Impact of Backend Processing on Integrated Ferroelectric Capacitor Characteristics

1993 ◽  
Vol 310 ◽  
Author(s):  
P.D. Maniar ◽  
R. Moazzami ◽  
R.E. Jones ◽  
A.C. Campbell ◽  
C.J. Mogab
Keyword(s):  
Leakage Current ◽  
Sol Gel ◽  
Low Pressure ◽  
Cmos Process ◽  
Ferroelectric Capacitor ◽  
Standard Cmos Process ◽  
Order Of Magnitude ◽  
Pressure Hydrogen

AbstractIntegration of a ferroelectric capacitor module in a standard CMOS process subjects the ferroelectric to various ambients during backend processing, some of which can render the ferroelectric essentially non-operational for NVRAM applications. Post-crystallization processing of sol-gel deposited integrated ferroelectric PZT capacitors in the presence of hydrogen-containing, reducing ambients is observed to degrade the nonvolatile polarization. Low-pressure hydrogen anneals at temperatures as low as 200°C substantially degrade the nonvolatile polarization while the DRAM polarization remains roughly constant. Leakage current drops by one order of magnitude and fatigue is accelerated. A ferroelectric capacitor module can be integrated with minimal degradation with careful modifications in the backend processing.

Improved Electrical Properties of BaTiO3 – coated CaCu3Ti4O12 Dielectrics

2012 ◽  
Vol 1454 ◽  
pp. 75-80
Author(s):  
Hui Eun Kim ◽  
Sung Yun Lee ◽  
Sang-Im Yoo
Keyword(s):  
Solid State ◽  
Electrical Properties ◽  
Dielectric Loss ◽  
Leakage Current ◽  
Sol Gel ◽  
Dielectric Constants ◽  
Order Of Magnitude ◽  
Ccto Sample ◽  
State Mixing ◽  
Large Improvement

ABSTRACTWe report a significant improvement in the electrical properties of CaCu3Ti4O12 (CCTO) dielectrics by the BaTiO3 (BTO) additive. The addition of BTO to CCTO was performed using two different methods of a solid-state mixing and a sol-gel coating. Compared with pure CCTO ceramics (εr ∼ 52,000 and tanδ ∼ 0.38 at 100 kHz), BTO-added CCTO samples commonly showed a large improvement in the dielectric loss property although their dielectric constants were depressed around one order of magnitude; εr ∼ 5900 and tanδ ∼0.05 for 5 mol% BTO-coated CCTO sample and εr ∼ 4,075 and tanδ ∼ 0.02 for 5 mol% BTO-mixed CCTO sample. In addition, BTO-coated CCTO samples showed relatively lower leakage current than those of BTO-mixed CCTO samples, implying that the sol-gel coating is more effective for improving the electrical properties of CCTO.

Novel Chain Stack Capacitor for 32Mb FeRAM and Beyond

2002 ◽  
Vol 748 ◽  
Author(s):  
R. Bruchhaus ◽  
T. Ozaki ◽  
U. Ellerkmann ◽  
J. Lian ◽  
Y. Kumura ◽  
...  
Keyword(s):  
Bottom Electrode ◽  
Fatigue Behavior ◽  
Ferroelectric Material ◽  
Small Cell ◽  
High Density ◽  
Cmos Process ◽  
Cell Design ◽  
Ferroelectric Capacitor ◽  
Standard Cmos Process ◽  
Sputter Deposited

ABSTRACTFor high density FeRAM devices small cell sizes are essential. The combination of the capacitor on plug (COP) structure with the Chain FeRAM™ cell design is used to develop a 32Mb FeRAM. Based on a 0.2 μm standard CMOS process a silicide capped polysilicon plug is used to contact the bottom electrode of the ferroelectric capacitor to the transistor. The barrier contact to the plug is formed by IrO2/Ir and a sputter deposited PZT (40/60) is used as ferroelectric material. The function of SrRuO3 (SRO) layers at the electrode/PZT interfaces is described in more detail. Double sided SRO results in slightly lower coercive voltage and imprint behavior compared to capacitors without SRO. Double sided SRO is essential to achieve excellent fatigue behavior measured up to 1×1011 switching cycles.

