Analysis of I/sub c/ spreads in interface engineered junctions
Analysis of I/sub c/ spreads in interface engineered junctions
复制标题
接口工程连接点中 I/sub c/ 分布的分析
DOI：
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发表时间：
2001
期刊：
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通讯作者：
T. Nagano
中科院分区：
文献类型：
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作者：
J. Yoshida;S. Inoue;H. Sugiyama;T. Nagano
我们研究了在不同工艺条件下制造的界面工程结的电学特性，以澄清I/sub c/和R/sub n/值扩散的可能来源。我们发现，在大多数情况下，晶圆上结的I/sub c/R/sub n/值与I/sub c/的平方根成比例。结点I/sub c/和R/sub n/的分布都可以用对数正态分布函数很好地表示，它们的/spl σ /值相差2倍。这些结果表明，结中的库珀对和准粒子通过不同的输运通道进行转移，即前者为直接隧道，后者为共振隧道，并且结间隧道势垒厚度的变化主导了I/sub c/和R/sub n/值的扩散。相反，在不同条件下加工的结之间，I/sub c/R/sub n/和I/sub c/之间没有普遍的标度关系。这表明由于工艺条件引起的I/sub - c/变化不是由简单的屏障厚度变化引起的。
We have investigated the electrical properties of interface engineered junctions fabricated under various process conditions to clarify the possible origin of the spreads in I/sub c/ and R/sub n/ values. We found that in most cases, the I/sub c/R/sub n/, values of junctions on a wafer scaled with the square root of I/sub c/. The distribution of both the junction I/sub c/ and R/sub n/ were expressed well by the log-normal distribution function with their /spl sigma/ values being different by a factor of two. These results indicate that Cooper pairs and quasiparticles in the junctions transfer through different transport channels, i.e., direct tunneling for the former and resonant tunneling for the latter, and that a variation in the tunnel barrier thickness among junctions dominates the spreads in the I/sub c/ and R/sub n/ values. In contrast, we could not observe a universal scaling relation between I/sub c/R/sub n/, and I/sub c/ among junctions processed under different conditions. This indicates that the I/sub c/ variation due to process conditions originates from something other than a simple barrier-thickness variation.