650V superjunction MOSFET using universal charge balance concept through drift region

In the ideal case, superjunction (SJ) drift regions theoretically exhibit a linear relationship between specific-on resistance Ron,sp and blocking voltage VBR, but this requires perfect charge balance between the alternating n and p pillars. If any degree of imbalance exists, the relationship becomes quadratic, similar to a conventional drift region, although with somewhat improved performance. In this work, we analyze superjunction drift regions in 4H-SiC under realistic degrees of charge imbalance and show that, with proper design, a reduction in specific on-resistance of 2~10x is possible as long as the imbalance remains less than ±20%.

Download Full-text

Simulation Studies of a Trench MOS Device Structure with Small Figures of Merit

MATEC Web of Conferences ◽

10.1051/matecconf/201820803005 ◽

2018 ◽

Vol 208 ◽

pp. 03005

Author(s):

Junhong Li

Keyword(s):

Drift Region ◽

Charge Balance ◽

Device Structure ◽

High Permittivity ◽

Voltage Range ◽

Charge Imbalance ◽

Figures Of Merit ◽

Simulation Results ◽

Mos Device ◽

Gate Charge

We proposed a vertical high permittivity trench power MOS (HKTMOS) device with alternating N&P drift region and high permittivity (HK) trench sandwiched in between. The unique structure guarantees uniform potential distribution for wide voltage range at block state owing to both HK potential modulation effect and superjunction (SJ) charge balance. The specific on-resistance (Rons) of HKTMOS is in orders of magnitude lower than the SJ counterparts at the on state because of the strong accumulation effect brought by HK trench. Although the gate charge also significantly rises because of the accumulation, the figures of merit (FOM) of HKTMOS still reduces considerably than the SJ under same BV. An expression for FOM is derived demonstrating that the FOM of HKTMOS is proportional to the square of HK trench depth, which agrees on with simulation results well. The simulation results indicate that within the BV range of 500~2000V, the Rons and FOM of HKTMOS are in 1~2 orders of magnitude lower and 17.4%~44.1% of SJ, respectively under the same BV condition. Furthermore, HKTMOS also demonstrates better charge imbalance tolerance than SJ.

Download Full-text

An Innovated 80V-100V High-Side Side-Isolated N-LDMOS Device

MATEC Web of Conferences ◽

10.1051/matecconf/201820102003 ◽

2018 ◽

Vol 201 ◽

pp. 02003

Author(s):

Shao Ming Yangi ◽

Gene Sheu ◽

Ting Yao Chien ◽

Chieh Chih Wu ◽

Tzu Chieh Lee ◽

...

Keyword(s):

Lower Energy ◽

3D Structure ◽

Doping Profile ◽

Drift Region ◽

Charge Balance ◽

Device Structure ◽

High Side ◽

Oxide Ratio ◽

Buried Layer ◽

P Type

We used TCAD Synopsys 3D tools and device simulators to propose an innovative device structure of 80V-100V high-side NLDMOS by using the silicon to silicon-di-oxide ratio with side trench. The high-side can also be developed by placing an NBL structure which can deliver a high as over 200V isolation voltage. The 3D structure can clear see the optimized linear p-top and n-drift region have better charge balance with linear doping profile to get the benchmark breakdown voltage (BVdss) of 80V with on-resistance (Ron) as low as 130 mΩ-mm2 and 100V with on-resistance as low as 175 mΩ-mm2.The linear p-type buried layer using high dosage and lower energy to achieve the better SOA and higher isolation voltage. Optimized linear p-top and PBL can improve Ron by 32.5% compare to other 100V high side device which have done from reference.

Download Full-text

Super Field Plate Technique That Can Provide Charge Balance Effect for Lateral Power Devices Without Occupying Drift Region

IEEE Transactions on Electron Devices ◽

10.1109/ted.2020.2981264 ◽

2020 ◽

Vol 67 (5) ◽

pp. 2218-2222

Author(s):

Chunwei Zhang ◽

Haijun Guo ◽

Zhenxiang Chen ◽

Wenjing Yue ◽

Yang Li ◽

...

Keyword(s):

Drift Region ◽

Charge Balance ◽

Power Devices ◽

Field Plate ◽

Plate Technique

Download Full-text

Supramolecular Assembly of U(IV) Clusters and Superatoms

10.26434/chemrxiv.11860065 ◽

2020 ◽

Author(s):

Ian Colliard ◽

Gregory Morrosin ◽

Hans-Conrad zur Loye ◽

May Nyman

Keyword(s):

Quantum Dots ◽

Supramolecular Assembly ◽

Emergent Properties ◽

Organic Media ◽

Body Centered Cubic ◽

Cluster Anions ◽

Charge Balance ◽

Interpenetrating Networks ◽

Hierarchical Assembly ◽

Two Parameters

Superatoms are nanometer-sized molecules or particles that can form ordered lattices, mimicking their atomic counterparts. Hierarchical assembly of superatoms gives rise to emergent properties in superlattices of quantum-dots, p-block clusters, and fullerenes. Here, we introduce a family of uranium-oxysulfate cluster anions whose hierarchical assembly in water is controlled by two parameters; acidity and the countercation. In acid, larger LnIII (Ln=La-Ho) link hexamer (U6) oxoclusters into body-centered cubic frameworks, while smaller LnIII (Ln=Er-Lu &Y) promote linking of fourteen U6-clusters into hollow superclusters (U84 superatoms). U84 assembles into superlattices including cubic-closest packed, body-centered cubic, and interpenetrating networks, bridged by interstitial countercations, and U6-clusters. Divalent transition metals (TM=MnII and ZnII), with no added acid, charge-balance and promote the fusion of 10 U6 and 10 U-monomers into a wheel–shaped cluster (U70). Dissolution of U70 in organic media reveals (by small-angle Xray scattering) that differing supramolecular assemblies are accessed, controlled by TM-linking of U70-clusters.

