, application and theoretical research of nano powder. He and the students to the domestic equipment for years of transformation, through repeated tests, the nano powder uniformity is greatly improved, the particle size distribution of deviation can achieve positive and negative 5-100 nano scale controlled, and overcome the past twenty years the world study on Preparation of nanomaterials in the universality of the problem. Through the improvement of process and equipment, nano powders can still keep good dispersibility after drying. In the detection technology, he also on how to evaluate the dispersion of nano powder, analysis, sample processing and other proprietary technology.
In the research and development of space satellite technology in China, Su Lihong's research has made breakthroughs in improving the densification of nano powder fired films. But because of the space with little dosage in order to improve the applicability of the technology, so that the general public benefit, Su Lihong for several years by changing the formulation and process development of civilian NTC thermistor applications of nano powder, the major innovation in civil transition metal oxides, manganese and copper, silicon, iron, cobalt, nickel and other two or more than two the composition of the oxide semiconductor nano powder material manufacturing technology, is a typical conversion project. The obtained powders are all nano scale, and the high uniformity of monodisperse, size and spherical morphology of NTC series semiconductor nanopowders is achieved. At present, the semiconductor nano powder made by this technology has formed six series of different resistance and heat sensitive index varieties, through cooperation with other units, has made a batch device finished sample. This is the first time in our country to use nano semiconductor powder raw materials to prepare civilian miniature high-precision NTC resistance device, China has become fully mastered the semi conductor thermal device manufacturing technology industry chain of the whole country.
