Estimation of pattern resolution using NaCl high-contrast developer by Monte Carlo simulation of electron beam lithography

Zhang, Hui; Huda, Miftakhul; Komori, Takuya; Yin, You; Hosaka, Sumio

doi:10.1016/j.mee.2014.04.039

Cited by 2 publications

(2 citation statements)

References 27 publications

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“…To fabricate NWs with different widths, the structure of the NWs was designed in various width scales (from 4 to 10 nm) using a computer design software (VectorWorks). The fabricated widths of HSQ NWs depend on the design width and are determined by the beam spot size, beam focusing techniques, and exposure dosages. , Therefore, design widths and exposure dosages using good beam focusing techniques were controlled to form NWs with different widths. To transfer HSQ NW patterns into the top Si layer of the SOI wafer, ICP-RIE was performed via CF 4 plasma etching.…”

Section: Methodsmentioning

confidence: 99%

Estimation of the Depletion Layer Thickness in Silicon Nanowire-Based Biosensors from Attomolar-Level Biomolecular Detection

Zhang

Qiu

Osawa

et al. 2023

ACS Appl. Mater. Interfaces

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Silicon nanowire (SiNW) biosensors have attracted a lot of attention due to their superior sensitivity. Recently, the dependence of biomolecule detection sensitivity on the nanowire (NW) width, number, and doping density has been partially investigated. However, the primary reason for achieving ultrahigh sensitivity has not been elucidated thus far. In this study, we designed and fabricated SiNW biosensors with different widths (10.8–155 nm) by integrating a complementary metal-oxide-semiconductor process and electron beam lithography. We aimed to investigate the detection limit of SiNW biosensors and reveal the critical effect of the 10-nm-scaled SiNW width on the detection sensitivity. The sensing performance was evaluated by detecting antiovalbumin immunoglobulin G (IgG) with various concentrations (from 6 aM to 600 nM). The initial thickness of the depletion region of the SiNW and the changes in the depletion region due to biomolecule binding were calculated. The basis of this calculation are the resistance change ratios as functions of IgG concentrations using SiNWs with different widths. The calculation results reveal that the proportion of the depletion region over the entire SiNW channel is the essential reason for high-sensitivity detection. Therefore, this study is crucial for an indepth understanding on how to maximize the sensitivity of SiNW biosensors.

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Section: Methodsmentioning

confidence: 99%

Estimation of the Depletion Layer Thickness in Silicon Nanowire-Based Biosensors from Attomolar-Level Biomolecular Detection

Zhang

Qiu

Osawa

et al. 2023

ACS Appl. Mater. Interfaces

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“…The EB writing system is a combination of a high-resolution scanning electron microscope (SEM) with a Schottky emission-type field-emission electron gun (JSM6500F, JEOL) and a drawing controller (Beam Draw, Tokyo Technology) . To form narrow nanowires with high-resolution, negative-tone resist hydrogen silsesquioxane (HSQ, Dow Corning) and a high-contrast salty development solution , were employed. Normally, a thin HSQ resist layer would be employed to form a high-resolution pattern because the EB scattering range (lateral) in a thin resist layer is smaller than that in a thick resist layer.…”

Section: Methodsmentioning

confidence: 99%

Design and Fabrication of Silicon Nanowire-Based Biosensors with Integration of Critical Factors: Toward Ultrasensitive Specific Detection of Biomolecules

Zhang

Kikuchi

Ohshima

et al. 2020

ACS Appl. Mater. Interfaces

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As critical factors affecting the sensing performance of silicon nanowire (SiNW) biosensors, the structure, functional interface, and detection target were analyzed and designed to improve sensing performance. For an improved understanding of the dependence of sensor structure on sensitivity, a simple theoretical analysis was proposed to predict the sensitivity of biosensors with different SiNW types, widths, and doping concentrations. Based on the theoretical analysis, a biosensor integrating optimized critical factors was designed and fabricated. Optimizations focusing on the following aspects are considered: (1) employing n-type SiNW and controlling the impurity doping concentration of SiNW at approximately 2 × 1016–6 × 1016 atoms/cm3 to obtain a suitable charge density, (2) minimizing the SiNW width to 16.0 nm to increase the surface area-to-volume ratio, (3) using a native oxide layer on SiNW as a gate insulator to transport the captured charge molecules closer to the SiNW surface, (4) modifying the SiNW surface by 2-aminoethylphosphonic acid coupling to form a high-density self-assembled monolayer for enhancing the stability bound molecules, and (5) functionalizing the SiNW with ovalbumin molecules for specifically capturing the target immunoglobulin G (IgG) molecules. The sensing performance was evaluated by detecting IgG with concentrations ranging from 6 aM to 600 nM and control experiments. The SiNW biosensor revealed ultrahigh sensitivity and specific detection of target IgG with a measured limit of detection of 6 aM. The integration of the critical SiNW biosensor factors provides a significant possibility of a rapid and ultrasensitive diagnosis of diseases at their early stages.

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Estimation of pattern resolution using NaCl high-contrast developer by Monte Carlo simulation of electron beam lithography

Cited by 2 publications

References 27 publications

Estimation of the Depletion Layer Thickness in Silicon Nanowire-Based Biosensors from Attomolar-Level Biomolecular Detection

Estimation of the Depletion Layer Thickness in Silicon Nanowire-Based Biosensors from Attomolar-Level Biomolecular Detection

Design and Fabrication of Silicon Nanowire-Based Biosensors with Integration of Critical Factors: Toward Ultrasensitive Specific Detection of Biomolecules

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