Fabrication of Monolithic Integrated Bimaterial Resonant Uncooled IR Sensor

2013 ◽  
Vol 543 ◽  
pp. 176-179 ◽  
Author(s):  
D.Q. Zhao ◽  
Xia Zhang ◽  
P. Liu ◽  
F. Yang ◽  
C. Lin ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Hole Mobility ◽  
Micro Electro Mechanical System ◽  
Cmos Process ◽  
Standard Cmos Process ◽  
Ir Sensor ◽  
Cantilever Structure ◽  
Cmos Mems ◽  
On Chip ◽  
Micro Cantilever

In this work we studied the fabrication of a monolithic bimaterial micro-cantilever resonant IR sensor with on-chip drive circuits. The effects of high temperature process and stress induced performance degradation were investigated. The post-CMOS MEMS (micro electro mechanical system) fabrication process of this IR sensor is the focus of this paper, starting from theoretical analysis and simulation, and then moving to experimental verification. The capacitive cantilever structure was fabricated by surface micromachining method, and drive circuits were prepared by standard CMOS process. While the stress introduced by MEMS films, such as the tensile silicon nitride which works as a contact etch stopper layer for MOSFETs and releasing stop layer for the MEMS structure, increases the electron mobility of NMOS, PMOS hole mobility decreases. Moreover, the NMOS threshold voltage (Vth) shifts, and transconductance (Gm) degrades. An additional step of selective removing silicon nitride capping layer and polysilicon layer upon IC area were inserted into the standard CMOS process to lower the stress in MOSFET channel regions. Selective removing silicon nitride and polysilicon before annealing can void 77% Vth shift and 86% Gm loss.

scholarly journals Photocatalytic Activity Enhancement of Low-pressure Cold-Sprayed TiO2 Coatings Induced by Long-term Water Vapor Exposure

2021 ◽  
Author(s):  
Seremak Wioletta ◽  
Baszczuk Agnieszka ◽  
Jasiorski Marek ◽  
Gibas Anna ◽  
Winnicki Marcin
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Water Vapor ◽  
Sol Gel ◽  
Low Pressure ◽  
Oxygen Depletion ◽  
Amorphous Structure ◽  
Industrial Applications ◽  
Additional Parameter

AbstractThis work shows that the titanium dioxide coatings obtained by low-pressure cold gas spraying with the use of the sol–gel amorphous TiO2 powder are characterized by photocatalytic activity despite their partial amorphous content. Moreover, the research outcome suggests that the decomposition rate of organic pollutants is enhanced after long-term exposure to moisture. The condensation humidity test is not detrimental to the continuity and integrity of the coating, but the phase composition of coatings changes—with the exposure to water vapor, the portion of the amorphous phase crystallizes into brookite. The mechanism responsible for the conversion of amorphous TiO2 into brookite is attributed to the water-driven dissolution and reprecipitation of TiO6 octahedra. It has been shown that an additional parameter necessary for the stabilization of the brookite is the oxygen depletion of the amorphous structure of titanium dioxide. Considering the results presented in this paper and the advantages of a portable, low-pressure cold spray system for industrial applications, it is expected that TiO2 coatings produced from a sol–gel feedstock powder can be further developed and tested as efficient photocatalysts.

