Tuning Material Properties of Oxides and Nitrides by Substrate Biasing during Plasma-Enhanced Atomic Layer Deposition on Planar and 3D Substrate Topographies

Abstract

Oxide and nitride thin-films of Ti, Hf, and Si serve numerous applications owing to the diverse range of their material properties. It is therefore imperative to have proper control over these properties during materials processing. Ion-surface interactions during plasma processing techniques can influence the properties of a growing film. In this work, we investigated the effects of controlling ion characteristics (energy, dose) on the properties of the aforementioned materials during plasma-enhanced atomic layer deposition (PEALD) on planar and 3D substrate topographies. We used a 200 mm remote PEALD system equipped with substrate biasing to control the energy and dose of ions by varying the magnitude and duration of the applied bias, respectively, during plasma exposure. Implementing substrate biasing in these forms enhanced PEALD process capability by providing two additional parameters for tuning a wide range of material properties. Below the regimes of ion-induced degradation, enhancing ion energies with substrate biasing during PEALD increased the refractive index and mass density of TiOx and HfOx and enabled control over their crystalline properties. PEALD of these oxides with substrate biasing at 150 °C led to the formation of crystalline material at the low temperature, which would otherwise yield amorphous films for deposition without biasing. Enhanced ion energies drastically reduced the resistivity of conductive TiNx and HfNx films. Furthermore, biasing during PEALD enabled the residual stress of these materials to be altered from tensile to compressive. The properties of SiOx were slightly improved whereas those of SiNx were degraded as a function of substrate biasing. PEALD on 3D trench nanostructures with biasing induced differing film properties at different regions of the 3D substrate. On the basis of the results presented herein, prospects afforded by the implementation of this technique during PEALD, such as enabling new routes for topographically selective deposition on 3D substrates, are discussed.

Plasma-Assisted ALD of Highly Conductive HfNx: On the Effect of Energetic Ions on Film Microstructure

“…So to conclude, the obtained results demonstrate how energy density and mass of impinging ions and the associated energy and momentum transfer during plasma ALD can contribute to the fine tuning of the chemical and microstructural properties of HfN x thin films. The results may be applicable to wide range of ALD processes including for the growth of other transition metal nitrides [54].…”

Antireflection Coating on PMMA Substrates by Atomic Layer Deposition

“…The thin films were deposited using a commercial Oxford Instruments Plasma Technology (Bristol, UK) open load ALD reactor (OpAL™) equipped with an inductively coupled plasma (ICP) RF generator, operating at 13.56 MHz. Schematics of a similar experimental setup was presented by Faraz et al [21]. Processes were developed to achieve a reproducible growth rate and optical properties along with a non-uniformity, NU < 5% on 200 mm area.…”

MOS Capacitance Measurements for PEALD TiO2 Dielectric Films Grown under Different Conditions and the Impact of Al2O3 Partial-Monolayer Insertion

“…The properties and applicability of TiO 2 thin films are intrinsically related to their crystal structure. In this sense, they have been mainly produced in amorphous, anatase and/or rutile structure forms by a wide range of techniques, namely sol-gel [21,22], magnetron sputtering [23,24], chemical vapor deposition (CVD) [25], physical vapor deposition (PVD) [26], atomic layer deposition (ALD) [27,28] and plasma-enhanced atomic layer deposition (PEALD) [29][30][31][32][33][34]. Among them, PEALD requires lower substrate and process temperatures to obtain crystalline films [35].…”

“…Among them, PEALD requires lower substrate and process temperatures to obtain crystalline films [35]. It is also one of the most promising technologies for the growth of conformal coatings and nanolaminates in various structures and topographies [32,36] with layer thickness precisely defined by self-limited surface reactions [37]. During the PEALD of metal oxide films, oxygen (O 2 ) plasma is used as an oxidant source [38].…”