scholarly journals Current Tunnelling in MOS Devices with Al2O3/SiO2 Gate Dielectric

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
A. Bouazra ◽  
S. Abdi-Ben Nasrallah ◽  
M. Said ◽  
A. Poncet
Keyword(s):  
Dielectric Constant ◽  
Gate Dielectric ◽  
Oxide Thickness ◽  
Gate Leakage ◽  
Mos Devices ◽  
High K ◽  
Carrier Trap ◽  
High Dielectric ◽  
Very High ◽  
Tunnelling Current

With the continued scaling of the SiO2 thickness below 2 nm in CMOS devices, a large direct-tunnelling current flow between the gate electrode and silicon substrate is greatly impacting device performance. Therefore, higher dielectric constant materials are desirable for reducing the gate leakage while maintaining transistor performance for very thin dielectric layers. Despite its not very high dielectric constant (∼10), Al2O3 has emerged as one of the most promising high-k candidates in terms of its chemical and thermal stability as its high-barrier offset. In this paper, a theoretical study of the physical and electrical properties of Al2O3 gate dielectric is reported including I(V) and C(V) characteristics. By using a stack of Al2O3/SiO2 with an appropriate equivalent oxide thickness of gate dielectric MOS, the gate leakage exhibits an important decrease. The effect of carrier trap parameters (depth and width) at the Al2O3/SiO2 interface is also discussed.

Gate leakage properties of MOS devices with tri-layer high-k gate dielectric

2007 ◽  
Vol 47 (6) ◽  
pp. 937-943 ◽  
Author(s):  
W.B. Chen ◽  
J.P. Xu ◽  
P.T. Lai ◽  
Y.P. Li ◽  
S.G. Xu
Keyword(s):  
Gate Dielectric ◽  
Gate Leakage ◽  
Mos Devices ◽  
High K ◽  
High K Gate Dielectric

A low gate leakage current and small equivalent oxide thickness MOSFET with Ti/HfO2 high-k gate dielectric

2011 ◽  
Vol 88 (7) ◽  
pp. 1309-1311 ◽  
Author(s):  
C.H. Fu ◽  
K.S. Chang-Liao ◽  
Y.A. Chang ◽  
Y.Y. Hsu ◽  
T.H. Tzeng ◽  
...  
Keyword(s):  
Leakage Current ◽  
Gate Dielectric ◽  
Oxide Thickness ◽  
Gate Leakage Current ◽  
Equivalent Oxide Thickness ◽  
Gate Leakage ◽  
High K ◽  
High K Gate Dielectric

Scalability of MOCVD-deposited Hafnium Oxide

2003 ◽  
Vol 765 ◽  
Author(s):  
S. Van Elshocht ◽  
R. Carter ◽  
M. Caymax ◽  
M. Claes ◽  
T. Conard ◽  
...  
Keyword(s):  
Hafnium Oxide ◽  
Interfacial Layer ◽  
Gate Dielectric ◽  
Deposition Process ◽  
Oxide Thickness ◽  
Process Conditions ◽  
Primary Concern ◽  
Gate Electrode ◽  
K Value ◽  
High K

AbstractBecause of aggressive downscaling to increase transistor performance, the physical thickness of the SiO2 gate dielectric is rapidly approaching the limit where it will only consist of a few atomic layers. As a consequence, this will result in very high leakage currents due to direct tunneling. To allow further scaling, materials with a k-value higher than SiO2 (“high-k materials”) are explored, such that the thickness of the dielectric can be increased without degrading performance.Based on our experimental results, we discuss the potential of MOCVD-deposited HfO2 to scale to (sub)-1-nm EOTs (Equivalent Oxide Thickness). A primary concern is the interfacial layer that is formed between the Si and the HfO2, during the MOCVD deposition process, for both H-passivated and SiO2-like starting surfaces. This interfacial layer will, because of its lower k-value, significantly contribute to the EOT and reduce the benefit of the high-k material. In addition, we have experienced serious issues integrating HfO2 with a polySi gate electrode at the top interface depending on the process conditions of polySi deposition and activation anneal used. Furthermore, we have determined, based on a thickness series, the k-value for HfO2 deposited at various temperatures and found that the k-value of the HfO2 depends upon the gate electrode deposited on top (polySi or TiN).Based on our observations, the combination of MOCVD HfO2 with a polySi gate electrode will not be able to scale below the 1-nm EOT marker. The use of a metal gate however, does show promise to scale down to very low EOT values.