The Effect of RuO2/Pt Hybrid Bottom Electrode Structure on The Microstructure and Ferroelectric Properties of Sol-Gel Derived PZT Thin Films

1997 ◽  
Vol 493 ◽  
Author(s):  
Seung-Hyun Kim ◽  
J. G. Hong ◽  
J. C. Gunter ◽  
H. Y. Lee ◽  
S. K. Streiffer ◽  
...  
Keyword(s):  
Thin Films ◽  
Leakage Current ◽  
Bottom Electrode ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Chemical Solution ◽  
Electrode Structure ◽  
Solution Deposition ◽  
Pzt Thin Films ◽  
Chemical Solution Deposition Method

ABSTRACTFerroelectric PZT thin films on thin RuO2 (10, 30, 50nm)/Pt hybrid bottom electrodes were successfully prepared by using a modified chemical solution deposition method. It was observed that the use of a lOnm RuO2Pt bottom electrode reduced leakage current, and gave more reliable capacitors with good microstructure compare to the use of thicker RuO2/Pt bottom electrodes. Typical P-E hysteresis behavior was observed even at an applied voltage of 3V, demonstrating greatly improved remanence and coercivity. Fatigue and breakdown characteristics, measured at 5V, showed stable behavior, and only below 13-15% degradation was observed up to 1010 cycles. Thicker RuO2 layers resulted in high leakage current density due to conducting lead ruthenate or PZT pyrochlore-ruthenate and a rosette-type microstructure.

Photo-induced Large Area Growth Of Dielectrics With Excimer Lamps

2000 ◽  
Vol 617 ◽  
Author(s):  
Ian W. Boyd ◽  
Jun-Ying Zhang
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Low Temperature ◽  
Leakage Current ◽  
Sol Gel ◽  
Low Dielectric Constant ◽  
Large Area ◽  
Excimer Lamp ◽  
Low Dielectric ◽  
Current Densities

AbstractIn this paper, UV-induced large area growth of high dielectric constant (Ta2O5, TiO2and PZT) and low dielectric constant (polyimide and porous silica) thin films by photo-CVD and sol-gel processing using excimer lamps, as well as the effect of low temperature LW annealing, are discussed. Ellipsometry, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), UV spectrophotometry, atomic force microscope (AFM), capacitance-voltage (C-V) and current-voltage (I-V) measurements have been employed to characterize oxide films grown and indicate them to be high quality layers. Leakage current densities as low as 9.0×10−8 Acm−2 and 1.95×10−7 Acm−2 at 0.5 MV/cm have been obtained for the as-grown Ta2O5 films formed by photo-induced sol-gel processing and photo-CVD. respectively - several orders of magnitude lower than for any other as-grown films prepared by any other technique. A subsequent low temperature (400°C) UV annealing step improves these to 2.0×10−9 Acm−2 and 6.4× 10−9 Acm−2, respectively. These values are essentially identical to those only previously formed for films annealed at temperatures between 600 and 1000°C. PZT thin films have also been deposited at low temperatures by photo-assisted decomposition of a PZT metal-organic sol-gel polymer using the 172 nm excimer lamp. Very low leakage current densities (10−7 A/cm2) can be achieved, which compared with layers grown by conventional thermal processing. Photo-induced deposition of low dielectric constant organic polymers for interlayer dielectrics has highlighted a significant role of photo effects on the curing of polyamic acid films. I-V measurements showed the leakage current density of the irradiated polymer films was over an order of magnitude smaller than has been obtained in the films prepared by thermal processing. Compared with conventional furnace processing, the photo-induced curing of the polyimide provided both reduced processing time and temperature, A new technique of low temperature photo-induced sol-gel process for the growth of low dielectric constant porous silicon dioxide thin films from TEOS sol-gel solutions with a 172 nm excimer lamp has also been successfully demonstrated. The dielectric constant values as low as 1.7 can be achieved at room temperature. The applications investigated so far clearly demonstrate that low cost high power excimer lamp systems can provide an interesting alternative to conventional UV lamps and excimer lasers for industrial large-scale low temperature materials processing.

scholarly journals Integration Of Surface Micromachined Polysilicon Mirrors And A Standard Cmos Process

2005 ◽  
Author(s):  
M. Fischer ◽  
M. Nagele ◽  
D. Eichner ◽  
C. Schollhorn ◽  
R. Strobel
Keyword(s):  
Cmos Process ◽  
Standard Cmos Process
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