A study of polarization effects in metal-ferroelectric-oxide-semiconductor capacitors

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PbTiO3 is a ferroelectric perovskite semiconductor with favorable electronic and optical properties, making it suitable for a wide range of applications, including photo-catalysis and (opto)electronic devices. Despite its relevance, an accurate ab initio description of the optical absorption spectrum and of the impact of ferroelectric distortion on the excitonic properties is still lacking. We combine G0W0 and Bethe–Salpeter equation calculations to investigate the electronic and optical properties of PbTiO

Junctions between p ‐ and n ‐doped semiconductors are ubiquitous in modern electronic devices and circuits. However, the tendency toward ‘natural’ defect doping (i.e., a fixed majority carrier polarity) has made the realization of pn ‐junctions between 2D/layered chalcogenide semiconductors challenging. Here, the formation of high‐quality, electrically active lateral junctions between Bi‐doped n ‐type SnSe and p ‐type SnS is demonstrated via a two‐step growth process, building on the successful integration

Platinum/tantalum/silicon ohmic contacts were designed, fabricated and characterized to withstand high-temperature post-processing: the ohmic behavior was maintained after 1 h annealing, at temperatures up to 850 degrees C in an oxidizing environment. A LPCVD silicon nitride layer was added to passivate the contacts from oxidation and concentrated wet hydrofluoric acid (HF 49%) process steps; the later being widely used for the release of free-standing MEMS structures. The linear Transfer Length Method (TLM

We demonstrate a concurrent polarization-retrieval algorithm based on a multi-heterodyne scanning near-field optical microscopy (MHSNOM) measurement system. This method relies on calibration of the polarization properties of the MH-SNOM using an isotropic region of the sample in the vicinity of the nanostructures of interest. We experimentally show the effectiveness of the method on a silicon form-birefringent grating (FBG) with significant polarization diversity. Three spatial dimensional near-field measur

Silicon heterojunction solar cells have high open-circuit voltages thanks to excellent passivation of the wafer surfaces by thin intrinsic amorphous silicon (a-Si:H) layers deposited by plasma-enhanced chemical vapor deposition (PECVD). By using in-situ plasma diagnostics and ex-situ film characterization, we show that the best a-Si:H films for passivation are produced from deposition regimes close to the amorphous-to-crystalline transition. Based upon this finding, layers deposited in a large-area very hig

This paper reports on a device capable of electrical cell lysis and evaluation of lysis efficiency in continuous flow using dielectrophoretic cell sorting. The device uses an innovative design, called liquid electrodes, to perform both cell lysis and cell sorting. A study of the cell position after sorting shows a very efficient lysis when a voltage of 55 Vpp is applied, whereas a voltage of 28Vpp does not induce any lysis.

The development of a particular etching recipe involving two sequences of a Deep Reactive Ion Etching followed by an isotropic etching step for the realization of 3D stacked arrays of fins and nanowires on bulk silicon is reported. Such a recipe can be used among the new processes and designs developed to control the shape and formation of such 3D structures. Applications in microelectronics (stacked field effect transistors) and microsystems (arrays of MEMS resonators and photonic structures) are foreseen.

In this work, a detailed analysis of capacitance behavior of high voltage MOSFET (HV-MOS) e.g. LDMOS, VDMOS using device simulation is made. The impact of lateral non-uniform doping and drift region is separately analyzed. It is shown that the peaks in C-GD and C-GS capacitances of HV-MOS originate from lateral non-uniform doping. The drift region decreases the C-GD capacitance and increases the peaks in CGS and also gives rise to peaks in C-GG capacitances increasing with higher drain bias. It is also show

In a molecular semiconductor, the carrier is dressed with a polarization cloud that we treat as a quantum field of Frenkel excitons coupled to it. The consequences of the existence of this electronic polaron on the dynamics of an extra charge in a material like pentacene can thus be evaluated

Zinc oxide (ZnO) is a material that belongs to the family of Transparent Conductives Oxides (TCO). Its non-toxicity and the abundant availability in the Earth's crust of its components make it an ideal candidate as electrical transparent contact for thin-film amorphous and/or microcrystalline silicon solar cells. The Low-Pressure Chemical Vapour Deposition (LP-CVD) method allows one to obtain rough ZnO layers, which can effectively scatter the light that passes through them. This high scattering capacity in

The state of the art of thin-film pyroelectric infrared (IR) detectors is reviewed covering device physics, material performance, micro-fabrication and device examples. Emphasis is given to special issues related to thin films, such as small heat capacities and the substrate influence on the pyroelectric properties. For the latter, an overview of the hitherto reported values is given. Examples of micromachined IR detectors based on pyroelectric thin films are described. The ultimate limit of micromachined t

Capacitors in metal-insulator-metal structure have been fabricated with different bottom electrodes. It has been found that the observed losses are enormous at gigahertz frequencies unless due care is taken not only for the conductivity of the bottom electrode but also its thickness. Very thin bottom electrodes (thickness similar to 100 nm) modify the dielectric response substantially and major loss contributions arise from the substrate, the electrode resistance, and the contacts. A simple approach is sugg

