Area selective deposition of silicon by plasma enhanced chemical vapor deposition using a fluorinated precursor

Ghewa Akiki,Daniel Suchet,Dmitri Daineka,Sergej Filonovich,Pavel Bulkin,Erik V Johnson

doi:10.1016/j.apsusc.2020.147305

Abstract

An Area Selective Deposition (ASD) process using Plasma-Enhanced Chemical Vapour Deposition (PECVD) is demonstrated. Using a plasma chemistry containing a fluorinated silicon precursor (SiF4), no deposition is observed on an aluminum oxide (AlOX) surface area, whereas a thin film of silicon is deposited on a silicon nitride (SiNX) surface area, while both areas are located on the same crystalline silicon substrate. The thin film deposition is characterized using spectroscopic ellipsometry, scanning electron microscopy, and atomic force microscopy, showing that 10 nm of silicon is deposited on the SiNx in 4 min. The growth on the SiNX is characterized by small grains and a rough surface, consistent with microcrystalline silicon, while no deposition or etching is observed for the AlOX surface.

Highlights

Area selective deposition (ASD) is an attractive process for applications such as microelectronics as it may eliminate some costly lithography steps and reduce the issue of edge placement errors [1]
We report on the observation of a significant surfacedependent nucleation delay in the Plasma-Enhanced Chemical Vapour Deposition (PECVD) of hydrogenated microcrystalline silicon films using a standard 13.56 MHz radio frequency excitation source and a fluorinated silicon growth precursor
The spectroscopy ellipsometry (SE) results show that the silicon layer that has grown on the SiNX area can be optically modelled as a continuous thin film, and that optically, no difference can be detected in the aluminum oxide (AlOX) region before and after the process

Summary

Introduction

Area selective deposition (ASD) is an attractive process for applications such as microelectronics as it may eliminate some costly lithography steps and reduce the issue of edge placement errors [1]. This bottom-up approach controls where deposition takes place through the underlying surface rather than through any masking step, and results in “growth” and “no-growth” areas depending on the nature of surface material. Recent research in this field predominantly employs two techniques: atomic layer deposition (ALD) and self-assembling monolayers (SAMs). We report on the observation of a significant surfacedependent nucleation delay in the PECVD of hydrogenated microcrystalline silicon (μc-Si:H) films using a standard 13.56 MHz radio frequency excitation source and a fluorinated silicon growth precursor

Experimental details

Results and discussion

Conclusions