Fluoro-polymer functionalized graphene for flexible ferroelectric polymer-based high-k nanocomposites with suppressed dielectric loss and low percolation threshold

Nanoscale ◽  
2014 ◽  
Vol 6 (24) ◽  
pp. 14740-14753 ◽  
Author(s):  
Ke Yang ◽  
Xingyi Huang ◽  
Lijun Fang ◽  
Jinliang He ◽  
Pingkai Jiang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Percolation Threshold ◽  
High Dielectric Constant ◽  
Functionalized Graphene ◽  
Ferroelectric Polymer ◽  
Flexible Polymer ◽  
High K ◽  
High Dielectric

Fluoro-polymer functionalized graphene was synthesized for flexible polymer-based nanodielectrics. The resulting nanocomposites exhibit high dielectric constant, suppressed dielectric loss and low percolation threshold.

Scaling of Hafnium-based High-k Dielectrics

2007 ◽  
Vol 996 ◽  
Author(s):  
Dina H. Triyoso ◽  
Rama I. Hegde ◽  
Rich Gregory ◽  
David C. Gilmer ◽  
James K. Schaeffer ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Threshold Voltage ◽  
Tetragonal Phase ◽  
Minimum Thickness ◽  
Equivalent Thickness ◽  
K Value ◽  
Good Thermal Stability ◽  
Bilayer Films ◽  
High K ◽  
High Dielectric

AbstractIn this paper, various approaches to extend scalability of Hafnium-based dielectrics are reported. Among the three crystal phases of HfO2 (monoclinic, cubic and tetragonal), the tetragonal phase has been reported to have the highest dielectric constant. Tetragonal phase stabilization by crystallizing the thin HfO2 using a metal capping layer and by adding zirconium is demonstrated. The microstructure, morphology, optical properties and impurities of HfxZr1-xO2 dielectrics (for 0<x<1) are discussed. Subtle but important modification to high-k / Si interface characteristics resulting from addition of Zr into HfO2 is reported. To further boost the dielectric constant of hafnium-based dielectrics, incorporation of TiO2, which has been reported to have high dielectric constant, is explored. HfxZr1-xO2/TiO2 bilayer films were fabricated. 30 Å TiO2 films were deposited on a 5, 8, 12 or 15 Å HfxZr1-xO2 underlayer to determine the minimum thickness needed to maintain good thermal stability with Si substrate. CV and IV results indicated that 12-15 Å is the optimal thickness range for the HfxZr1-xO2 underlayer. A dielectric constant as high as 150 for TiO2 layer is extracted from TiO2 thickness series deposited on12 Å HfxZr1-xO2 underlayer. In addition to increasing the k-value of Hafnium-based dielectrics, it is important that the threshold voltage of these high-k devices is low. Here we report the use of thin Al2O3 capping layers to modulate PMOS threshold voltages. About 100 mV reduction in threshold voltage is achieved by capping HfO2 with a 5Å Al2O3 film. Finally, dielectric scaling by modifying the Si/high-k interfacial layer is attempted. Nitrogen incorporation into HfxZr1-xO2 is shown to be a simple and effective method to lower the capacitance equivalent thickness (CET) of Hafnium-based dielectrics.

scholarly journals High-K dielectric sulfur-selenium alloys

2019 ◽  
Vol 5 (5) ◽  
pp. eaau9785 ◽  
Author(s):  
Sandhya Susarla ◽  
Thierry Tsafack ◽  
Peter Samora Owuor ◽  
Anand B. Puthirath ◽  
Jordan A. Hachtel ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Metal Oxides ◽  
High Dielectric Constant ◽  
Dielectric Material ◽  
Dielectric Strength ◽  
Dielectric Materials ◽  
High K ◽  
Device Applications ◽  
High K Dielectric ◽  
High Dielectric

Upcoming advancements in flexible technology require mechanically compliant dielectric materials. Current dielectrics have either high dielectric constant, K (e.g., metal oxides) or good flexibility (e.g., polymers). Here, we achieve a golden mean of these properties and obtain a lightweight, viscoelastic, high-K dielectric material by combining two nonpolar, brittle constituents, namely, sulfur (S) and selenium (Se). This S-Se alloy retains polymer-like mechanical flexibility along with a dielectric strength (40 kV/mm) and a high dielectric constant (K = 74 at 1 MHz) similar to those of established metal oxides. Our theoretical model suggests that the principal reason is the strong dipole moment generated due to the unique structural orientation between S and Se atoms. The S-Se alloys can bridge the chasm between mechanically soft and high-K dielectric materials toward several flexible device applications.

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