Y-Ba-Cu-O thin films on 3" sapphire wafers for microwave devices
Y-Ba-Cu-O thin films on 3" sapphire wafers for microwave devices
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用于微波器件的 3" 蓝宝石晶圆上的 Y-Ba-Cu-O 薄膜
DOI：
10.1109/77.919356
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
R. Schwab
中科院分区：
文献类型：
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作者：
R. Aidam;J. Geerk;G. Linker;F. Ratzel;J. Reiner;R. Schneider;R. Smithey;A. Zaitsev;E. Gaganidze;R. Schwab
外延生长的大面积YBCO薄膜是超导高频器件，如通信微带滤波器的关键。因此，通过从CeO/sub 2/缓冲的3”蓝宝石晶片的两侧上的中空圆柱形靶溅射，同时沉积c轴取向的250至500 nm厚的YBCO膜。通过在145 GHz和75 K下绘制表面电阻R/sub s/来分析横向均匀性。在整个地区，R/sub s/的值低于50 m/spl Ω/。在8.5GHz和77 K下，击穿场强大于10 mT，证明了该器件的高频功率处理能力。为了证明我们的溅射薄膜的质量相对于大面积的高频应用，简单的微带谐振器图案化的UV光刻和湿化学蚀刻。在循环功率高达1 W，非常高的空载品质因数，Q/sub 0/，高达32000在4 GHz和77 K实现。高于5 W，由于R/sub s/的场依赖性，Q/sub 0/减小。复杂结构的操作演示了3极点和7极点带通滤波器工作在77 K和2 GHz和6 GHz，分别。由黄铜调谐元件调谐的滤波器显示出小于-0.3 dB的传输损耗和大于-17 dB的反射损耗。
Epitaxially grown large area YBCO films are essential for superconducting high frequency devices, e.g. microstrip filters for telecommunications. Therefore, c-axis oriented, 250 to 500 nm thick YBCO films were simultaneously deposited by sputtering from hollow cylindrical targets on both sides of CeO/sub 2/ buffered 3" sapphire wafers. The lateral homogeneity was analyzed by mapping the surface resistance, R/sub s/, at 145 GHz and 75 K. Values of R/sub s/ below 50 m/spl Omega/ were reached over the whole area. The HF power handling capability was demonstrated by a break down field higher than 10 mT at 8.5 GHz and 77 K. In order to demonstrate the quality of our sputtered films with respect to large area high frequency applications, simple microstrip resonators were patterned by UV photo lithography and wet chemical etching. At a circulating power of up to 1 W, very high unloaded quality factors, Q/sub 0/, of up to 32000 at 4 GHz and 77 K were achieved. Above 5 W, Q/sub 0/ decreased due to the field dependence of R/sub s/. The operation of complex structures was demonstrated by 3 pole and 7 pole bandpass filters operated at 77 K and 2 GHz and 6 GHz, respectively. The filters, tuned by brass tuning elements, showed transmission losses of less than -0.3 dB and reflection losses of more than -17 dB.