FABRICATIONS OF FERROELECTRIC-GATE FIELD-EFFECT-TRANSISTORS USING P(L)ZT FILMS

We report an approach to fabricate ferroelectric-gate field-effect-tra nsistors (FETs) using (PbLa)(ZrTi)O-3 (PLZT) films for memory and neur al network applications. First, we show the ferroelectric PLZT films c an be grown on Si substrates using a SrTiO3(STO) buffer layer. By usin g a relatively low-E ferroelectric PLZT film with a low Zr/Ti ratio of 30/70, a memory window of 0.6 V is obtained in the C-V characteristic s. Then, we report the fabrication of ferroelectric-gate FETs using PL ZT/STO/Si structures. It is shown that I-D(drain current)-V-G(gate vol tage) characteristics of STO/Si MISFET showed no hysteresis, whereas f erroelectric gate FETs using the PLZT/STO/Si structure showed a clear hysteresis loop due to the ferroelectric nature of the PLZT film. We a lso demonstrate the memory functions of the device.