蓝宝石上射频溅射沉积CeO_2外延缓冲层

GROWTH OF EPITAXIAL CeO_2 THIN FILMS ON SAPPHIRE BY RADIO-FREQUENCY SPUTTERING

研究了基片温度、溅射功率对采用射频溅射沉积在(1102)蓝宝石基片上的CeO2薄膜生长的影响。过低的沉积温度、溅射功率都会导致CeO2薄膜呈[111]取向生长。在基片温度为700~750 ℃,溅射功率为100~150 W,溅射气压为14 Pa下沉积了高质量[00l]取向的CeO2缓冲层。通过X射线衍射和原子力显微镜表征CeO2薄膜的结构和表面形貌。在最优化条件下制备的 CeO2薄膜具有优良的面内面外取向性和平整的表面。在CeO2缓冲层上制得的YBa2Cu3O7-δ(YBCO)超导薄膜为完全[00l]取向,面内取向性良好,并具有优越的电学性能,其临界转变温度(Tc)为89.5 K,临界电流密度Jc(77 K,0T)约为1.8×106 A/cm2,微波表面电阻Rs(77 K,10 GHz)大约为 0.30 mΩ。

[001-]oriented CeO_2 films were deposited on sapphire (1102) by radio-frequency sputtering. The CeO_2 films grown on (1102) sapphire with lower substrate temperature and sputtering power have [111] orientation. CeO_(2 )films with [001]orientation can be obtained at the substrate temperature range of 700 to 750 ℃, sputtering power from 100 to 150 W and sputtering gas pressure about 14 Pa. CeO_2 films were characterized by XRD and AFM (atomic force microscope). CeO_2 films prepared under the optimized conditions have excellent in-plane and out-of plane orientation, and flat surfaces. YBa_2Cu_3O_(7-δ)(YBCO) superconducting films grown on CeO_(2 )buffer layers are in [001] orientation. The YBCO film is strictly in-plane and out-of-plane epitaxial growth and has good electrical properties. The critical transform temperature (T_c) is about 89.5 K, critical current density(J_(c)) (77 K, 0 T) is 1.8×10~6 A/cm^2 and microwave surface resistance (R_(s)) (77 K,10 GHz) is about 0.3 mΩ, which well meets the requirement of the microwave device application.