EFFECT OF HYDROGEN ON PB(ZR, TI)O-3-BASED FERROELECTRIC CAPACITORS

The properties of ferroelectric films are known to degrade when subjec ted to hydrogen in forming gas anneals. Earlier studies have attribute d this degradation to the loss of oxygen from these films during these anneals. In this study, we show that though oxygen is lost during for ming gas annealing, hydrogen incorporation is the primary mechanism fo r the degradation of ferroelectric properties. Raman spectra obtained from the forming gas-annealed films show evidence of polar hydroxil [O H-] bonds in the films. The most probable site for hydrogen ions is di scussed based on ionic radii, crystal structure, electrical properties , and Raman spectra. We propose that the hydrogen ion is bonded with o ne of the apical oxygen ions and prevents the Ti ion from switching. P yroelectric measurements on forming gas-annealed capacitors confirm th at the capacitors no longer possess spontaneous polarization. (C) 1998 American Institute of Physics. [S0003-6951(98)03940-0].