论文标题
离子梁辅助氮化钛薄膜的溅射
Ion-beam Assisted Sputtering of Titanium Nitride Thin Films
论文作者
论文摘要
氮化钛是许多超导器件(例如纳米线微波谐振器和光子探测器)的感兴趣材料。因此,控制具有理想特性的锡薄膜的生长非常重要。在先前关于硝化氮化物的工作,离子束辅助溅射(IBAS)在串联沉积过程中降低了氮敏感性,标称临界温度的升高。我们已经通过DC反应型磁控溅射和IBAS方法的常规方法沉积了硝酸钛的薄膜,并将其超导临界温度TC作为厚度,耐层阻力和氮流量的功能进行比较。我们通过电运和X射线衍射测量进行电气和结构表征。与常规的反应性溅射方法相比,IBAS技术表明,名义临界温度的增长10%,而33%的氮对氮流动的敏感性降低,而晶格结构的差异显着变化。此外,我们探讨了超薄膜中超导TC的行为。在高氮浓度下生长的膜的趋势跟随无序膜中平均场理论的预测,并显示出由于几何作用而导致的超导TC的抑制,而在低氮浓度下生长的氮化物膜与理论模型强烈偏离。
Titanium nitride is a material of interest for many superconducting devices such as nanowire microwave resonators and photon detectors. Thus, controlling the growth of TiN thin films with desirable properties is of high importance. In previous work on niobium nitride, ion beam-assisted sputtering (IBAS) reduced nitrogen sensitivity during deposition in tandem with an increase in nominal critical temperature. We have deposited thin films of titanium nitride by both, the conventional method of DC reactive magnetron sputtering and the IBAS method and compare their superconducting critical temperatures Tc as functions of thickness, sheet resistance, and nitrogen flow rate. We perform electrical and structural characterizations by electric transport and X-ray diffraction measurements. Compared to the conventional method of reactive sputtering, the IBAS technique has demonstrated a 10% increase in nominal critical temperature and 33% reduced sensitivity to nitrogen flow, without noticeable variation in the lattice structure. Additionally, we explore the behavior of superconducting Tc in ultra-thin films. Trends in films grown at high nitrogen concentrations follow predictions of mean-field theory in disordered films and show suppression of superconducting Tc due to geometric effects, while nitride films grown at low nitrogen concentrations strongly deviate from the theoretical models.