Superconducting films fabricated by high-fluence Ga implantation in Si
Superconducting films fabricated by high-fluence Ga implantation in Si
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高通量硅注入Ga制备超导薄膜
DOI：
10.1103/physrevb.83.214504
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发表时间：
2011
影响因子：
3.7
通讯作者：
M. Helm
中科院分区：
文献类型：
--
作者：
J. Fiedler;V. Heera;R. Skrotzki;T. Herrmannsdörfer;M. Voelskow;A. Mücklich;S. Oswald;B. Schmidt;W. Skorupa;G. Gobsch;J. Wosnitza;M. Helm
通过30 nm的SiOcover层注入80 keV的Ga，在500 ~ 1000℃的温度范围内快速退火60 s，制备了富Ga层。2×10cmand 4×10cm的影响，导致Ga峰值浓度为8 at。%和16 %。%，被选中。采用离子通道、横截面电镜和x射线光电子能谱结合卢瑟福-后向散射光谱法研究了植入层的残余损伤和镓的分布。为了确定植入层的电学特性，进行了与温度相关的霍尔效应测量。结果表明，在高达800℃的温度下退火可形成含有随机分布的非晶团簇的多晶层。在Si/ sio界面处，观察到密集而窄的富ga团簇。在4 ×10cm时，可移动Ga的量比2×10cmand时高，Si/ sio0界面处的团簇密度增加。由于4×10cmthis的团簇密度较高，在优化的退火条件下，界面层可以在7 K以下超导，临界场超过9 T。临界电流高于1 kA/指令，因此这似乎是未来微电子应用的可能材料系统。在900℃及以上退火后，注入层为单晶，无非晶析出。
Ga-rich layers in Si were fabricated by 80 keV Ga implantation through a 30 nm SiOcover layer and subsequent rapid thermal annealing for 60 s in a temperature range between 500 °C and 1000 °C. Fluences of 2×10cmand 4×10cm, leading to Ga peak concentrations of 8 at. % and 16 at. %, are chosen. Residual damage in the implanted layers and the Ga distribution were investigated by Rutherford-backscattering spectrometry in combination with ion channeling, cross-sectional electron microscopy, and x-ray photoelectron spectroscopy. Temperature-dependent Hall-effect measurements were carried out in order to determine the electrical properties of the implanted layers. It is shown that annealing at temperatures up to 800 °C leads to the formation of polycrystalline layers containing random distributed amorphous clusters. At the Si/SiOinterface a dense and narrow band of Ga-rich clusters is observed. For 4 × 10cmthe amount of mobile Ga is higher than for 2×10cmand an increase of the cluster density at the Si/SiOinterface was found. Due to the higher cluster density for 4×10cmthis interface layer can become superconducting below 7 K with critical fields exceeding 9 T at optimized annealing conditions. Critical currents are above 1 kA/cmand therefore this seems to be a possible material system for future microelectronic applications. After annealing at 900 °C and above, the implanted layers are single crystalline and no amorphous precipitates were detected.