Selective Atomic Layer Deposition (SALD) of Titanium Dioxide on Silicon and Copper Patterned Substrates

Abstract

Atomic Layer Deposition (ALD) of TiO 2  has potential applications in the microelectronics industry for purposes such as formation of the copper barrier layer. In this paper, TiO 2  deposition on silicon and copper substrates is studied, with a focus on the initial growth and nucleation period on different substrates. Silicon with native oxide about 1.5 nm-thick, silicon with reduced oxide <1 nm-thick, and silicon/copper patterned substrates with native oxide are tested for TiO 2  deposition. The temperature-independent window on silicon is studied, and findings are used encourage selective deposition on the silicon portions of a copper-patterned silicon substrate. Selective ALD is found to be possible on silicon portions by taking advantage of the 15-20 cycle TiO 2  nucleation period on copper, allowing a film approximately 2.5 nm-thick to grow on silicon while less than two monolayers grow on copper. Findings can be used in future work to further promote selective deposition of TiO 2 .