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The influence of megasonic agitation on the development of nanostructures with high aspect ratio is investigated thoroughly. The improvements in homogeneity, depth, and quality of nanostructures are related to specific interactions of the sound wave with the resist and developer. Two phases in the development process are operative. The specific role of microstreaming providing physical supply of fresh developer is identified and the reduction of viscosity by megasonic interaction is derived. The advantage of megasonic agitation as a nondestructive development of high aspect ratio nanostructures is demonstrated.

A high-gain photodetector based on junctionless MOSEFT has been presented in this work. Tri-gate junctionless nanowire phototransistors were fabricated on (100) silicon-on-insulator wafers with a buried oxide of thickness 145 nm and top silicon layer of thickness 10 nm. The gate stack consisted of a 10 nm SiO2 dielectric and a 50 nm poly-Si gate electrode. The channel length and doping concentration of junctionless n-MOSFETs was 1 μm and 3 × 1019 cm−3, respectively. The dark current of this device measured at room temperature was less than 1 pA. The measured internal gain of the device was about 35 for 860 nm light illumination. The photocurrent was 300 times larger than the dark current for only 30 nW incident power on the nanowire at 300 mV drain bias.