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FeRAM and MRAM Technologies
Published in Simon Deleonibus, Electronic Device Architectures for the Nano-CMOS Era, 2019
Figure 1 shows the key components and data storing mechanisms of FeRAM and MRAM devices. The ferroelectric capacitor shown in Fig. 1 (a) is used as a memory cell for FeRAM. The two remanent polarization directions in the capacitor’s ferroelectric film create the two memory states. Polarization direction is switched by applying programming voltage between the electrodes. Remanent polarization is caused by the movement of atoms that compose ferroelectricity. Stored data is read by detecting the polarization reversal or non-reversal current of a ferroelectric capacitor when the reading voltage is applied between the electrodes.
Ferroelectric, Piezoelectric Mechanism and Applications
Published in Journal of Asian Ceramic Societies, 2022
Arun Singh, Shagun Monga, Neeraj Sharma, K Sreenivas, Ram S. Katiyar
Conventionally, a metal–ferroelectric–semiconductor (MFS) thin film structure can be used as a nonvolatile memory device [36,37]. These devices utilize the basic characteristics of the remnant polarization of the ferroelectrics. The gate oxide of a MOS device is substituted by a ferroelectric film, and on applying voltage, an inversion/depletion layer is created, which stays unaffected even after the removal of the gate voltage due to the persistence of charges at the interface of film and semiconductor caused by the remanent polarization of the ferroelectric film[38]. The flat band shift and large interface state are created during the sputtering process, which makes the true ferroelectric field effect transistor difficult to realize. In the modified structure, a ferroelectric capacitor is used with a JFET (junction field effect transistor). Figure 13 illustrates the structure of the nonvolatile memory on GaAs substrate. The ferroelectric capacitor is used to bias the gate of the JFET, and even after the removal of the biasing voltage, the gate bias is non-zero because of the remanent polarization of the ferroelectric capacitor [39] Many ferroelectrics like LiNbO3 and PZT have high electro-optic coefficients.
Asymmetrical Doherty power amplifier using ferroelectric ceramics for linearity enhancement
Published in Electromagnetics, 2018
Shiwei Zhao, Xiaoqi Zhou, Yi Ren, Yuehang Xu
In the letter, utilizing features of both uneven power divider and ferroelectric capacitor, the novel asymmetrical DPA based on ferroelectric capacitor is proposed. The proposed uneven power divider replaced the conventional Wilkinson power divider in DPA, the uneven power divider ratio is achieved. Furthermore, the phase distortion at output of DPA can be corrected by tuning the phase of peak amplifier in DPA. The simulated and measured results of the proposed DPA show excellent linearity, which verify the feasibility of the method.