Nanolithography with metastable neon atoms: Enhanced rate of contamination resist formation for nanostructure fabrication

Abstract

We report a sevenfold improvement in the rate of contamination resist formation over previous experiments by using metastable neon atoms for nanolithography. Chemically assisted ion beam etching was used to transfer the resist pattern into the substrate. We demonstrate the fabrication of 50-nm-wide features in GaAs with well-defined edges and an aspect ratio >2:1. These are the best resolution and highest aspect ratio features that have been achieved with metastable atom lithography. The resist formation rate by the metastable neon atoms and the etch selectivity of the contamination resist with GaAs were measured.

Electron Cyclotron Resonance Based Chemically Assisted Plasma Etching Of Silicon in CF4/Ar Plasma

“…The development of Reactive Ion Etching (RIE) & Chemically Assisted Ion Beam Etching (CAIBE) has contributed a great deal to the fabrication of much smaller semiconductor devices [1] MEMS [2], Nano cavities and nano-structure [3]. The processing in these modes has achieved very good maturity for etching of silicon and silicon related materials but however some improvement in etching is always been carried out mainly by trial and error on the work front.…”

Atom Lithography: Fabricating Arrays of Silicon Microstructures Using Self-Assembled Monolayer Resist and Metastable Helium Beam

“…At high doses, further degradation of the hydrocarbon molecules caused fragmentation of the carbon chain, and cross-linking polymerization between adjacent fragmented SAM molecules might occur, giving rise to the formation of a highly resistant carbonaceous layer and leading to a negative pattern [36]. In addition, the contamination resist, which was induced by hydrocarbon molecules remaining on the inner wall of the vacuum chambers, remained a concern [40][41]. When the metastable atoms impacted the surface, they transferred their internal energy to these physisorbed hydrocarbon molecules and induced a polymerization change within the exposed region.…”

“…were optimized further, higher resolution of the patterning onto the silicon substrates could be obtained. Athough the interaction between the outermost surface of the SAM and the irradiation of metstable atoms has been investigated for about ten years [34][35][36][37][38][39][40][41], the detailed change in surface chemistry of the outermost of the SAM molecules under the irradiation of helium atom beam is still difficult to predict and remains to be explored. What we demonstrated in the present study was that both the positive-tone and the negative-tone sensitivity of the SAM were related to largely different dosage of MAB and the length of the alkyl chains of SAM molecule (as illustrated in scheme 1 (IV) and (V)).…”

Negative resist behavior of neutral sodium atoms deposited on self-assembled monolayers

“…or in transport prior to exposure. Because contamination lithography in NAL is usually performed in diffusion pumped systems, 11,12 with longer exposure times and energetically different species ͑metastable noble gas atoms͒, we believe this to be at most a minor effect.…”

“…6-8͔͒ and metastable noble gas atoms ͑He, Ne, and Ar͒. [9][10][11][12][13] Most of these atoms have been shown to modify various types of molecular monolayers or self-assembled monolayers ͑SAMs͒ on several substrates including Au and SiO 2 . The mechanism through which the etch resistivity is modified can be very different for various atomic species, internal energy, kinetic energy, or resist.…”