| 1. |
|
|
| 2. |
- Bellotti, E., et al.
(författare)
-
Monte Carlo calculation of hole initiated impact ionization in 4H phase SiC
- 2000
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 87:8, s. 3864-3871
-
Tidskriftsartikel (refereegranskat)abstract
- In this article, we present a comprehensive, full band theoretical study of the high field, hole transport properties of the 4H phase of silicon carbide (4H-SiC). The calculations are performed using a full band ensemble Monte Carlo simulation that includes numerically tabulated impact ionization rates, and phonon and ionized impurity scattering rates. In addition, the simulation includes a mechanism, interband tunneling, by which the holes can move between bands in the proximity of band intersection points, It is found that there exists a significant anisotropy in the calculated steady-state hole drift velocity for fields applied parallel and perpendicular to the c-axis direction. Good agreement with experimental measurements of the hole initiated impact ionization coefficient for fields applied along the c axis is obtained, provided that interband tunneling in the proximity of band intersections is included in the model. If interband tunneling is not included, the calculated ionization coefficients are orders of magnitude lower than the experimental measurements. © 2000 American Institute of Physics.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Brennan, K.F., et al.
(författare)
-
Monte Carlo modeling of wurtzite and 4H phase semiconductor materials
- 2001
-
Ingår i: VLSI design (Print). - 1065-514X .- 1563-5171. - 0852617046 ; 13:1-4, s. 117-124
-
Tidskriftsartikel (refereegranskat)abstract
- We present a discussion of the complexities encountered in particle simulation models for noncubic symmetry materials, focusing on the wurtzite and 4H phases of semiconductors. We have identified three general issues, band structure, scattering mechanisms, and band intersections, which in our opinion, constitute the most important modifications to Monte Carlo simulators for cubic symmetry materials. Owing to the increased number of atoms and size of the unit cell, the band structure is far more complex in wurtzite and 4H polytypes than in zincblende phase semiconductors. This added complexity is reflected by the greater number of bands, smaller Brillouin zone and concomitant increase in the number of band intersections. We have found that the band intersection points greatly influence the transport dynamics. In this paper, we discuss our initial attempts at treating transport near these points
|
|
| 6. |
- Brennan, K.F., et al.
(författare)
-
Monte Carlo simulation of noncubic symmetry semiconducting materials and devices
- 2000
-
Ingår i: IEEE Transactions on Electron Devices. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9383. ; 47:10, s. 1882-1890
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we discuss the complexities that arise in Monte Carlo based modeling of noncubic symmetry semiconductors and their related devices. We have identified three general issues, band structure, scattering mechanisms, and band intersections that require some modification of the Monte Carlo simulator from that for cubic symmetry. Owing to the increased size and number of atoms per unit cell, the band structure is far more complex in noncubic than in zincblende phase semiconductors. This added complexity is reflected by the greater number of bands, smaller Brillouin zone and concomitant increase in the number of band intersections. We present strategies for modeling the effects of band intersections on the carrier dynamics using the Monte Carlo method. It is found that the band intersection points greatly affect the carrier transport, most dramatically in the determination of the impact ionization and breakdown properties of devices and bulk material. Excellent agreement with experimental measurements of the impact ionization coefficients is obtained only when treatment of the band intersections is included within the model.
|
|
| 7. |
- Ruden, P.P., et al.
(författare)
-
Modeling of Band-to-band tunneling transitions during drift in Monte Carlo transport simulations
- 2000
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 88:3, s. 1488-1493
-
Tidskriftsartikel (refereegranskat)abstract
- The conventional method of semiconductor charge carrier transport investigations using full band ensemble Monte Carlo simulations is extended to allow for tunneling between bands during accelerated drift of the carriers. The essentially classical picture of transport, as simulated, is preserved by implementing a stochastic selection of the band index of the initial state of each scattering process associated with phonons, with impurities, or with impact ionization. Relative probabilities for the band assignment are calculated from the overlap integrals of the cell-periodic parts of Bloch wave functions belonging to different bands, for k-vectors along the carrier k-space trajectory between successive scattering events. As an example, the method is applied to Monte Carlo transport simulations for holes in 4H SiC in a homogeneous applied electric field. Tunneling between valence bands during the drift phases is shown to have a significant impact on the carrier energy distributions when large electric fields are applied, and on physical parameters that directly depend on the carrier energy, such as the hole initiated impact ionization coefficient.
|
|
