【摘要】 报道了制备MgB2 超导薄膜的一种新方法和测量结果 .MgB2 超导薄膜的制备采用的是两步异位退火方法 ,但与现有报道的方法不同的是 ,制备硼 (B)先驱膜采用的是化学气相沉积方法 ,在 4 6 0℃温度下热分解乙硼烷 (B2 H6 )沉积的 ,然后镁 (Mg)蒸气中分别在 730℃、780℃和 830℃条件下退火 ,生成MgB2 超导薄膜 .扫描电子显微镜观察表明制备薄膜是多晶的 ,MgB2 晶粒小于 2 μm .X衍射分析发现所生长的薄膜是随机取向的 .80 0℃条件下退火生成的MgB2 超导薄膜起始转变温度和零电阻温度分别达到 35K和 2 4K .结果表明 ,采用B2 H6 热分解化学气相沉积B先驱膜的方法在优化的沉积条件和退火条件下可以制备高质量的MgB2超导薄膜 .我们这种化学气相沉积MgB2 超导薄膜方法在大面积的MgB2 超导薄膜制备方面较脉冲激光沉积方法具有优势 ,并且与现有的半导体工艺技术相兼容 ,有利用实现MgB2 超导薄膜在电子器件方面的应用 .更多还原

【Abstract】 We report a new preparation method and measurement results of surperconducting MgB 2 films. Superconduting MgB 2 films were prepared on Al 2O 3 polycrystalline substrates in a two step ex situ process. Contrary to previous reports, precusor boron thin films were deposited by chemical vapor deposition from diborane (B 2H 6) at 470℃ followed by post annealing in Mg vapor at 730℃, 780℃ and 830℃, respectively. The scanning elecetron microscope (SEM) observations reveal that the fabricated films are polycrystalline films with crystal dimensions below about 2μm and with uneven surfaces. The X diffraction patterns showed random orientated growth of MgB 2 phase and the existence of MgO and MgAl 2O 4 phases in the films. Resistance measurements show the film annealed at 830℃ reaches onset critical temperature T con of 35K and zero resistance temperature T c0 about 24K. This result confirms the possibility to sysnthesise high quality superconducting MgB 2 films by deposition of precursor boron films from B 2H 6 under optimal depositing and annealing conditions. The advantage of the method is in the preparation of large area films, and is more compatible with semiconductor technology.更多还原