Download Full-text

A First-Principles Computational Comparison of the Aqueous Anatase TiO2 (001) Interface and the Disordered, Fluorinated TiO2 Interface

10.26434/chemrxiv.7076816.v1 ◽

2018 ◽

Author(s):

Kyle Reeves ◽

Damien Dambournet ◽

Christel Laberty-Robert ◽

Rodolphe Vuilleumier ◽

Mathieu Salanne

Keyword(s):

Density Of States ◽

Density Functional ◽

Water Dissociation ◽

Water Molecules ◽

Chemical Doping ◽

Charge Balance ◽

Functional Theory ◽

Adsorption Of Water ◽

Properties Of Materials ◽

Computational Comparison

Chemical doping and other surface modifications have been used to engineer the bulk properties of materials, but their influence on the surface structure and consequently the surface chemistry are often unknown. Previous work has been successful in fluorinating anatase TiO2 with charge balance achieved via the introduction of Ti vacancies rather than the reduction of Ti. Our work here investigates the interface between this fluorinated titanate with cationic vacancies and a monolayer of water via density functional theory based molecular dynamics. We compute the projected density of states for only those atoms at the interface and for those states that fall within 1eV of the Fermi energy for various steps throughout the simulation, and we determine that the variation in this representation of the density of states serves as a reasonable tool to anticipate where surfaces are most likely to be reactive. In particular, we conclude that water dissociation at the surface is the main mechanism that influences the anatase (001) surface whereas the change in the density of states at the surface of the fluorinated structure is influenced primarily through the adsorption of water molecules at the surface.

Download Full-text

A First-Principles Computational Comparison of the Aqueous Anatase TiO2 (001) Interface and the Disordered, Fluorinated TiO2 Interface

10.26434/chemrxiv.7076816 ◽

2018 ◽

Author(s):

Kyle Reeves ◽

Damien Dambournet ◽

Christel Laberty-Robert ◽

Rodolphe Vuilleumier ◽

Mathieu Salanne

Keyword(s):

Density Of States ◽

Density Functional ◽

Water Dissociation ◽

Water Molecules ◽

Chemical Doping ◽

Charge Balance ◽

Functional Theory ◽

Adsorption Of Water ◽

Properties Of Materials ◽

Computational Comparison

Chemical doping and other surface modifications have been used to engineer the bulk properties of materials, but their influence on the surface structure and consequently the surface chemistry are often unknown. Previous work has been successful in fluorinating anatase TiO2 with charge balance achieved via the introduction of Ti vacancies rather than the reduction of Ti. Our work here investigates the interface between this fluorinated titanate with cationic vacancies and a monolayer of water via density functional theory based molecular dynamics. We compute the projected density of states for only those atoms at the interface and for those states that fall within 1eV of the Fermi energy for various steps throughout the simulation, and we determine that the variation in this representation of the density of states serves as a reasonable tool to anticipate where surfaces are most likely to be reactive. In particular, we conclude that water dissociation at the surface is the main mechanism that influences the anatase (001) surface whereas the change in the density of states at the surface of the fluorinated structure is influenced primarily through the adsorption of water molecules at the surface.

Download Full-text

Adsorption of Carbon Monoxide on Pd/SiO2/Si(111) Studied by Core-Level Photoemission

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19981793 ◽

1998 ◽

Vol 63 (11) ◽

pp. 1793-1802 ◽

Cited By ~ 1

Author(s):

Zdeněk Bastl ◽

Tomáš Šarapatka

Keyword(s):

Carbon Monoxide ◽

Photoelectron Spectroscopy ◽

Co Adsorption ◽

Charge Balance ◽

Adsorption Activity ◽

Chemical States ◽

Adsorbed Co ◽

Pd Clusters ◽

Almost All ◽

P Type

X-Ray photoelectron spectroscopy (XPS) has been used to study the adsorption of carbon monoxide on Pd dispersed on oxidized Si(111) surface. A fraction of the deposited Pd diffusing at room temperature to the SiO2/Si interface increases with decreasing SiO2 thickness. For oxide layers thinner than ≈1 nm, almost all deposited Pd diffuses to SiO2/Si interface forming there Si silicide. Consequently, the amount of adsorbed CO is dependent on the thickness of the thermally grown SiO2 layer. Two different chemical states of adsorbed carbon atoms, the population of which depends on the amount of the Pd deposited, are observed in the C (1s) spectra of adsorbed CO. Adsorption activity of Pd clusters does not depend on whether n- or p-type Si is used. Comparison of the experimental Pd/CO concentration ratios with those calculated assuming several different modes of the Pd growth on SiO2/Si points to the pseudo-Stranski-Krastanow mode (flat clusters with incomplete condensation of the first layer) at 300 K. Changes in charge balance across the Pd/SiO2/Si interface caused by CO adsorption are discussed in terms of the surface photovoltage effect and work function variation.

Download Full-text