MIS and MFIS Devices: DyScO$_{3 }$ as a gate-oxide and buffer-layer

Metal-Ferroelectric-Insulator-Semiconductor (MFIS) structure is of importance in nonvolatile memories, as insulating buffer layer that prevents interdiffusion between the ferroelectric (FE) and the Si substrate. However, insulating layer has some disadvantages \textit{viz}. generation of depolarization field in FE film and increase of operation voltage. To overcome this, it is important to find a FE with low $\varepsilon _{r}$ (compared to normal FE) and an insulating buffer layer with high $\varepsilon _{r }$ (compared to $\varepsilon _{r}$ = 3.9 of SiO$_{2})$. High-k materials \textit{viz}. LaAlO$_{3}$, SiN, HfO$_{2}$, HfAlO etc. have been studied as buffer layers in the MFIS structures and as gate-oxide in metal-insulator-silicon (MIS). Recently, a novel gate dielectric material, DyScO$_{3}$ was considered and studies indicate that crystallization temperature significantly increased and the film on Si remained amorphous even at 1000\r{ }C annealing. Considering the requirements on crystallization temperature, $\varepsilon _{r}$, electrical stability for high-$k $buffer layers, DyScO$_{3}$ seems to be very promising for future MFIS device applications. Therefore, the evaluations of MOCVD grown DyScO$_{3}$ as gate-oxide for MIS and the buffer layers for Bi$_{3.25}$La$_{0.75}$Ti$_{3}$O$_{12}$ based MFIS structures are presented.