Improvements in Fabrication Process for Nb-Based Single Flux Quantum Circuits in Japan
Improvements in Fabrication Process for Nb-Based Single Flux Quantum Circuits in Japan
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日本铌基单通量量子电路制造工艺的改进
DOI：
10.1093/ietele/e91-c.3.318
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
T. Satoh
中科院分区：
文献类型：
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作者：
M. Hidaka;S. Nagasawa;K. Hinode;T. Satoh
我们在一个日本政府项目中开发了一种基于铌的单通量量子（SFQ）电路制造工艺，该项目于2002年9月开始，2007年3月结束。我们的传统工艺，称为标准工艺（SDP），通过对所有晶圆的所有工艺步骤和常规工艺检查进行了改进。经过改进的SDP，晶圆产量从50%大幅增加到90%以上。我们还开发了一种新的SFQ电路制造工艺，称为先进工艺（ADP）。ADP的规格为9个平面化Nb层，最小约瑟夫森结（Josephson junction， JJ）尺寸1×1μm，线宽0.8μm， JJ临界电流密度10kA/cm2, 2.4Ω Mo片电阻，垂直堆叠超导接触孔。我们利用ADP制作了一个8位SFQ移位寄存器、一个百万SQUID阵列和一个16kbit RAM。移位寄存器工作到120GHz，在一百万SQUID阵列中没有检测到短路或开路。我们通过16 kbit RAM和比SDP高5.7倍的集成度确认了正确的内存操作。
We developed an Nb-based fabrication process for single flux quantum (SFQ) circuits in a Japanese government project that began in September 2002 and ended in March 2007. Our conventional process, called the Standard Process (SDP), was improved by overhauling all the process steps and routine process checks for all wafers. Wafer yield with the improved SDP dramatically increased from 50% to over 90%. We also developed a new fabrication process for SFQ circuits, called the Advanced Process (ADP). The specifications for ADP are nine planarized Nb layers, a minimum Josephson junction (JJ) size of 1×1μm, a line width of 0.8μm, a JJ critical current density of 10kA/cm2, a 2.4Ω Mo sheet resistance, and vertically stacked superconductive contact holes. We fabricated an eight-bit SFQ shift register, a one million SQUID array and a 16-kbit RAM by using the ADP. The shift register was operated up to 120GHz and no short or open circuits were detected in the one million SQUID array. We confirmed correct memory operations by the 16-kbit RAM and a 5.7 times greater integration level compared to that possible with the SDP.
大规模SFQ数字电路系统的误码率测试
DOI：
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发表时间：
2005
期刊：
IEEE Trans.Appl.Supercond. (印刷中)
影响因子：
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作者：
K.Fujiwara;N.Nakajima;T.Nishigai;M.Ito;N.Yoshikawa;A.Fujimaki;H.Terai;S.Yorozu
通讯作者：
S.Yorozu