Surface reaction mechanisms during the atomic layer deposition of silicon-based dielectrics

The continuous shrinking of semiconductor devices beyond the current 14 nm technology node has kindled a need for the low-temperature (≤400 °C) highly-conformal (>95%) atomic layer deposition (ALD) of Si-based dielectric films for applications such as sidewall spacers in multiple patterning. In this work, we have primarily focused on understanding the surface reaction mechanisms during the ALD of Si-based dielectric films using in situ attenuated total reflection Fourier transform infrared spectroscopy. Initially, we looked at a baseline SiNx ALD process using alternating exposures of Si2Cl6 and NH3 plasma. Our infrared spectra show that H was incorporated during both half cycles in the form of –NH species, leading to a high H content and poor film quality. To improve the film quality, two approaches were considered: C incorporation and H content reduction. For the first approach, we developed and tested a framework for the incorporation of C during SiNx and SiO2 ALD to deposit SiCxNy and SiCxOy films. The framework was used to develop a novel SiCxNy ALD process using Si2Cl6 and CH3NH2 plasma. This process incorporated up to ~10% C in the form of Si–N=C=N–Si species, but H was once again incorporated during both half-cycles leading to a similar H content and film quality as the baseline SiNx ALD process. For the second approach, the H content of the films was lowered by replacing the N- and H-containing plasma with a N2 plasma. This was enabled by a novel three-step SiNx ALD process using Si2Cl6, CH3NH2, and N2 plasma. The three-step process lowered the H content by a factor of ~2, and the SiNx films were more conformal than films deposited using other N2-plasma-based SiNx ALD processes. Additionally, to probe the chemical differences between the planar and sidewall of Si based dielectric films deposited on high-aspect-ratio nanostructures using ALD, we designed and tested a novel transmission FTIR spectroscopy setup.

Name thesis:degree_name

Doctor of Philosophy (Ph.D.)

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Chemical and Biological Engineering

Grantor dc:publisher

Colorado School of Mines. Arthur Lakes Library

Year dc:date.issued

2018

Author dc:creator

• Ovanesyan, Rafaiel A.

Advisor dc:contributor.advisor

• Agarwal, Sumit

Committee members dc:contributor.committeemember

• Wolden, Colin Andrew
• Pylypenko, Svitlana
• Gomez-Gualdron, Diego A.
• Hausmann, Dennis

• dielectrics
• silicon
• atomic layer deposition
• surface science
• infrared spectroscopy

Statement dc:rights

• Copyright of the original work is retained by the author.

Language dc:language.iso

eng, English

Identifier

T 8473

OAI identifier oai:identifier

oai:repository.mines.edu:11124/172268