Chemical route to ferroelectric thin film capacitors

Abstract For the first time the fabrication of ferroelectric SrBi 2 (Ta,Nb) 2 O 9 thin film capacitors with RuO 2 electrodes is conducted using a full chemical route. SrBi 2 (Ta,Nb) 2 O 9 sols were obtained from niobium and tantalum ethoxides mixed with bismuth and strontium 2-ethylhexanoates. RuO 2 sols were prepared by dissolving an aqueous solution of ruthenium nitrosylnitrate into 2-methoxyethanol. Capacitors were fabricated by spin coating the precursor solutions on silicon wafers according to the Si/RuO 2 /SrBi 2 (Ta,Nb) 2 O 9 /RuO 2 sequence. Fully crystallized crack-free materials (RuO 2 and SrBi 2 (Ta,Nb) 2 O 9 ) were obtained by annealing at 700°C for 2 h. Hysteresis loops (3–10 V) are similar to those observed using platinum electrodes.