Fabrication of silicon nanodots on insulator using block copolymer thin film

Abstract

Dense and periodically distributed silicon nanodots were fabricated on silicon dioxide layer using block copolymer. Self-assembling resists were coated on the polysilicon/oxide/silicon substrate to produce a layer of uniformly distributed parallel nano-cylinders of polymethyl methacrylate (PMMA) in a polystyrene (PS) matrix. The PMMA cylinders were degraded and removed by acetic acid rinsing, forming a PS template to transfer the pattern. The patterned cylindrical vacant cavities of the PS template were approximately 22 nm in diameter, 40 nm deep, and 50 nm apart. 5-nm- and 6-nm-thick Ni thin films were deposited by using an e-beam evaporator. The PS template was removed by a lift-off process using N-formyldimethylamine (DMF). Arrays of Ni nanodots were dry-etched using fluorine-based reactive ion etching (RIE), forming silicon nanodots. The sizes of the silicon nanodots were in the range of 10 nm to 30 nm, depending on the etching time. (C) 2009 Published by Elsevier B.V.