| AVS 65th International Symposium & Exhibition | |
| Plasma Science and Technology Division | Monday Sessions |
| Session PS+TF-MoM |
| Session: | Plasma Deposition and Plasma-Enhanced ALD |
| Presenter: | Tahsin Faraz, Eindhoven University of Technology, The Netherlands |
| Authors: | T.F. Faraz, Eindhoven University of Technology, The Netherlands K. Arts, Eindhoven University of Technology, The Netherlands S. Karwal, Eindhoven University of Technology, The Netherlands M.C. Creatore, Eindhoven University of Technology, The Netherlands H.C.M. Knoops, Oxford Instruments, The Netherlands W.M.M. Kessels, Eindhoven University of Technology, The Netherlands |
| Correspondent: | Click to Email |
As we enter an era of atomic scale device dimensions, there is a significant demand for synthesizing ultrathin films with precise growth control. Plasma-enhanced atomic layer deposition (PEALD) has obtained a prominent position in obtaining films with atomic scale precision. Although the effects of ion-surface interactions have been investigated for conventional plasma-enhanced chemical and physical vapor deposition in great detail, very little is known about the role of ions during PEALD. In this work, we demonstrate how the properties of materials (oxides and nitrides of Ti, Hf and Si) grown using PEALD (on planar and 3D substrates) can be tailored by controlling the kinetic energy of ions, Ei, impinging on a growing film surface with RF substrate biasing.1 This technique harnesses the well-known synergism of ion-radical processes under energetic ion bombardment during reactive plasma exposure. It was demonstrated to significantly enhance the versatility of PEALD processes by providing two knobs (magnitude and duration of bias) enabling control over materials with dielectric or conductive properties, relevant for a wide variety of applications.
We measured Ei characteristics of reactive plasmas typically used for PEALD (O2, H2, N2) to investigate their role in tailoring material properties. Performing such measurements is essential towards understanding how a given PEALD process at different operating conditions can be influenced by energetic ions. Ion energy distributions (IEDs) were measured in a commercial 200-mm remote inductively-coupled-plasma (ICP) ALD system equipped with RF substrate biasing. IEDs were obtained using a gridded retarding field energy analyzer (RFEA) for the aforementioned plasmas without and with RF biasing. The properties of materials grown using these plasmas in this ALD system were analyzed as a function of the parameters derived from IEDs. These results have provided more insight on the relation between ion characteristics and the ensuing properties, e.g., identifying Ei thresholds between property improvement and degradation. They demonstrate how the measurement and control of Ei characteristics during PEALD provides a platform for synthesizing ultrathin films with desired properties.
Furthermore, we analyzed the effects of controlling Ei during PEALD on 3D substrates frequently employed in state-of-the-art devices. It yielded an intriguing effect of inducing differing material properties at different surfaces of 3D trench nanostructures. This demonstrated the potential of this technique in enabling new routes for achieving topographically selective deposition.
1Faraz et al. ACS Appl. Mater. Interfaces 10, 13158 (2018)