Absence of free carriers in silicon nanocrystals grown from phosphorus- and boron-doped silicon-rich oxide and oxynitride

作者：Hiller Daniel^*; Lopez Vidrier Julian; Nomoto Keita; Wahl Michael; Bock Wolfgang; Chlouba Tomas; Trojanek Frantisek; Gutsch Sebastian; Zacharias Margit; Konig Dirk; Maly Petr; Kopnarski Michael

来源：Beilstein Journal of Nanotechnology, 2018, 9: 1501-1511.

DOI：10.3762/bjnano.9.141

• atom probe tomography
• doping
• photoluminescence
• silicon nanocrystals
• transient transmission

Phosphorus- and boron-doped silicon nanocrystals (Si NCs) embedded in silicon oxide matrix can be fabricated by plasma-enhanced chemical vapour deposition (PECVD). Conventionally, SiH4 and N2O are used as precursor gasses, which inevitably leads to the incorporation of approximate to 10 atom % nitrogen, rendering the matrix a silicon oxynitride. Alternatively, SiH4 and O-2 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 (I-V) 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.

• 出版日期2018-5-18