Side-wall spacer passivated sub-μm Josephson junction fabrication process
Side-wall spacer passivated sub-μm Josephson junction fabrication process
复制标题
侧壁间隔钝化亚μm约瑟夫森结制造工艺
DOI：
10.1088/1361-6668/aa9411
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发表时间：
2017
影响因子：
3.6
通讯作者：
J. Hassel
中科院分区：
文献类型：
--
作者：
L. Grönberg;M. Kiviranta;V. Vesterinen;J. Lehtinen;S. Simbierowicz;J. Luomahaara;M. Prunnila;J. Hassel
我们提出了一种结构和超导隧道结的制造方法，尺寸下降到200 nm，使用i线紫外光刻。关键元件是侧壁钝化间隔结构（SWAPS），其形状为平滑的交叉线接触和低寄生电容。SWAPS结构使得能够形成具有处于或低于光刻限制线宽的尺寸的结。另一个好处是避免了非晶介电材料的过度使用，这在亚开尔文微波应用中是有利的，通常受到非线性和有损耗介电常数的困扰。我们将该结构应用于铌三层结，并提供表征结果，证明晶圆级可扩展性，以及在0.1-3.0 kA cm−2范围内的临界电流密度调谐。我们讨论的结过程中的不同应用的背景下，如SQUID磁强计和约瑟夫森参量放大器的适用性。
We present a structure and a fabrication method for superconducting tunnel junctions down to the dimensions of 200 nm using i-line UV lithography. The key element is a sidewall-passivating spacer structure (SWAPS) which is shaped for smooth crossline contacting and low parasitic capacitance. The SWAPS structure enables formation of junctions with dimensions at or below the lithography-limited linewidth. An additional benefit is avoiding the excessive use of amorphous dielectric materials which is favorable in sub-Kelvin microwave applications often plagued by nonlinear and lossy dielectrics. We apply the structure to niobium trilayer junctions, and provide characterization results yielding evidence on wafer-scale scalability, and critical current density tuning in the range of 0.1–3.0 kA cm−2. We discuss the applicability of the junction process in the context of different applications, such as SQUID magnetometers and Josephson parametric amplifiers.