中文摘要：

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,制备得到不同厚度的系列MgB2超导薄膜样品,并测量了其超导转变温度Tc,临界电流密度Jc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Tc（0）≈35—38K和很小的剩余电阻率ρ（42K）≈1.8—20.3μ.cm.随着膜厚的减小,临界温度变低,而剩余电阻率变大.其中20nm的样品在零磁场,5K时的临界电流密度Jc≈2.3×107A/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.

英文摘要：

We fabricate MgB2 ultra-thin films via hybrid physics-chemical vapor deposition technique （HPCVD）. Under the same back- ground 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 Tc（0） 35-38 K and a very low residual resistivity p（42 K） 1.8-20.3 t.cm. 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 Jc （0 T, 5 K） 2.3 x 107 Alcm2, which indicates that the films fabricated by HPCVD are well qualified for device applications.