论文标题
在SI基板上制造深烟仪NBN/ALN/NBN外延连接
Fabrication of Deep-Sub-Micrometer NbN/AlN/NbN Epitaxial Junctions on a Si Substrate
论文作者
论文摘要
我们已经开发了一种用于超小型，全部epitaxial NBN Josephson连接硅（SI）底物上的新型制造过程。在SI（100）晶圆上生长了全部外皮NBN/ALN/NBN三层，并带有（200）为导向的锡缓冲层。它被电子束光刻（EBL）的约瑟夫森连接构图，以进行连接定义，然后是反应性离子蚀刻（RIE）。化学机械抛光（CMP）工艺和通过CHF $ _3 $气体在交界处电极和接线层之间形成可靠的电气接触的额外RIE。所有制造的连接连接尺寸的直径低至0.27 $ m $ m，均显示出出色的电流 - 电压特性，具有透明的间隙结构和小的亚间隙泄漏电流。使用缓冲的HF溶液在湿蚀刻过程中除去了用作基础和反电极之间绝缘体的SIO $ _2 $的介电层。我们已经确认，在移除SIO $ _2 $介电层后保持了连接的质量。
We have developed a novel fabrication process for ultra-small, full-epitaxial NbN Josephson junctions on a silicon (Si) substrate. A full-epitaxial NbN/AlN/NbN tri-layer was grown on a Si (100) wafer with a (200)-oriented TiN buffer layer. It was patterned into Josephson junctions by an electron beam lithography (EBL) for junction definition followed by a reactive ion etch (RIE). A chemical mechanical polishing (CMP) process and an additional RIE by using CHF$_3$ gas formed reliable electrical contacts between the junction counter electrodes and the wiring layer. All fabricated junctions, with a junction size down to 0.27 $μ$m in diameter, showed excellent current-voltage characteristics with a clear gap structure and a small sub-gap leakage current. The dielectric layer of SiO$_2$ that served as an insulator between base and counter electrodes was removed in a wet etching process using a buffered HF solution. We have confirmed that the quality of the junctions was maintained after the removal of the SiO$_2$ dielectric layer.
