摘要:

A 3V 100ns read/write 256kb ferroelectric nonvolatile memory (FeRAM) is achieved with 1T/1C cells, novel reference cell circuits and cell plate circuits. The FeRAM is fabricated in 1.2um CMOS process with single Aluminum interconnection and Bi based layered perovskite ferroelectric material “Y-l” and has no fatigue even after 1012destructive read and re-write stress cycles.

ISSN:1058-4587    

DOI:10.1080/10584589508019349

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The characteristics of a field effect transistor with a lithium niobate gate insulator are reported. Shifts in the gate characteristics consistent with polarization switching have been observed. Comparisons with the results of some of the recently published theoretical models for ferroelectric gate transistors are made. Advantages and disadvantages of buffer layers in the gate structure are also discussed.

ISSN:1058-4587    

DOI:10.1080/10584589508019350

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this paper we describe an experimental study on ferroelectric non-volatile memory. The test devices using a MFMIS (metal-ferroelectric-metal-insulator-semiconductor) structure were developed for 1-Tr-type NDRO (non-destructive readout) memory. PZT (Lead-zirconate-titanate) and PT (lead-titanate) thin films were deposited on various bottom electrodes by solgel method. As electrodes, Pt, Pt/Ti, Pt/Ti/Ta and Pt/IrO2were deposited by RF magnetron sputtering. We found out that a variation in the electrodes caused drastic changes in the C-V characteristics and fatigue characteristics of MFMIS capacitors. The I-V characteristics of Pt/PZT/ Pt/SiO2/p-Si MFMIS FET showed a hysteresis loop and the direction of the loop corresponded to ferroelectric polarization in the PZT film. A 2.7 V memory window was achieved using a 6 V programming voltage. PZT thin films on Pt/IrO2electrodes showed no fatigue after 1012switching cycles.

ISSN:1058-4587    

DOI:10.1080/10584589508019351

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Bi4Ti3O12thin films were prepared on Pt/SiO2/Si(100) by metalorganic chemical vapor deposition (MOCVD).C-axis oriented Bi4Ti3O12thin films were grown on Pt/SiO2/Si (100) at 550°C. These films deposited directly on the substrates exhibit very rough surface morphology. However, a Bi4Ti3O12film with a Bi2Ti2O7buffer layer on Pt/SiO2/Si(100) exhibits very smooth morphology and has highc-axis orientation. This film shows remanent polarization of 0.6 μC/cm2, coercive field of 13 kV/cm and dielectric constant of 180. MFIS and MFMIS structures which were NDRO ferroelectric memory devices were fabricated using the Bi4Ti3O12films by MOCVD. In C-V measurement, memory windows by remanent polarization were shown in these structures. When Pt/IrO2/poly-Si was used as a floating gate, some improvements in C-V characteristics were obtained.

ISSN:1058-4587    

DOI:10.1080/10584589508019352

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The electric field emanating from the surface of a poled ferroelectric can control the conduction properties of an overlying semiconducting film; this combination of materials can thus serve as a non-destructive readout, non-volatile memory device. Here we will describe a variety of experimental studies of these devices designed to probe the physics of their operation. The experimental systems included sputtered, n-type semiconductor (SC) films of In2O3and ZnO deposited on bulk PLZT ferroelectrics (FE) and thin PZT FE films. Two distinctly different types of device response were measured in this study; in the first, the change in SC film conductance observed in the remanent FE state is in the direction expected from the remanent polarization vector in the ferroelectric. In the second, typically seen in thin film FE devices, the opposite behavior is observed. We find that these two general cases of behavior, including the observed variations of the SC film conductances and carrier mobilities, can be described by a general model which takes into account not only the FE displacement vector, but also charge injected from the semiconductor into the ferroelectric during biasing of the gate.

ISSN:1058-4587    

DOI:10.1080/10584589508019353

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We have studied partial switching characteristics of ferroelectric PZT thin films prepared by sol-gel technique for adaptive-learning MFSFET (Metal/Ferroelectrics/Semi-conductor Field Effect Transistor)applications. In this application, learning or initialization process can be realized by gradual reversal of polarization of the ferroelectric gate insulators. It is demonstrated that the polarization of PZT films can be gradually reversed by applying positive pulses to the MFM (Metal/ Ferroelectrics/Metal) capacitors and can be restored by negative short applying as the same.

ISSN:1058-4587    

DOI:10.1080/10584589508019354

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Investigations of materials interactions that complicate the integration of PZT ferroelectric capacitors into CMOS technologies are discussed. These include interactions within the Pt/Ti electrodes structure, the reactions of sol-gel deposited PZT during crystallization with various underlying dielectrics (SiO2, Si3N4, Al2O3, and TiO2), and the impact of other integrated circuit processes on fabricated capacitors.

ISSN:1058-4587    

DOI:10.1080/10584589508019355

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The feasibility of integrating ferroelectric thin films with silicon CMOS technology was investigated by processing a ferroelectric process evaluation module which contains ferroelectric and CMOS test structures and some memory cells. The smallest cells have a ferroelectric capacitor (FECAP) of 25 μm2. The FECAPs were made with Pt/Ti electrodes and with Pb(Zr,Ti)O3deposited by a modified sol-gel technique or by organometallic chemical vapour deposition. The back-end processing includes the insulation and interconnection of the FECAPs and the MOS transistors. The ferroelectric processing has only a slight influence on the CMOS properties. The properties of the FECAPs improve significantly by an additional anneal in oxygen. Both CMOS and FECAP properties allow a proper functioning of the memory cells. These can be reliably operated at supply voltages as low as 3 V and pulse widths down to 20 ns. The endurance of the memory cells exceeds 1013read/write cycles.

ISSN:1058-4587    

DOI:10.1080/10584589508019356

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Sol-gel derived lead zirconate titanate (PZT) thin films were deposited onto monolithic Pt bottom electrodes which used Ti interlayers for Pt adhesion on thermally oxidized ⟨111⟩ Si. The rf-sputter deposited Pt/Ti films were annealed at 400° – 600°C for 15 minutes. Atomic Force Microscopy (AFM) was used to analyze the Pt surface features. Transmission Electron Microscopy (TEM), transmission electron diffraction, scanning transmission electron microscopy (STEM), and scanning electron microscopy (SEM) were used to investigate the microstructure of PZT films crystallized onto these electrodes. RT-66A testing was conducted to evaluate the electrode performance of the Pt/PZT/Pt structure devices. It was found that the lower temperature bottom electrode anneal created a more dense, smaller grained nucleated PZT film.

ISSN:1058-4587    

DOI:10.1080/10584589508019357

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Lead-Zirconate-Titanate (PZT) capacitors were built and tested. The devices consist of a monolithic Pt back electrode, ferroelectric PZT film deposited by the sol-gel method, a patterned Pt top electrode, and a Spin-On-Glass (SOG) passivation layer to protect as well as aid in flip chip bonding. Two commercial SOG solutions are used and compared in this paper, a phosphosilicate and a methylsiloxane.

ISSN:1058-4587    

DOI:10.1080/10584589508019358

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor