Hiller Daniel, López-Vidrier Julian, Nomoto Keita, Wahl Michael, Bock Wolfgang, Chlouba Tomáš, Trojánek František, Gutsch Sebastian, Zacharias Margit, König Dirk, Malý Petr, Kopnarski Michael
Research School of Engineering, Australian National University (ANU), Canberra, Australia.
Laboratory for Nanotechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany.
Beilstein J Nanotechnol. 2018 May 18;9:1501-1511. doi: 10.3762/bjnano.9.141. eCollection 2018.
Phosphorus- and boron-doped silicon nanocrystals (Si NCs) embedded in silicon oxide matrix can be fabricated by plasma-enhanced chemical vapour deposition (PECVD). Conventionally, SiH and NO are used as precursor gasses, which inevitably leads to the incorporation of ≈10 atom % nitrogen, rendering the matrix a silicon oxynitride. Alternatively, SiH and O can be used, which allows for completely N-free silicon oxide. In this work, we investigate the properties of B- and P-incorporating Si NCs embedded in pure silicon oxide compared to silicon oxynitride by atom probe tomography (APT), low-temperature photoluminescence (PL), transient transmission (TT), and current-voltage (-) measurements. The results clearly show that no free carriers, neither from P- nor from B-doping, exist in the Si NCs, although in some configurations charge carriers can be generated by electric field ionization. The absence of free carriers in Si NCs ≤5 nm in diameter despite the presence of P- or B-atoms has severe implications for future applications of conventional impurity doping of Si in sub-10 nm technology nodes.
嵌入氧化硅基质中的磷和硼掺杂硅纳米晶体（Si NCs）可通过等离子体增强化学气相沉积（PECVD）制备。传统上，SiH和NO用作前驱体气体，这不可避免地导致掺入约10原子%的氮，使基质成为氮氧化硅。或者，可以使用SiH和O，从而得到完全不含氮的氧化硅。在这项工作中，我们通过原子探针断层扫描（APT）、低温光致发光（PL）、瞬态透射（TT）和电流-电压（I-V）测量，研究了嵌入纯氧化硅中的含硼和磷的Si NCs与氮氧化硅相比的特性。结果清楚地表明，尽管在某些配置中电荷载流子可以通过电场电离产生，但Si NCs中不存在来自磷或硼掺杂的自由载流子。对于直径≤5 nm的Si NCs，尽管存在磷或硼原子，但不存在自由载流子，这对传统的硅杂质掺杂在小于10 nm技术节点中的未来应用具有严重影响。
