Recovery of Forming Gas Damaged Pb(Nb,Zr,Ti)O3 Capacitors
S Aggarwal, S R. Perusse, C J. Kerr, R Ramesh, D B. Romero, J T. Evans, L Boyer, J Velasquez
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 TiOx 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.
, Perusse, S.
, Kerr, C.
, Ramesh, R.
, Romero, D.
, Evans, J.
, Boyer, L.
and Velasquez, J.
Recovery of Forming Gas Damaged Pb(Nb,Zr,Ti)O<sub>3</sub> Capacitors, Applied Physics Letters
(Accessed December 10, 2023)