Deposition behavior of Si on insulating and conducting substrates in the CVD process: approach by charged cluster model

Abstract

Deposition behaviors of silicon on dielectric and conducting substrates were studied focussing on the deposition mechanism in the Si-CI-H system. On the dielectric substrate, silicon particles were deposited after some incubation time and then etched away at a later stage under the same processing conditions. On the conducting substrate, silicon particles were deposited without an incubation time with no observed etching during the experimental time period. In the early stages of etching on the dielectric substrate, the number of silicon particles decreased but the remaining unetched particles became larger, indicating that growth and etching took place simultaneously. This paradoxical phenomenon can be explained on a sound thermodynamic basis if we assume that charged clusters are formed in the gas phase and these clusters are the growth unit. The selective deposition on the conducting material as opposed to the dielectric material can also be explained by the electrostatic interaction between the charged cluster and the conducting or dielectric material. (C) 1999 Elsevier Science B.V. All rights reserved.