MgO(111)衬底MgB2 超薄膜的制备和性质研究

利用混合物理化学气相沉积法(HPCVD)在MgO(111)衬底上制备了干净的MgB₂超导超薄膜. 在背景气体压强, 载气氢气流量以及沉积时间一定的情况下, 改变B₂H₆的流量, 制备得到不同厚度系列的MgB₂超导薄膜样品, 并测量了其超导转变温度 T_c, 临界电流密度J_c等临界参量. 该系列超导薄膜沿c轴外延生长, 表面具有良好的连接性, 且有很高的超导转变温度T_c(0) ≈ 35-38 K和很小的剩余电阻率ρ(42 K) ≈ 1.8-20.3 μΩ·cm^-1. 随着膜厚的减小而减小, 临界温度变低, 而剩余电阻率变大. 其中20 nm的样品在零磁场, 5K时的临界电流密度J_c ≈ 2.3×10⁷ A/cm². 表明了利用HPCVD在MgO(111)衬底上制备的MgB₂超薄膜有很好的性能, 预示了其在超导电子器件中广阔的应用前景.关键词：MgO(111)衬底2超薄膜')" href="#">MgB₂超薄膜混合物理化学气相沉积

Properties of MgB2 ultra-thin films fabricated on MgO(111) substrate by hybrid physical-chemical vapor deposition

We fabricate MgB₂ ultra-thin films via hybrid physics-chemical vapor deposition technique (HPCVD). Under the same background pressure, the same H₂ flow rate and the same deposition time, by changing the B₂H₆ flow rate, we fabricate a series of ultra-thin films with thickness values ranging from 10 nm to 40 nm. These films grow on MgO(111) substrate, and are all c-axis epitaxial. These films show the good connectivity, a very high T_c(0) ≈ 35-38 K and a very low residual resistivity ρ(42 K) ≈ 1.8-20.3 μΩ·cm^-1. As the thickness increases, critical transition temperature also increases and the residual resistivity decreases. The 20 nm film also shows an extremely high critical current density J_c (0 T, 5 K) ≈ 2.3×10⁷ A/cm², which indicates that the films fabricated by HPCVD are well qualified for device applications.
Keywords：MgO(111)substrate2 ultra-thin film')" href="#">MgB₂ ultra-thin filmhybrid physics-chemical vapor deposition