Chemical route to ferroelectric thin film capacitors

For the first time the fabrication of ferroelectric SrBi2(Ta,Nb)(2)O-9 thin film capacitors with RuO2 electrodes is conducted using a full chemical route. SrBi2(Ta,Nb)(2)O-9 sols were obtained from niobium and tantalum ethoxides mixed with bismuth and strontium 2-ethylhexanoates. RuO2 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/RuO2/ SrBi2(Ta,Nb)(2)O-9/RuO2 sequence. Fully crystallized crack-free materials (RuO2 and SrBi2(Ta,Nb)(2)O-9) were obtained bq, annealing at 700 degrees C for 2 h. Hysteresis loops (3-10 V) are similar to those observed using platinum electrodes. (C) 1999 Elsevier Science Limited. All rights reserved.