Recovery of Forming Gas Damaged Pb(Nb,Zr,Ti)O3 Capacitors

Published

October 12, 2021

Author(s)

S Aggarwal, S R. Perusse, C J. Kerr, R Ramesh, D B. Romero, J T. Evans, L Boyer, J Velasquez

Abstract

We report on the recovery of fully integrated Pb(Nb,Zr,Ti)O₃ ferroelectric capacitors damaged during forming gas (4% H₂, balance N₂) annealing. In such capacitors oxygen loss, lead loss and hydrogen incorporation are three degradation mechanisms that have been identified. The capacitors were encapsulated using TiO_x and SiO₂ as inter-level dielectrics to prevent any loss of oxygen or lead. Hydrogen however diffused into the ferroelectric film leading to the loss of ferroelectricity. To recover the properties of the capacitor, the fully integrated structure was annealed in VLSI grade N₂ ambient to drive the hydrogen out. Raman scattering experiments performed in the high frequency regime to detect the [OH-] stretching vibration mode confirmed the removal of hydrogen after annealing in VLSI grade N₂. The ferroelectric properties including polarization and resistivity of the capacitors was restored to their original values prior to damage. This shows that the process of hydrogen damage is reversible with time to recovery being dependent on the amount of hydrogen in the forming gas.

Citation

Applied Physics Letters

Pub Type

Journals

Keywords

ferroelectric, hydrogen incorporation, Pb(Ni, Zr, Ti)O₃

Citation

Aggarwal, S. , Perusse, S. , Kerr, C. , Ramesh, R. , Romero, D. , Evans, J. , Boyer, L. and Velasquez, J. (2021), Recovery of Forming Gas Damaged Pb(Nb,Zr,Ti)O₃ Capacitors, Applied Physics Letters (Accessed July 27, 2024)