Study On The Preparation Of Resistive Thin Films By Magnetron Sputtering And Black Silicon By Dry Etching

Thin films and micromachining technology are widely used in many fields,such as large scale integrated circuit,electronic components,flat panel display,information recording and storage,MEMS,sensors,solar cells,and surface modification of materials,involving civil and military fields.Thin films with low temperature coefficient of resistance are widely used in flow sensors,thin film thermoelectric converters,standard source and measurement.The rate of the thin films deposited by magnetron sputtering technology is high.Magnetron sputtering can realize the precise control of the thin film thickness,which is closely related to the temperature coefficient of resistance.Compared with low pressure chemical vapor deposition,plasma enhanced chemical vapor deposition and other coating methods,magnetron sputtering can be carried out at a lower temperature,which can avoid the influence of high temperature on the previous process.Therefore,Ni₄₅Cr₅₀Si₅thin films with different thicknesses were prepared by radio frequency magnetron sputtering,and the changes of sheet resistance and temperature coefficient of resistance after annealing were studied in this paper.Finally,the thin film of Ni₄₅Cr₅₀Si₅with temperature coefficient of resistance of1.6ppm/?was obtained.Compared with the traditional thin film of Ni Cr,the temperature coefficient of resistance decreases by an order of magnitude with the addition of Si element.Thin films with high temperature coefficient of resistance are often used in temperature measurement and infrared detection.At present,the thin film materials with high temperature coefficient of resistance generally include Pt,Ag,Al and metal oxides,etc.,but Pt is expensive,Al and Ag have small resistivity,and Al is easy to corrode.Although the temperature coefficient of resistance of metal oxides is very high,its resistivity is too large.In this paper,the thin film of Ta N were prepared by reactive magnetron sputtering with Ta as the target.The influence of the flow rate of reactive gas(N₂)on the deposition rate,sheet resistance and temperature coefficient of resistance of Ta N was studied.The temperature coefficient of resistance of Ta N thin film was-2179 ppm/?.Black silicon has high absorption rate of visible light and near infrared light,so it is often used to make light absorption films of solar cells and sensitive films of photodetectors.The conventional femtosecond laser method is high cost and low efficiency.The high pulse energy is easy to melt the silicon substrate.Alkali etching is limited by the lithography accuracy of the mask.The surface microstructure of black silicon can only reach micron level.Acid etching could introduce metal ion pollution.Therefore,this paper used O₂/SF₆dry etching process to etch monocrystalline silicon and PECVD amorphous silicon thin film,and finally prepared monocrystalline black silicon and amorphous black silicon with good surface morphology when O₂/SF₆flow ratio is 0.5.