Band Alignments of High-K Dielectrics on Si and Pt

1999 ◽  
Vol 592 ◽  
Author(s):  
J Robertson ◽  
E Riassi ◽  
J-P Maria ◽  
A I Kingon
Keyword(s):  
Conduction Band ◽  
Gate Dielectrics ◽  
Random Access ◽  
Leakage Currents ◽  
Band Offsets ◽  
Silicon Devices ◽  
High K ◽  
Band Alignments ◽  
High K Materials ◽  
High Dielectric

ABSTRACTMaterials with a high dielectric constant (K) such as tantalum pentoxide (Ta2O5) and barium strontium titanate (BST) are needed for insulators in dynamic random access memory capacitors and as gate dielectrics in future silicon devices. The band offsets of these oxides must be over 1 eV for both electrons and holes, to minimise leakage currents due to Schottky emission. We have calculated the band alignments of many high K materials on Si and metals using the method of charge neutrality levels. Ta2O5 and BST have rather small conduction band offsets on Si, because the band alignments are quite asymmetric. Other wide gap materials Al2O3, Y2O3, ZrO2 and ZrSiO4 are found to have offsets of over 1.5 eV for both electrons and holes, suggesting that these are preferable dielectrics. Zirconates such as BaZrO3 have wider gaps than the titanates, but they still have rather low conduction band offsets on Si. The implications of the results for future generations of MOSFETs and DRAMS are discussed.

Conduction band states of transition metal (TM) high-k gate dielectrics as determined from X-ray absorption spectra

2005 ◽  
Vol 45 (5-6) ◽  
pp. 827-830 ◽  
Author(s):  
G. Lucovsky ◽  
J.G. Hong ◽  
C.C. Fulton ◽  
N.A. Stoute ◽  
Y. Zou ◽  
...  
Keyword(s):  
Transition Metal ◽  
Absorption Spectra ◽  
Conduction Band ◽  
Gate Dielectrics ◽  
X Ray ◽  
High K ◽  
X Ray Absorption

scholarly journals Effect of Thickness and Temperature of SiO2 Layer on Leakage Currents in MOS Capacitor Materials with High Dielectric Constant by Involving the Charge Trap

2014 ◽  
Vol 15 (1) ◽  
pp. 1
Author(s):  
Fatimah A. Noor ◽  
Masturi Masturi ◽  
Mikrajuddin Abdullah ◽  
Khairurrijal Khairurrijal
Keyword(s):  
Leakage Current ◽  
Dielectric Material ◽  
Great Influence ◽  
Oxide Semiconductor ◽  
Electron Mass ◽  
Leakage Currents ◽  
Mos Capacitor ◽  
High K ◽  
Current Electron ◽  
High Dielectric

Modeling of the leakage current in a field-effect transistor metal-oxide-semiconductor (MOSFET) with high dielectric material has been developed by taking into account the effect of charge traps formed at the interface of high-k material/SiO2. Transmittance calculated using Airy wave function approach and involving the anisotropic electron mass and the effect of coupling between transverse and longitudinal energy represented by the speed of the electrons in the metal gate. Transmittance obtained is then used to calculate the leakage current in the structure of n+Poly-Si/HfSiOxN/trap/SiO2/p-Si for oxide voltage variations, temperature, and thickness of the SiO2. From the calculation that the leakage current decreases with decreasing of oxide voltage and increasing of the thickness of the oxide layer of SiO2. Also obtained that the temperature of the device does not give a great influence on the change of leakage current. Keywords: Leakage current, electron speed, charge traps

scholarly journals High-k Polymer Nanocomposite Materials for Technological Applications

2020 ◽  
Vol 10 (12) ◽  
pp. 4249
Author(s):  
Ganesh Shimoga ◽  
Sang-Youn Kim
Keyword(s):  
Polymer Nanocomposites ◽  
Gate Dielectrics ◽  
Field Effect Transistors ◽  
Polymer Nanocomposite ◽  
Tunable Capacitors ◽  
Contemporary World ◽  
Nanocomposite Polymer ◽  
Electro Optic ◽  
High K ◽  
High Dielectric

Understanding the properties of small molecules or monomers is decidedly important. The efforts of synthetic chemists and material engineers must be appreciated because of their knowledge of how utilize the properties of synthetic fragments in constructing long-chain macromolecules. Scientists active in this area of macromolecular science have shared their knowledge of catalysts, monomers and a variety of designed nanoparticles in synthetic techniques that create all sorts of nanocomposite polymer stuffs. Such materials are now an integral part of the contemporary world. Polymer nanocomposites with high dielectric constant (high-k) properties are widely applicable in the technological sectors including gate dielectrics, actuators, infrared detectors, tunable capacitors, electro optic devices, organic field-effect transistors (OFETs), and sensors. In this short colloquy, we provided an overview of a few remarkable high-k polymer nanocomposites of material science interest from recent decades.

scholarly journals Radiation Tolerance and Charge Trapping Enhancement of ALD HfO2/Al2O3 Nanolaminated Dielectrics

