Tang K, Kim H S, Ramanayaka A N, Simons D S, Pomeroy J M
Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20740, United States of America.
National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8423, United States of America.
J Phys Commun. 2020;4(3). doi: https://doi.org/10.1088/2399-6528/ab7b33.
We report on the growth of isotopically enriched Si epitaxial films with precisely controlled enrichment levels, ranging from natural abundance ratio of 92.2% all the way to 99.99987% (0.83 × 10 mol molSi). Isotopically enriched Si is regarded as an ideal host material for semiconducting quantum computing due to the lack of Si nuclear spins. However, the detailed mechanisms for quantum decoherence and the exact level of enrichment needed for quantum computing remain unknown. Here we use hyperthermal energy ion beam deposition with silane gas to deposit epitaxial Si. We switch the mass selective magnetic field periodically to control the Si concentration. We develop a model to predict the residual Si isotope fraction based on deposition parameters and measure the deposited film using secondary ion mass spectrometry (SIMS). The measured Si concentrations show excellent agreement with the prediction, deviating on average by only 10%.
我们报告了具有精确控制富集水平的同位素富集硅外延薄膜的生长情况，其富集水平范围从天然丰度比的92.2%一直到99.99987%（0.83×10摩尔/摩尔硅）。由于硅核自旋的缺乏，同位素富集硅被视为半导体量子计算的理想主体材料。然而，量子退相干的详细机制以及量子计算所需的精确富集水平仍然未知。在这里，我们使用超热能离子束与硅烷气体沉积外延硅。我们定期切换质量选择磁场以控制硅浓度。我们开发了一个基于沉积参数预测残余硅同位素分数的模型，并使用二次离子质谱（SIMS）测量沉积薄膜。测量的硅浓度与预测结果显示出极好的一致性，平均偏差仅为10%。
