Advances in Emerging Electronic Nanomaterials: Synthesis, Enhanced Properties, Integration, and Applications: Atomic Layer Processing: In-Situ Characterization, Modeling, Area-Selective Deposition, and Microelectronics Applications
Sponsored by: TMS: Nanomaterials Committee
Program Organizers: Chang-Yong Nam, Brookhaven National Laboratory; Jung-Kun Lee, University of Pittsburgh; Stephen McDonnell, University of Virginia
Tuesday 8:00 AM
October 11, 2022
Room: 321
Location: David L. Lawrence Convention Center
Session Chair: Chang-Yong Nam, Brookhaven National Laboratory; Christophe Vallee, SUNY Polytechnic Institute; Jiyoung Kim, University of Texas at Dallas
8:00 AM Keynote
From Atomic-scale Characterization to Atomic-scale Control of Thin Film Deposition Processes: James Engstrom1; 1Cornell University
Modern thin film deposition processes increasingly require atomic scale precision, and challenges exist both in the characterization and control of such processes. Concerning the former, over the past several years our group has been employing supersonic molecular beam techniques and in situ real time X-ray synchrotron radiation to examine a variety of systems. In this presentation we will provide examples concerning the characterization of thin film deposition processes concerning two important emerging thin film materials: organic small molecule semiconductors and transition metal dichalcogenides (TMDs). Concerning the latter challenge, we will review our recent efforts in atomic scale control of deposition processes, namely, using atomic layer deposition. We have particular interest in area-selective, composition dependent deposition. We have been pursuing a strategy where we intentionally introduce a third species, which we call the co-adsorbate, coincident with the thin film precursor to exploit competitive interactions and achieve area selective deposition.
8:40 AM Invited
Resolving the Evolution of Atomic Layer Deposited Thin Film Growth by Continuous In Situ X-ray Absorption Spectroscopy: Mingzhao Liu1; 1Brookhaven National Laboratory
In this talk, I will discuss advances in the in situ monitoring of ALD film growth over complex, 3D nano-architectures using synchrotron XANES spectroscopy. Leveraging the high photon flux of the ISS beamline at NSLS II and a dedicated, fully integrated ALD reactor, XANES data can be collected continuously during the ALD process, supplying a sequence of data probing the growth process in all stages. Specifically, the structural evolution of ALD titania is studied in situ as it accumulates under growth conditions similar to optimized lab conditions. A unified set of analysis tools are developed to interpret the time-series of spectral data and to establish growth stages based on distinguishable spectral features. MCR-ALS analysis, physically constrained, demonstrates two specific spectral components, corresponding to titania surface and bulk, with associated, time-dependent concentrations. Finally, transient spectral signatures for the intra-cycle growth kinetics are reconstructed at a time resolution of about 1s.
9:10 AM Invited
Molecular Modeling of Atomic Layer Etching: Shenli Zhang1; Yihan Huang2; Gulcin Tetiker3; Saravanapriyan Sriraman3; Roland Faller2; 1University of Chicago; 2University of California Davis; 3Lam Research
With the decrease of electronic device size down to the atomic scale, the variability of surface patterning needs to be controlled within dozens of atoms. Plasma etching is an essential surface patterning technique. Conventionally, it is realized by ionizing non-reactive species such as Ar to transfer energy to the surface, and parallel another reactive species such as Cl2 etches the surface either in its neutral or ionized state. New methods are needed to meet the requirement of precise etching control at the atomic scale, and atomic layer etching (ALE) has been proposed as one solution. We present a computational study of atomic layer etching of chlorinated germanium surfaces under argon bombardment using molecular dynamics with a newly fitted potential. The chlorination energy determines the threshold energy for etching and the number of etched atoms in the bombardment phase. We show how the etch rate is determined by bombardment energy.
9:40 AM
First-Principles Studies of Atomic Layer Deposition: Lan Li1; 1Boise State University
The nucleation mechanism for atomic layer deposition (ALD) of transition metal dichalcogenides (TMDs) has been studied using first-principles density functional theory-based methods. ALD is the self-limiting process that can deposit a range of materials at the nanoscale while maintaining chemical stoichiometry and atomic scale thickness control. It can also conform to high-aspect ratio substrate design. We found that ALD is sensitive to surface chemistry and morphology. This presentation will discuss the controlling factors for the ALD of MoS2 molybdenum disulfide – the most common TMD compound used in electronic devices. The role of surface hydroxyl group, precursor-substrate reaction, and MoS2 nucleation mechanism will be also presented.
