本文選題：衰減器　切入點：TaN薄膜　出處：《電子科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：微波衰減器因其質(zhì)量輕、體積小、易集成、使用頻率高等特點而被廣泛應(yīng)用于現(xiàn)代微波通信系統(tǒng)和微波電路中。衰減器在微波系統(tǒng)中主要作用是調(diào)節(jié)輸入信號電平且不使信號發(fā)生畸變。微帶薄膜衰減器主要通過電阻性薄膜材料吸收功率轉(zhuǎn)化為熱量來實現(xiàn)衰減。Ta N薄膜作為重要的電阻性薄膜材料,具有非常重要的研究價值。本文首先研究了Ta N薄膜材料的性能,并將Ta N薄膜作為電阻材料設(shè)計了一系列不同衰減量的衰減器。本文關(guān)于微波衰減器主要做了以下三方面的研究工作:在材料方面,通過在Ta靶上放置不同面積的Ti靶來實現(xiàn)不同比例的Ti摻雜,研究了Ti摻雜比例對Ta N薄膜電阻率和電阻溫度系數(shù)(TCR)的影響。研究發(fā)現(xiàn)隨著Ti摻雜比例的增大,薄膜的電阻率逐漸增大,但薄膜的TCR也逐漸增大。當(dāng)摻雜比例達到26%時,Ta N薄膜的電阻率幾乎增加了一倍,薄膜的TCR也由未摻雜時的-45 ppm/℃增大到-214 ppm/℃;通過控制流入真空室中N2的含量來制備多層膜結(jié)構(gòu),多層膜由Ta、Ti構(gòu)成的金屬層和Ta N、Ti N構(gòu)成的氮化層組成。研究發(fā)現(xiàn)隨著Ta、Ti構(gòu)成的金屬層比例不斷增大,薄膜的電阻率逐漸減小,但薄膜的TCR也逐漸減小,當(dāng)金屬層的比例增大到67%時,薄膜的TCR由-166 ppm/℃變?yōu)?74 ppm/℃,TCR得到改善。在衰減器設(shè)計與仿真方面,根據(jù)多級衰減器級聯(lián)的思想,利用HFSS軟件設(shè)計仿真了衰減量分別為12 d B、13 d B、19 d B、20 d B(兩種)共五種衰減器。其使用頻率均為DC-15GHz,在該頻率范圍內(nèi),VSWR均小于1.25。依據(jù)電阻膜面積大小,設(shè)計12 d B衰減器和13 d B衰減器的承載功率為2W,19 d B衰減器和20 d B衰減器(兩種)的承載功率為3W。在衰減器制作與測試方面,利用磁控濺射,真空蒸發(fā)和光刻等技術(shù)在被釉Be O基片上制備了衰減器;制作測試夾具,利用矢量網(wǎng)絡(luò)分析儀測試了衰減器的微波性能,測試結(jié)果基本與設(shè)計相符。通過對各個衰減器加載1小時相應(yīng)的設(shè)計功率,測得電阻膜表面最高溫度都低于125℃,達到了設(shè)計要求。
[Abstract]:Microwave attenuator is easy to integrate because of its light weight, small volume and easy integration. It is widely used in modern microwave communication system and microwave circuit because of its high frequency. The main function of attenuator in microwave system is to adjust the input signal level without distorting the signal. As an important resistive thin film material, the attenuation can be realized by converting the absorption power of resistive thin film into heat. In this paper, the properties of Ta N thin films are studied. A series of attenuators with different attenuations are designed using Ta N thin films as resistive materials. In this paper, the microwave attenuators are studied in the following three aspects: in material, The effects of Ti doping ratio on resistivity and TCRs of Ta N thin films are studied by placing Ti targets with different areas on Ta targets. It is found that the ratio of Ti doping increases with the increase of Ti doping ratio. The resistivity of Ta-N thin films increases gradually, but the TCR of the films increases gradually. When the doping ratio reaches 26, the resistivity of Ta N thin films almost doubles, and the TCR of the films increases from -45 ppm/ 鈩，

本文編號：1630238