Self-Assembled Monolayer Electron-Beam Resists on Gaas and SiO2

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M. J. Lercel, R. C. Tiberio, P. F. Chapman, H. G. Craighead, C. W. Sheen, A. N. Parikh, D. L. Allara, Journal of Vacuum Science & Technology B 11, 2823 (1993)

It was demonstrated that self‐assembled monolayers of n‐octadecanethiol [ODT; CH3(CH2)17SH] on GaAs and n‐octadecyltrichlorosilane [OTS; CH3(CH2)17SiCl3] on SiO2 act as self‐developing positive electron beam resists with electron‐beam sensitivities of ∼100–200 μC/cm2. For the OTS monolayer on a silicon native oxide, atomic force microscopy (AFM) images of the exposed layer before etching demonstrate the removal of all or part of the layer upon electron‐beam exposure. Features as small as 25 nm were resolvable in a 50 nm period grating. A resist contrast curve for OTS was obtained from AFM depth measurements as a function of dose. An ammonium hydroxide water etch was used to transfer patterns into the GaAs to a depth of at least 30 nm and buffered HF was used for pattern transfer into the SiO2 to a depth of at least 50 nm.

DOI: 10.1116/1.586609

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