Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

Development of an etching process for fabrication of ultrathin silicon nanowires (SiNWs) with inductively coupled plasma (ICP) source and C4F8/SF6 mixed gas recipe at 18 oC is reported. Etch selectivity of silicon (SOI) to hydrogen silsesquioxane (HSQ), a negative tone electron beam resist and selectivity of silicon (SOI) to SiO2 are investigated to identify suitable process window. Effects of ICP power, RF power, chamber pressure, flow rates and ratio of C4F8/SF6 on etch rate, selectivity and surface roughness are examined. Atomic force microscopy (AFM) is used for identifying surface roughness of the plain silicon (SOI) substrates after etching. Thereafter etching of HSQ patterned substrates is performed. Scanning electron microscopy is performed to observe the etch profile. Parameters such as flow rates of C4F8/SF6 are optimized to attain sub-50 nm SiNWs with smooth and vertical sidewalls.