Area-Selective ALD of TiO₂ Nanolines with Electron-Beam Lithography

Abstract

We demonstrate a bottom-up approach to fabricate nanoline structures using self-assembled monolayer (SAM) modified substrates to selectively prevent nucleation during atomic layer deposition (ALD). Low-energy (≤5 kV) electron-beam lithography (EBL) was used to modify the hydrophobic functional groups (−CH 3 ) of octadecyltrichlorosilane (OTS) SAM to hydrophilic species (e.g., −COOH), which allows chemisorption of the titanium isopropoxide (TTIP) and water to initiate titanium oxide (TiO 2 ) nucleation. TiO 2 thin films were selectively deposited on the OTS molecules which were properly functionalized or patterned. We systematically investigate the effects of e-beam dose and accelerating voltage on selective TiO 2 deposition with nanoline patterns. The results indicate that the former parameter determines the resolution of individual line width, while the latter one is attributed to the minimum pitch dimension of dense line patterns achievable. Using the optimal e-beam parameters, i.e., accelerating voltages of 1−2 kV and a line dose of 10 nC/cm, TiO 2 nanolines with a maximum resolution of 30 nm and a minimum pitch of 50 nm were achieved. This study offers a new approach to fabricate closepacked nanopatterns for IC devices without any challenging etching processes.

Nanoscale selective area atomic layer deposition of TiO2using e-beam patterned polymers

“…have been exploited as mono-layered surface modiers to block ALD nucleation of various metal oxide thin lms and metallic nanoparticles/thin lms. 10,13,36,37,[41][42][43][44][45][46][47][48] In this strategy, chlorosilane compounds chemically react with hydroxyl sites on the substrate surface and expose only unreactive alkyl groups on the surface which serve as effective ALD nucleation preventing agents. Although promising, this approach depends critically on the availability of defect-free SAM blocking layers, otherwise the defects in SAM act as nucleation centers leading to reduced selectivity and eventually non-selective growth.…”

Electron-Beam Patterning of Vapor-Deposited Solid Anisole

“…[1][2][3][4][5][6][7][8][9][10][11][12] The most striking example is electron-beam lithography (EBL), which has been widely implemented for patterning micro/nano-structures with advantages of high resolution and reliability. [13][14][15][16][17][18][19][20] In EBL, an electron-sensitive resist is spin-or spray-coated on a flat substrate, then exposed by a focused e-beam and developed in a solvent for the creation of nanoscale patterns. These patterns subsequently act as stencils, which will be filled with required materials by deposition or transferred into the underlying material by etching.…”

A high-precision, template-assisted, anisotropic wet etching method for fabricating perovskite microstructure arrays

“…19 Although the direct writing method shows superiority in its exibility of design, low cost and efficient mass production, the resolution of the existing direct writing method is still relatively low. 20 As for the vapor phase method, crystal defects are few, but it generally possesses disadvantages such as high temperature, poor controllability and expensive equipment. 21 Therefore, it is In this paper, we propose a template-assisted wet etching (TAWE) method for the preparation of perovskite microstructure arrays.…”