Conformality of remote plasma-enhanced atomic layer deposition processes: An experimental study

Abstract

In total, five metal oxide and one metal plasma-enhanced atomic layer deposition (PEALD) processes were studied with respect to the conformality of the coatings. The study reveals that also high aspect ratio structures (up to 60:1) can be coated conformally with remote PEALD. Oxides could relatively easily be deposited into demanding 3D structures with rather short cycle times but not the silver metal. The key factor in achieving excellent conformality seems to be that sufficient radical density is required to overcome the loss of radicals by recombination. In the case of metals where hydrogen plasma is applied the recombination of hydrogen radicals causes major difficulties in obtaining perfect conformality.

Microscopic silicon-based lateral high-aspect-ratio structures for thin film conformality analysis

“…3) or more demanding AR of about 40:1. 11,12 With macroscopic lateral high-aspect-ratio (LHAR) test structures, 13,14 accurate thickness profiles along the gap have been recorded with AR up to 200:1. Because of the macroscopic dimensions (gap size on the order of 100 lm), molecular flow inside these LHAR structures is reached only in high vacuum (e.g., 10 À4 Torr).…”

Antireflection Coatings for Strongly Curved Glass Lenses by Atomic Layer Deposition

“…Due to this cyclic surface-controlled growth, ALD inherently offers precise thickness control, good thickness uniformity and high reproducibility. It is well known for its conformal film growth on complex nanostructures with high aspect ratios [23,24]. In this work, the capability of ALD for deposition of antireflection coatings on highly curved lenses has been analyzed.…”

Enhanced deep ultraviolet inverse polarization transmission through hybrid Al-SiO2 gratings

“…6, we propose to increase g TE by conformally filling the grating slits with dielectric material by Atomic Layer Deposition (ALD). [14][15][16] With proper grating design, we minimize the reflection of the lowest-order TE guided mode at the exit interface. Experimentally, we observe a 35 dB extinction ratio at k ¼ 196 nm, which is far above previously reported values.…”