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Ferroelectric thin films have been grown using buffer layers on
silicon as a multilayer structure by means of pulsed laser
deposition in the present experiment. Various buffer
layers were investigated for use in Pb1-xSrxTiO3 (PSrT) thin
films deposited on silicon. Deposition of La3+ or Y3+ donor
doped SrTiO3 buffer layer (SLTO or SYTO) has shown that
increase in crystalinity correlates with enhancement in the
substrate temperature. Both La3+ and Y3+ doped SrTiO3 showed
semiconductive characteristics after annealed in oxygen
atmosphere at 500℃. Pb0.99Sr0.01TiO3 films were deposited on
buffer layers and the capacitance- voltage (C-V) curves
indicated that the Pb0.99Sr0.01TiO3deposited on SLTO/Si or SYTO/
Si substrates showed ferroelectric properties. Highly (moo)
textured Pb1-xSrxTiO3 films were grown on La0.5Sr0.5CoO3 (LSCO)
buffer layers. The Pb0.99Sr0.01TiO3 film showed a relatively
larger polarization than the Pb0.8Sr0.2TiO3 and Pb0.6
Sr0.4TiO3 films. However, the polarization, coercive electric
field and leakage current increased with decreasing content
of Sr. On the other hand, using appropriate oriented LSCO
buffer layers yields PSrT films with various textures.
Electrical properties of these textured films have been
investigated. Remanent polarization of (m00) preferred-oriented
Pb0.6Sr0.4TiO3 film is 32 mC/㎝2, which is larger than the
others. Pb0.6Sr0.4TiO3 thin films have also been deposited on
Pt/Ti/SiO2/Si by pulsedlaser deposition. The values of remanent
polarization and coercive field of the Pb0.6Sr0.4TiO3
films were estimated to be 21 mC/㎝2 and 43 kV/cm, respectively.
This indicates that the metal electrode show positive
effect on remanent polarization and is detrimental to coercive
electric field which is probably related to the fatigue
properties of ferroelectrics.
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