10:00 AM Break
10:15 AM Invited
Meta-Stable Phase Ferroelectric HfZrO2 Films: Jiyoung Kim1; 1University of Texas at Dallas
Hafnia has several allotropy phases, such as monoclinic (the most thermodynamically stable phase at room temperature and 1 atm), tetragonal, cubic and orthorhombic. Recently, ferroelectric characteristics was discovered in doped hafnia thin films with meta-stable orthorhombic phase (space group: Pca21). Because of CMOS process compatibility of hafnia, doped Hf oxide thin films have been extensively investigated for ferroelectric device applications. Particularly, atomic layer deposited Hf-Zr oxide thin films shows excellent ferroelectricity and scalability at relatively low temperature (<400C). In this presentation, effects of oxidizing agents, Hf/Zr compositions and doping elements of thermal ALD will be discussed in terms of materials and electrical characteristics. Particularly, we will discuss strategies to lower the phase transition thermal budget while maintaining (or even enhancing) ferroelectric properties and reliability.
10:45 AM Invited
Microelectronics Application of Vapor-phase infiltration – Atomic Layer Deposition Derived Organic-Inorganic Hybridization Technique: Chang-Yong Nam1; 1Brookhaven National Laboratory
Vapor-phase infiltration (VPI) is an organic-inorganic hybridization technique derived from atomic layer deposition (ALD), leveraging the sorption of gaseous materials precursors in organic matrix. While performed cyclically like ALD, the reaction of materials precursors occurs within the free volume of organic matrix rather than on the surface, creating hybrids with unique materials properties. In this talk, I will showcase a few examples of VPI applications in advanced microelectronics, including enhancing the sensitivity and etch resistance of hybrid extreme ultraviolet (EUV) photoresists and reducing the stochastic resistive switching in hybrid memristors.
11:15 AM Invited
Area Selective Atomic Layer Deposition of Silicon Oxide Using an Oxygen Plasma or Ozone with Copper as the Nongrowth Surface: Sumit Agarwal1; 1Colorado School of Mines
Atomic layer deposition (ALD) offers the potential for area-selective deposition of patterned structures to enable a bottom-up fabrication of semiconductor devices. Area-selective ALD can be achieved by selectively attaching a blocking molecule to a specific surface. SiO2 ALD is unique in the sense that O3 or an O2 plasma is preferable for high throughput and a cleaner process: halogenated silane precursors such as SiCl4 along with H2O require a catalyst. The need for O radicals for deposition makes the use of organic blocking layers to inhibit growth challenging as hydrocarbons get rapidly combusted in the presence of O radicals. In this presentation, we we will demonstrate that area-selective ALD of SiO2 with O radicals while inhibiting growth on Cu with fluorinated thiols that are resistant to combustion.
11:45 AM Invited
Ions in PEALD Processes: from Material Modification to Selective Deposition: Christophe Vallee1; Marceline Bonvalot2; 1SUNY POLY; 2LTM - UGA
Most ALD processes using plasmas only use radicals from the dissociation of O2, NH3, N2 or H2 molecules. Nevertheless, there are other constituents in cold plasma that are regularly used in other processes like ions, photons, or metastable species. In this presentation we will show how by using plasma ions one can not only modify the properties of the deposited materials but also influence the growth kinetics. Controlling the ions and their energy also allows the creation of super-cycles combining ALD and ALE in the same reactor, thus opening the way to new applications such as area and topographical selective deposition.
12:15 PM Invited
Area Selective Deposition of TaN for Back End of the Line Applications: Rudy Wojtecki1; 1IBM Research | Almaden
The significant advancements in patterning and nanofabrication enable the most advanced technology nodes. However, wiring to these nanometer features requires advancements in process technologies – to ensure device performance and control takes full advantage of nanometer feature sizes where materials and processes have a direct impact on the delay in signal speed through circuit wiring, the resistive-capacitance RC-delay. We will describe the ASD of TaN, typically used as a liner material in device wiring to prevent Cu diffusion and electromigration – it is also a highly resistive metal. In this ASD method TaN was selectively deposited on dielectric surfaces without detectable levels on a metal. On patterned substrates, up to 3.8 nm of a TaN film was deposited on SiN or mesoporous SiCOH. Furthermore, modeling of this ASD process in this application suggests at advanced technology nodes resistance between metal levels may be reduced by as much as 62%.