CALCULATION OF THE ELECTRON DRIFT MOBILITY IN Cr2+:ZnS AND Cr2+:ZnSe MATERIALS BY RODE ITERATION MODEL

2010 ◽  
Vol 01 (04) ◽  
pp. 469-475 ◽  
Author(s):  
HADI ARABSHAHI
Keyword(s):  
Impurity Scattering ◽  
Electron Drift ◽  
Deformation Potential ◽  
Material Parameters ◽  
Free Carriers ◽  
Relaxation Time Approximation ◽  
Ionized Impurity Scattering ◽  
Different Temperatures ◽  
Iteration Model ◽  
Electron Drift Mobility

The results of electron drift velocity in Cr2+:ZnS , and Cr2+:ZnSe are calculated for different temperatures, free-electron concentrations and compositions. The two-mode nature of the polar optic phonons is considered jointly with deformation potential acoustic, piezoelectric, alloy and ionized-impurity scattering. Band non-parabolocity, admixture of p functions, arbitrary degeneracy of the electron distribution, and the screening effects of free carriers on the scattering probabilities are incorporated. The Boltzmann equation is solved by an iterative technique using the currently established values of the material parameters. The iterative results are in fair agreement with other recent calculations obtained using the relaxation-time approximation and experimental methods.

LOW-FIELD ELECTRON TRANSPORT PROPERTIES IN ZINCBLENDE AND WURTZITE GaN STRUCTURES USING AN ITERATION MODEL FOR SOLVING BOLTZMANN EQUATION

2009 ◽  
Vol 23 (10) ◽  
pp. 1359-1366 ◽  
Author(s):  
H. ARABSHAHI ◽  
A. A. MOWLAVI
Keyword(s):  
Electron Transport ◽  
Transport Properties ◽  
Impurity Scattering ◽  
Free Carriers ◽  
Low Field ◽  
Ionized Impurity Scattering ◽  
Iteration Model ◽  
Electron Transport Properties ◽  
Gan Crystal ◽  
Electron Drift Mobility

An iteration calculation has been carried out to study electron transport properties in zincblende and wurtzite GaN materials. The two-mode nature of the polar optic phonons is considered jointly with deformation potential acoustic, piezoelectric, ionized impurity scattering. Band non-parabolicity, admixture of p functions, arbitrary degeneracy of the electron distribution, and the screening effects of free carriers on the scattering probabilities are incorporated. Electron drift mobility in both zincblende and wurtzite GaN crystal structures are calculated for different temperature and doping dependencies. It is found that the electron mobility decreases monotonically as the temperature increases from 100 K to 600 K. The low temperature value of electron mobilty increases significantly with increasing doping concentration. The agreement of iterative results with the available experimental data is found to be satisfactory.

scholarly journals Simulation of the Impact of Ionized Impurity Scattering on the Total Mobility in Si Nanowire Transistors

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 124 ◽  
Author(s):  
Toufik Sadi ◽  
Cristina Medina-Bailon ◽  
Mihail Nedjalkov ◽  
Jaehyun Lee ◽  
Oves Badami ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Small Diameter ◽  
Golden Rule ◽  
Impurity Scattering ◽  
Boltzmann Transport ◽  
Nanowire Transistors ◽  
Scattering Mechanisms ◽  
Relaxation Time Approximation ◽  
Ionized Impurity Scattering ◽  
The Impact

Nanowire transistors (NWTs) are being considered as possible candidates for replacing FinFETs, especially for CMOS scaling beyond the 5-nm node, due to their better electrostatic integrity. Hence, there is an urgent need to develop reliable simulation methods to provide deeper insight into NWTs’ physics and operation, and unlock the devices’ technological potential. One simulation approach that delivers reliable mobility values at low-field near-equilibrium conditions is the combination of the quantum confinement effects with the semi-classical Boltzmann transport equation, solved within the relaxation time approximation adopting the Kubo–Greenwood (KG) formalism, as implemented in this work. We consider the most relevant scattering mechanisms governing intraband and multi-subband transitions in NWTs, including phonon, surface roughness and ionized impurity scattering, whose rates have been calculated directly from the Fermi’s Golden rule. In this paper, we couple multi-slice Poisson–Schrödinger solutions to the KG method to analyze the impact of various scattering mechanisms on the mobility of small diameter nanowire transistors. As demonstrated here, phonon and surface roughness scattering are strong mobility-limiting mechanisms in NWTs. However, scattering from ionized impurities has proved to be another important mobility-limiting mechanism, being mandatory for inclusion when simulating realistic and doped nanostructures, due to the short range Coulomb interaction with the carriers. We also illustrate the impact of the nanowire geometry, highlighting the advantage of using circular over square cross section shapes.

