Comparative Evaluation of Ultrathin Mask Layers of SiO₂, SiO_xN_y and SiN_xfor Selective Area Growth of Si

Abstract

Ultrathin SiO2 and SiN x layers on Si are potential mask materials for nanoscale selective-area chemical vapor deposition (CVD) in reduced dimension. This study investigates the mask-material dependence of Si nucleation processes on these ultrathin layers. Thin layers of SiO2, SiN x and SiO x N y were formed by plasma oxidation and nitridation. They were subjected to CVD processing without exposure to air, which prevented the results from being affected by surface contamination. Incubation time for nucleation was checked by both in-line Auger electron spectroscopy (AES) and atomic force microscopy (AFM). In the case of ultrahigh vacuum CVD (UHV-CVD) at 853 K, the incubation time for nucleation decreased in the order of SiO2, SiO x N y and SiN x . In the case of flow-modulated plasma-enhanced CVD (FM-PECVD) at 473 K, Si growth did not depend on the kind of the mask material. Direct electron-beam patterning of this mask layer is briefly reported. Based on the results presented, a novel bilayer mask structure is proposed.

Effects of growth temperature on surface morphology of InP grown on patterned Si(0 0 1) substrates

“…In our experiment, SiN x mask layers were used since they were not etched by a dilute HF solution, and mask shape did not change before and after pre-cleaning process. In addition, the surface migration length on SiN x is shorter compared to that on SiO 2 for Ga, In precursors, which facilitated the formation of flat surfaces [20]. The formation of void can be also attributed to the lower growth rate of {1 1 1} facets inside void than that of (0 0 1) plane of LT InP.…”

Effects of Chemical Composition and Morphology of Substrate Surfaces on Crystallinity of Ultrathin Hydrogenated Microcrystalline Silicon Films

“…For plasma oxidation of the SiN x layer described in §3. 3,9,10) the the substrate surface is likely to play an important role. Related to this issue, we previously compared Si deposition processes on SiO 2 and SiN x surfaces for the purpose of selective-area growth.…”

“…Related to this issue, we previously compared Si deposition processes on SiO 2 and SiN x surfaces for the purpose of selective-area growth. 9,10) We found that the initial growth processes on these two surfaces are distinctly different when Si growth is carried out in a thermal chemical vapor deposition (CVD) mode. In particular, it was observed that the shape of the Si nuclei on SiO 2 is ball-like while those on SiN x wet on the surface.…”

Selective Area Growth of Si on Thin Insulating Layers for Nanostructure Fabrication

“…8) In this letter, we report the successful application of such a SiO 2 /SiN x bilayer mask structure to selective-area growth of Si. Figure 1(b) shows a schematic cross section of a Si nanostructure fabricated on the SiO 2 /SiN x bilayer mask.…”