High Mobilities in Organic Molecular Crystals

1999 ◽  
Vol 598 ◽  
Author(s):  
Jan Hendrik Schön ◽  
Steffen Berg ◽  
Christian Kloc ◽  
Bertram Batlogg
Keyword(s):  
Single Crystals ◽  
Electric Fields ◽  
Phonon Scattering ◽  
Effective Bandwidth ◽  
Hot Carrier ◽  
Organic Molecular Crystals ◽  
Electric Field Dependence ◽  
Hot Carrier Effects ◽  
High Electric Fields ◽  
Molecular Semiconductors

ABSTRACTThe charge transport in high quality single crystals of various organic molecular semiconductors is investigated. Band-like motion in delocalized states is observed in various polyacene and oligothiophene single crystals. The electric field dependence of the mobility is ascribed to acoustic phonon scattering. Furthermore, hot carrier effects can be observed at low temperatures and high electric fields. Band-like transport changes over to hopping motion when the effective bandwidth shrinks, i.e. at high temperatures or in crystallographic directions of small molecular orbital overlap.

Hot Carrier Effects in Deep Submicron Nmosfets

1996 ◽  
Vol 428 ◽  
Author(s):  
Abhijit Phanse ◽  
Samar Saha
Keyword(s):  
Electric Fields ◽  
Channel Length ◽  
Deep Submicron ◽  
Short Channel ◽  
Hot Carrier ◽  
Velocity Saturation ◽  
Substrate Current ◽  
Hot Carrier Effects ◽  
Saturation Effects ◽  
Channel Lengths

AbstractThis paper addresses hot-carrier related reliability issues in deep submicron silicon nMOSFET devices. In order to monitor the hot-carrier induced device degradation, the substrate current was measured for devices with varying channel lengths (20 um - 0.24 um) under various biasing conditions. Deep submicron devices experience velocity saturation of channel carriers due to extremely high lateral electric fields. To evaluate the effects of velocity saturation in the channel, the pinch-off length in the channel was extracted for all the devices of the target technology. It was observed that for very short channel devices, carriers in most of the channel experience velocity saturation and almost the entire channel gets pinched off. It is shown in this paper that for very short channel devices, the pinch-off length in the channel is limited by the effective channel length, and that velocity saturation effects are critical to the transport of channel carriers.

Evidence of Channel Mobility Anisotropy on 4H-SiC MOSFETs with Low Interface Trap Density

2019 ◽  
Vol 963 ◽  
pp. 473-478 ◽  
Author(s):  
Maria Cabello ◽  
Victor Soler ◽  
Daniel Haasmann ◽  
Josep Montserrat ◽  
Jose Rebollo ◽  
...  
Keyword(s):  
Electric Fields ◽  
Phonon Scattering ◽  
High Mobility ◽  
Interface State ◽  
Channel Mobility ◽  
Optical Phonon Scattering ◽  
Anisotropy Effect ◽  
State Densities ◽  
High Electric Fields ◽  
Small Anisotropy

In this work, we have evaluated 4° off-axis Si face 4H-SiC MOSFETs channel performance along both the [11-20] (perpendicular to steps) and [1-100] (parallel to steps) orientations, to evidence possible anisotropy on Si-face due to roughness scattering effect. Improved gate oxide treatments, allowing low interface state densities and therefore high mobility values, have been used on both NO and N2O annealed gate oxides. With these high channel mobility samples, a small anisotropy effect (up to 10%) can be observed at high electric fields. The anisotropy can be seen both at room and high temperatures. However, the optical phonon scattering is the dominant effect under these biasing conditions.

Study of Mobility Limiting Mechanisms in (0001) 4H and 6H-SiC MOSFETs

2011 ◽  
Vol 679-680 ◽  
pp. 595-598 ◽  
Author(s):  
Harsh Naik ◽  
T. Paul Chow
Keyword(s):  
Surface Roughness ◽  
Electric Fields ◽  
Phonon Scattering ◽  
Surface Roughness Scattering ◽  
High Electric Fields

To study the mobility limiting mechanisms in (0001) 4H-SiC and 6H-SiC MOSFETs, physics based modeling of the inversion mobility of has been done. Two very different limiting mechanisms have been found for 4H-SiC and 6H-SiC MOSFETs. The mobility in 6H-SiC MOSFETs is limited by phonon scattering while the 4H-SiC MOSFET mobility is limited by Coulombic at low electric fields and surface roughness scattering at high electric fields.

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