Nh4oh Wet Etching For Silicon Nano Or Sub-Micron Wires

In this work, instead of TMAH (Tetra Methyl Ammonium Hydroxide), ammonium hydroxide (NH4OH) solutions are used to get silicon nano (SiNWs) or sub-micron (SiSMWs) wires, because also these solutions are silicon orientation-dependent wet etching and fully compatible with CMOS (Complementary Metal - Oxide - Semiconductor) technology.These wires were fabricated on Si and SOI (SiliconOn-Insulator) wafers, with (100) crystallographic orientation surfaces. On both wafers, the lateral etch rates under SiO2 of < 110 > plane Si wire sidewalls between 43 nm/min and 156 nm/min were obtained. Thus,SiNWs and SiSMWs were obtained, indicating that our NH4OH solution is a new alternative to get 3D structures on Si and SOI substrates. To confirm this result, pseudo-MOS (Metal-Oxide-Silicon) transistor on SOI substrate, with conduction channel of n+ Si wire of width of 1.22 gm and height of 100 nm, was fabricated. From drain-source current (I-DS) versus back gate - source voltage (V-BGS) curve of Pseudo MOS transistor, the threshold voltage (V-T) of 1.36 V and the maximum transconductance of 20 mu S were extracted.