Fiedler Holger, Gupta Prasanth, Kennedy John, Markwitz Andreas
National Isotope Centre, GNS Science, Lower Hutt, New Zealand.
Rev Sci Instrum. 2018 Dec;89(12):123305. doi: 10.1063/1.5048949.
Modern computing technology is based on silicon. To date, a cost-effective and easy to implement method to obtain isotopically pure silicon is highly desirable for attaining efficient heat dissipation in microelectronic devices and for hosting spin qubits in quantum computing. We propose that it is possible to use a Si ion beam to obtain an isotopically pure near-surface region in wafer silicon. However, this requires a highly stable, high current, and isotopically pure Si ion beam. This work presents and discusses the instrumentation details and experimental parameters involved in generating this required ion beam. Silane is used as the precursor gas and is decomposed in a Penning ion source to generate a Si ion beam. The influence of key ion source parameters such as the gas flow rate, magnetic field strength, and anode voltage is presented. An isotopically pure Si ion beam with 10 ± 0.5 A current on the target is obtained at the GNS Science 40 kV ion implanter. The beam was observed to be stable for at least 8 h and contains less than 700 ppm of other Si isotopes. This high current and high purity provides opportunities to explore efficient modification of the isotopic distribution in a native Si substrate at ambient temperature. The results highlight opportunities offered by using Penning ion source based low energy ion implanters for the synthesis of isotopically modified Si surface regions-a technique also applicable to other materials such as diamonds and diamond-like carbon.
现代计算技术基于硅。迄今为止，对于在微电子器件中实现高效散热以及在量子计算中承载自旋量子比特而言，一种经济高效且易于实施的获取同位素纯硅的方法是非常必要的。我们提出，可以使用硅离子束在晶圆硅中获得同位素纯的近表面区域。然而，这需要一个高度稳定、高电流且同位素纯的硅离子束。本文介绍并讨论了产生这种所需离子束所涉及的仪器细节和实验参数。硅烷用作前驱体气体，并在潘宁离子源中分解以产生硅离子束。文中给出了关键离子源参数（如气体流速、磁场强度和阳极电压）的影响。在GNS科学40 kV离子注入机上，在靶材上获得了电流为10±0.5 A的同位素纯硅离子束。观察到该束流至少稳定8小时，且其他硅同位素含量低于700 ppm。这种高电流和高纯度为在室温下探索对天然硅衬底中同位素分布的有效改性提供了机会。结果突出了使用基于潘宁离子源的低能离子注入机来合成同位素改性硅表面区域所带来的机遇——该技术也适用于其他材料，如钻石和类金刚石碳。