Analysis of Gate Oxide Nitridation Effect on SiC MOSFETs by Using Hall Measurement and Split C–V Measurement

2016 ◽  
Vol 858 ◽  
pp. 441-444 ◽  
Author(s):  
Masatoshi Tsujimura ◽  
Hidenori Kitai ◽  
Hiromu Shiomi ◽  
Kazutoshi Kojima ◽  
Kenji Fukuda ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Hall Mobility ◽  
Impurity Scattering ◽  
Gate Oxide ◽  
Trap Density ◽  
Oxide Semiconductor ◽  
Free Carriers ◽  
Scattering Mechanisms ◽  
Ionized Impurity Scattering ◽  
Similar Temperature

In this study, 4H–SiC inversion layers were experimentally evaluated by Hall and split C–V measurements, and scattering mechanisms related to gate oxide nitridation were analyzed. Three typical samples with different crystal plane directions and gate oxidation conditions were prepared, and their total trap density and Hall mobility were compared. Based on the temperature dependence of the Hall mobility, we found that scattering mechanisms differed for each sample. The sample C-face oxynitride which had a high nitrogen density at the metal–oxide–semiconductor (MOS) interface, showed a similar temperature dependency to that of ionized impurity scattering. This result suggests that high-density nitrogen acts as donors that supply free carriers and cause ionized impurity scattering, just like in a bulk crystal. In addition, the sample C-face wet has lowest influence of the Coulomb scattering because of the lowest temperature dependence of Hall mobility and the lowest total trap density.

Role of Neutral Impurity Scattering in the Analysis of Hall Data from ZnO and Other II-VI Materials

2007 ◽  
Vol 1035 ◽  
Author(s):  
Xiaocheng Yang ◽  
Chunchuan Xu ◽  
N. C. Giles
Keyword(s):  
Hall Mobility ◽  
Impurity Scattering ◽  
Polar Optical Phonon ◽  
Deformation Potential ◽  
Concentration Data ◽  
Relaxation Time Approximation ◽  
Donor And Acceptor ◽  
Temperature Dependences ◽  
Neutral Impurity ◽  
P Type

AbstractTo determine donor and acceptor concentrations affecting electrical properties in ZnO crystals, the relaxation time approximation (RTA) has been used to analyze mobility and carrier concentration data measured from 80 to 400 K. Five scattering mechanisms are included: polar-optical-phonon, piezoelectric potential, deformation potential, ionized impurity, and neutral impurity scattering. Temperature dependences of intrinsic mobilities and Hall r factors are determined. Neutral impurity (ni) scattering can play an important role in limiting the total mobility in ZnO single crystals. By including ni scattering, the experimental deformation potential E1 = 3.8 eV for ZnO can be used, rather than treating E1 as a fitting parameter. This approach yields “intrinsic” mobilities for n-type and p-type ZnO, and other II-VI materials. At 300 K, the intrinsic electron Hall mobility in ZnO is predicted to be 230 cm2/Vs. The results of fitting the temperature dependences of mobility and carrier concentrations from representative ZnO and CdSe bulk samples are shown. Intrinsic results for n-type CdS and ZnS will also be discussed. The 300-K intrinsic hole Hall mobility in ZnO is predicted to be about 50 cm2/Vs.

High Field Electron Drift in a-Si:H

1993 ◽  
Vol 297 ◽  
Author(s):  
Qing Gu ◽  
Eric A. Schiff ◽  
Jean Baptiste Chevrier ◽  
Bernard Equer
Keyword(s):  
Electric Fields ◽  
High Field ◽  
Drift Mobility ◽  
Time Range ◽  
Electron Drift ◽  
Parameter Change ◽  
Transient Photocurrent ◽  
Field Mobility ◽  
High Electric Fields ◽  
Electron Drift Mobility

We have measured the electron drift mobility in a-Si:H at high electric fields (E ≤ 3.6 x 105 V%cm). The a-Si:Hpin structure was prepared at Palaiseau, and incorporated a thickp+ layer to retard high field breakdown. The drift mobility was obtained from transient photocurrent measurements from 1 ns - 1 ms following a laser pulse. Mobility increases as large as a factor of 30 were observed; at 77 K the high field mobility de¬pended exponentially upon field (exp(E/Eu), where E u= 1.1 x 105 V%cm). The same field dependence was observed in the time range 10 ns – 1 μs, indicating that the dispersion parameter change with field was negligible. This latter result appears to exclude hopping in the exponential conduction bandtail as the fundamental transport mechanism in a-Si:H above 77 K; alternate models are briefly discussed.

Ionized Impurity Scattering in Degenerate Many-Valley Semiconductors

1964 ◽  
Vol 135 (3A) ◽  
pp. A779-A784 ◽  
Author(s):  
John E. Robinson ◽  
Sergio Rodriguez
Keyword(s):  
Impurity Scattering ◽  
Ionized Impurity Scattering
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