Interplay of Precursor and Plasma for The Deposition of HfO2 via PEALD: Film Growth and Dielectric Properties

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Florian Preischel - , Ruhr University Bochum (Author)
  • David Zanders - , Ruhr University Bochum (Author)
  • Thomas Berning - , Ruhr University Bochum (Author)
  • Aleksander Kostka - , Ruhr University Bochum (Author)
  • Detlef Rogalla - , Ruhr University Bochum (Author)
  • Claudia Bock - , Ruhr University Bochum (Author)
  • Anjana Devi - , Ruhr University Bochum, Fraunhofer Institute for Microelectronic Circuits and Systems (Author)

Abstract

HfO2 thin films are appealing for microelectronic applications such as high-κ dielectric layers, memristors, and ferroelectric memory devices. To fulfill the different requirements of each application, the properties of the deposited material need to be tuned accordingly. In this context, plasma-enhanced atomic layer deposition (PEALD) is a powerful processing route to tailor the properties of HfO2 thin films, especially at low temperatures. Herein, a comprehensive bottom-up approach is presented, ranging from the synthesis of molecularly engineered Hf precursors to the development of a HfO2 PEALD process and a detailed evaluation where plasma can be exploited to tune the dielectric properties. With the example of the newly synthesized bis-(dialkylamido)-bis-(formamidinato) Hf(IV) precursor, [Hf{η2-(iPrN)2CH}2(NMe2)2] which is reactive, thermally robust and volatile, successful implementation in a PEALD process for HfO2 at low temperatures is demonstrated. The typical atomic layer deposition (ALD) characteristics of precursor saturation, linearity, and ALD temperature window are demonstrated with constant growth of 0.7 Å per cycle from 125 to 200 °C, yielding high-purity layers. The effect of plasma pulse duration on the chemical composition alongside structural, topographical, as well as dielectric properties of the films is investigated. For the latter, the films are incorporated in metal-insulator semiconductor (MIS) structures.

Details

Original languageEnglish
Article number2300244
JournalAdvanced materials interfaces
Volume10
Issue number28
Publication statusPublished - 4 Oct 2023
Peer-reviewedYes
Externally publishedYes

Keywords

Keywords

  • dielectric properties, hafnium(IV) oxide, plasma-enhanced atomic layer deposition, precursors, thin films