It was recently suggested, basing on the analysis of a wide range of macroscopic experimental results([1-4]), that fatigue in ferroelectric thin film capacitors, particularly in the case of PZT with metallic electrodes (Pt), must be related to the freezing of polarisation domains where the dielectric properties of the lattice remain nearly unchanged and the orientation of the locked domains can show a strong preferential direction. According to these results it was also possible to propose a simple method t

The self-polarization effect is investigated in Pb(Zr,Ti)O-3 (PZT) thin films deposited by sol-gel and magnetron sputtering techniques. The effective piezoelectric coefficient of as-grown films, which is proportional to their initial polarization (self-polarization), is measured by a sensitive interferometric technique as a function of the annealing temperature, PZT composition, film thickness and bottom electrode material. The results indicate that the films are self-polarized by an internal bias field upo

This paper examines the responses of four different types of shielded conduits to a direct lightning strike. The conduits are buried in the ground and run between two shielded enclosures, one of which is struck by lightning. An induced current flows on the conduit and this induces a voltage on the inner wires within the shield. Using a simple resistive model, this voltage is estimated and the effectiveness of the shielding provided by the various conduits is determined. A key element in the calculations is

We give topological criteria for the convexity and the concavity of a current or a voltage in a resistive circuit, as a function of a source voltage or current, when the nonlinear resistor characteristics are all either convex or concave. When the criteria are satisfied, all circuits with the same structure will have a convex, or all will have a concave transfer characteristic. The application of the criterion to ladder circuits leads to explicit and easily verifyable conditions.

This thesis deals with the monolithic integration of long wavelength (1.3-1.55 µm) p-i-n photodiodes with HEMT field effect transistors for the realization of wide bandwidth OEIC receivers for lightwave communication systems. Part of this work was carried out in collaboration with the Laboratory for Electromagnetic Fields and Microwave Electronics (IFH) of the ETH-Zürich. The p-i-n photodiode structure consisting of a n+-InP lower contact layer, a 1 µm undoped InGaAs absorption layer and a 100 nm p+-InGaAs

Piezoelectric membranes consisting of PbZrxTi1-xO3 (PZT) films on silicon diaphragms have been fabricated, investigated, and applied for micromotors. The PZT films were deposited by sputtering and sol gel techniques. Resonance amplitudes of up to 1000 nm/V have been measured for 16 mu m thick, 2 mm diameter membranes with 0.6 mu m PZT. The PZT films show a preferred direction of polarization, which seems to depend on the deposition technique. Membranes of 4 mm diameter have been successfully applied as a vi

A model for the calculation of lightning-induced voltages is presented allowing the assessment of the effect of corona when power distribution lines are illuminated by lightning electromagnetic fields. It is shown that, as far as corona can be described by means of an increase of capacitance after the voltage has reached a threshold value, corona can produce an increase in the peak amplitude of the induced voltage. An explanation of this result is given. The need for experimental results to test this theore

Particulate contamination produced during plasma-assisted deposition of amorphous silicon devices can be responsible for reduced quality and yield. The threshold for powder formation imposes an upper limit on the radio frequency (rf) power and hence the deposition rate. In this work, the parallel-plate capacitor discharge volume is illuminated and global, spatio-temporal powder dynamics are recorded by CCD camera for analysis. The onset of powder production is determined visually and from observed modificat

A study of polarization effects in metal-ferroelectric-oxide-semiconductor capacitors

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Coupling between ferroelectric distortions and excitonic properties in PbTiO3

Single‐Crystalline Lateral p ‐SnS/ n ‐SnSe van der Waals Heterostructures by Vapor Transport Growth with In Situ Bi Doping

Fabrication and formation of Ta/Pt-Si ohmic contacts applied to high-temperature Through Silicon Vias (TSVs)

Concurrent polarization retrieval in multiheterodyne scanning near-field optical microscopy: validation on silicon formbirefringent grating

21% efficiency silicon heterojunction solar cells produced with very high frequency PECVD

Cell sorting by dielectrophoresis for evaluation of lysis efficiency in continuous flow

3D stacked arrays of fins and nanowires on bulk silicon

Impact of lateral non-uniform doping and hot carrier degradation on capacitance behavior of high voltage MOSFETs

The impact of molecular polarization on the electronic properties of molecular semiconductors

L'oxyde de zinc par dépôt chimique en phase vapeur comme contact électrique transparent et diffuseur de lumière pour les cellules solaires

Micromachined infrared detectors based on pyroelectric thin films

The effect of bottom electrode on the performance of thin film based capacitors in the gigahertz region

Microscopic observation of "region by region" polarisation domains freezing during fatigue of the Pt-PZT-Pt system

Self-polarization effect in Pb(Zr,Ti)O-3 thin films

Estimates of lightning-induced voltage stresses within buried shielded conduits

Convexity of Resistive Circuit Characteristics

Photorécepteurs 1,3-1,55 µm obtenus par intégration monolithique de photodiodes p-i-n et de transistors HEMT

Fabrication and characterization of PZT thin films for micromotors

Influence of corona on lightning-induced voltages on overhead power lines

Powder Dynamics in Very High-Frequency Silane Plasmas