The Fabrication Stuty Of High Precision And High Stability Of Crsi Thin Film Resistor

With the development of the modern electronic technology, thin-film meterial is more widely used, and it stimulates and promotes the fabrication process of thin-film technology greatly. High-precision thin film resistors have been widely used in monolithic analog integrated circuits and hybrid integrated circuits, especially in the high-precision analog integrated circuits. In this dissertation, the author select Chromium Silicon-a ceramic film as the research object. First of all, the author introduce briefly the application of CrSi thin-film resistors as well as the study in China and abroad, then describe two kinds of vacuum evaporation and sputter fabrication process of thin-film technology. Secondly, the author make use of Varian's XM-90 DC magnetion sputtering system to study on different substrates, reactive sputtering gas, film thickness, vacuum annealing, passivating layer, to focus on optimizing sputtering conditions and annealing process conditions and to initiate the study at the drift characteristic of the contact resistance and laser trimming of the CrSi thin-film resistors. Then the author describes some common parameters such as temperature coefficient, resistance tolerance, track coefficient, voltage coefficient and so on. Finally, a systematic analysis of the CrSi thin-film resistors using experimental data is made to compare with the various parameters with the advanced foreign technology.Through a mount of experiments, the author found that different substrate materials have less effect on the sheet resistance of Cr-Si thin film. With Ar and reaction gas flow (such as Nitrogen or Oxygen) increase, sheet resistance of CrSi thin film gradually increases. At the same time, sputtering and annealing process conditions have been optimized through a large number of experiments. Then the author obtain the optimal annealing conditions:120min, 460℃, N₂:O₂=3.5L:1.5L. Consequently, the temperature coefficient of CrSi thin film reduces to±10ppm/℃, and the stability has been greatly enhanced. Passivated layer lays little effect on the resistance of CrSi thin-film resistors. The drift characteristic is more worse when laser trimming parts are more. The parameters of CrSi thin-film resistors prepared by CETC 24 are similar to them abroad except the resistance tolerance.The temperature coefficient of CrSi resistor has been down to±10ppm/℃owing to the optimization of sputtering and annealing conditions, and the stability has been greatly improved. This lays a solid foundation on the application of high-precision analog integrated circuits.