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 849
Author(s):  
Dencho Spassov ◽  
Albena Paskaleva ◽  
Elżbieta Guziewicz ◽  
Vojkan Davidović ◽  
Srboljub Stanković ◽  
...  
Keyword(s):  
Charge Trapping ◽  
Atomic Layer ◽  
Information Storage ◽  
Radiation Tolerance ◽  
Leakage Currents ◽  
High K ◽  
60Co Source ◽  
Retention Characteristics ◽  
High K Materials ◽  
High K Dielectric

High-k dielectric stacks are regarded as a promising information storage media in the Charge Trapping Non-Volatile Memories, which are the most viable alternative to the standard floating gate memory technology. The implementation of high-k materials in real devices requires (among the other investigations) estimation of their radiation hardness. Here we report the effect of gamma radiation (60Co source, doses of 10 and 10 kGy) on dielectric properties, memory windows, leakage currents and retention characteristics of nanolaminated HfO2/Al2O3 stacks obtained by atomic layer deposition and its relationship with post-deposition annealing in oxygen and nitrogen ambient. The results reveal that depending on the dose, either increase or reduction of all kinds of electrically active defects (i.e., initial oxide charge, fast and slow interface states) can be observed. Radiation generates oxide charges with a different sign in O2 and N2 annealed stacks. The results clearly demonstrate a substantial increase in memory windows of the as-grown and oxygen treated stacks resulting from enhancement of the electron trapping. The leakage currents and the retention times of O2 annealed stacks are not deteriorated by irradiation, hence these stacks have high radiation tolerance.

Optimizing MIM Device Electrical Properties. Impact of Bottom Electrodes and High K Materials

2008 ◽  
Vol 1108 ◽  
Author(s):  
Marceline Bonvalot ◽  
Christophe Vallée ◽  
Emmanuel Gourvest ◽  
Corentin Jorel ◽  
Patrice Gonon
Keyword(s):  
Work Function ◽  
Electrode Material ◽  
Oxygen Vacancies ◽  
Bottom Electrode ◽  
Leakage Currents ◽  
Capacitance Density ◽  
High K ◽  
High K Materials ◽  
High Work ◽  
Mim Capacitors

AbstractHigh quality MIM capacitors with improved capacitance density, low leakage currents and linear C(V) behaviour are the object of active research, with potential applications in CMOS, BICMOS and bipolar technologies as filters, analog to digital converters and related radio-frequency operating devices. Several high-k materials (Ta2O5, HfO2, Y2O3, Al2O3-HfTiO, HfON-SiO2) have been put on trial as possible candidates for SiO2 substitution which is required by the aggressive downscaling of electronic devices. Among those, HfO2- based materials seem to offer promising properties, combining a high chemical stability with Si and a high k value. However, HfO2 shows a strong ability to favour charge defects such as oxygen vacancies, which in turn affect the intrinsic properties of devices such as threshold voltage or leakage currents. These oxygen vacancies are actually thought to accumulate in the vicinity of the electrode, thus forming an oxidized interfacial layer and inducing a significant voltage linearity degradation of MIM capacitors.In this work, it will be shown that this oxide layer thickness can be strongly minimized by using appropriate bottom electrode material. Indeed, high work function materials can efficiently prevent oxygen vacancies charge stocking on their surface. Several MIM devices have been prepared based on HfO2, Al2O3 and SrTiO3 as dielectric materials, and TiN, WSi2.7 and Pt as bottom electrode material. All these devices have been fully characterized in terms of materials properties and electrical behaviour. These results have been analysed and show that a reduced dielectric thickness is preferred to achieve high capacitance density, but is also responsible for voltage linearity degradation. High work function electrode material can help improve this degraded linear behaviour, thanks to the formation of a reduced interfacial oxygen trap layer thickness. Leakage currents seem to be deeply correlated with the morphological state of the dielectric material, an amorphous state being obviously more efficient to prevent current pathways through grain boundaries.All these results will be presented in detail and discussed with regards to different models proposed in the literature to account for these data.

Atomic Structure, Band Offsets and Hydrogen in High K oxide:Silicon interfaces

2002 ◽  
Vol 747 ◽  
Author(s):  
J Robertson ◽  
P W Peacock
Keyword(s):  
Dielectric Constant ◽  
Electronic Structure ◽  
Atomic Structure ◽  
High Dielectric Constant ◽  
Dangling Bond ◽  
Charge Neutrality ◽  
Band Offsets ◽  
High K ◽  
Bulk Charge ◽  
High Dielectric

AbstractThe bonding, electronic structure and valence band offsets are calculated for various atomic models of interfaces between Si and high dielectric constant insulators ZrO2 and SrTiO3. A non-polar face of the oxide does not necessarily give a semiconducting interface, because of the need to fill Si dangling bond states on the Si side. This can be achieved by stoichiometry changes. Band offsets of semiconducting interfaces are generally the same as those found from bulk charge neutrality levels, indicating no dipole layers. Dipole layers are present at some configurations, where the offset is then changed by up to 1 eV. The states of hydrogen in the oxides are also considered.

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