Valense band structure of Gex Si1-x for hole transport calculation

Ying Fu, Kaj Grahn, Magnus Willander

Research output: Contribution to journalArticleScientificpeer-review

24 Citations (Scopus)

Abstract

We have calculated the hole densities of states and the velocities as functions of energy in strained and relaxed p-type Ge/sub x/Si/sub 1/spl minus/x/ layers grown on /spl lang/001/spl rang/ Si substrates. It is shown that the nonparabolic and nonspherical effects are very large in the energy range of (0, 0.2 eV) measured from the heavy hole band edge. Deeper into the valence band, the bands gradually become parabolic and spherical. For most applications, the impurity doping concentration is below 10/sup 20/ cm/sup /spl minus/3/. For 10/sup 20/ cm/sup /spl minus/3/ p-type doped Si, the Fermi level is 77.3 meV at 77 K. It is therefore concluded that the nonparabolic and nonspherical effects must be taken into proper consideration when investigating the transport properties of p-type Ge/sub x/Si/sub 1/spl minus/x/ samples. The calculated data of both relaxed and strained Ge/sub x/Si/sub 1/spl minus/x/ valence band structures are curve fitted and a data library is built up for further study of the hole transport properties. The mobility and the diffusion coefficient are largely affected when the doping concentration is increased. It is found that at high doping concentration the contributions from the light hole and spin split-off bands become very important, they can become even larger than the contribution from the heavy hole band, even if their densities of states are smaller than that of the heavy hole band.
Original languageEnglish
Pages (from-to)26-31
Number of pages6
JournalIEEE Transactions on Electron Devices
Volume41
Issue number1
DOIs
Publication statusPublished - 1994
MoE publication typeA1 Journal article-refereed

Fingerprint

Band structure
Doping (additives)
Valence bands
Transport properties
Fermi level
Impurities
Substrates

Cite this

Fu, Ying ; Grahn, Kaj ; Willander, Magnus. / Valense band structure of Gex Si1-x for hole transport calculation. In: IEEE Transactions on Electron Devices. 1994 ; Vol. 41, No. 1. pp. 26-31.
@article{bccbf35a68e949ebbdf6ed437b608917,
title = "Valense band structure of Gex Si1-x for hole transport calculation",
abstract = "We have calculated the hole densities of states and the velocities as functions of energy in strained and relaxed p-type Ge/sub x/Si/sub 1/spl minus/x/ layers grown on /spl lang/001/spl rang/ Si substrates. It is shown that the nonparabolic and nonspherical effects are very large in the energy range of (0, 0.2 eV) measured from the heavy hole band edge. Deeper into the valence band, the bands gradually become parabolic and spherical. For most applications, the impurity doping concentration is below 10/sup 20/ cm/sup /spl minus/3/. For 10/sup 20/ cm/sup /spl minus/3/ p-type doped Si, the Fermi level is 77.3 meV at 77 K. It is therefore concluded that the nonparabolic and nonspherical effects must be taken into proper consideration when investigating the transport properties of p-type Ge/sub x/Si/sub 1/spl minus/x/ samples. The calculated data of both relaxed and strained Ge/sub x/Si/sub 1/spl minus/x/ valence band structures are curve fitted and a data library is built up for further study of the hole transport properties. The mobility and the diffusion coefficient are largely affected when the doping concentration is increased. It is found that at high doping concentration the contributions from the light hole and spin split-off bands become very important, they can become even larger than the contribution from the heavy hole band, even if their densities of states are smaller than that of the heavy hole band.",
author = "Ying Fu and Kaj Grahn and Magnus Willander",
year = "1994",
doi = "10.1109/16.259616",
language = "English",
volume = "41",
pages = "26--31",
journal = "IEEE Transactions on Electron Devices",
issn = "0018-9383",
publisher = "Institute of Electrical and Electronic Engineers IEEE",
number = "1",

}

Valense band structure of Gex Si1-x for hole transport calculation. / Fu, Ying; Grahn, Kaj; Willander, Magnus.

In: IEEE Transactions on Electron Devices, Vol. 41, No. 1, 1994, p. 26-31.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Valense band structure of Gex Si1-x for hole transport calculation

AU - Fu, Ying

AU - Grahn, Kaj

AU - Willander, Magnus

PY - 1994

Y1 - 1994

N2 - We have calculated the hole densities of states and the velocities as functions of energy in strained and relaxed p-type Ge/sub x/Si/sub 1/spl minus/x/ layers grown on /spl lang/001/spl rang/ Si substrates. It is shown that the nonparabolic and nonspherical effects are very large in the energy range of (0, 0.2 eV) measured from the heavy hole band edge. Deeper into the valence band, the bands gradually become parabolic and spherical. For most applications, the impurity doping concentration is below 10/sup 20/ cm/sup /spl minus/3/. For 10/sup 20/ cm/sup /spl minus/3/ p-type doped Si, the Fermi level is 77.3 meV at 77 K. It is therefore concluded that the nonparabolic and nonspherical effects must be taken into proper consideration when investigating the transport properties of p-type Ge/sub x/Si/sub 1/spl minus/x/ samples. The calculated data of both relaxed and strained Ge/sub x/Si/sub 1/spl minus/x/ valence band structures are curve fitted and a data library is built up for further study of the hole transport properties. The mobility and the diffusion coefficient are largely affected when the doping concentration is increased. It is found that at high doping concentration the contributions from the light hole and spin split-off bands become very important, they can become even larger than the contribution from the heavy hole band, even if their densities of states are smaller than that of the heavy hole band.

AB - We have calculated the hole densities of states and the velocities as functions of energy in strained and relaxed p-type Ge/sub x/Si/sub 1/spl minus/x/ layers grown on /spl lang/001/spl rang/ Si substrates. It is shown that the nonparabolic and nonspherical effects are very large in the energy range of (0, 0.2 eV) measured from the heavy hole band edge. Deeper into the valence band, the bands gradually become parabolic and spherical. For most applications, the impurity doping concentration is below 10/sup 20/ cm/sup /spl minus/3/. For 10/sup 20/ cm/sup /spl minus/3/ p-type doped Si, the Fermi level is 77.3 meV at 77 K. It is therefore concluded that the nonparabolic and nonspherical effects must be taken into proper consideration when investigating the transport properties of p-type Ge/sub x/Si/sub 1/spl minus/x/ samples. The calculated data of both relaxed and strained Ge/sub x/Si/sub 1/spl minus/x/ valence band structures are curve fitted and a data library is built up for further study of the hole transport properties. The mobility and the diffusion coefficient are largely affected when the doping concentration is increased. It is found that at high doping concentration the contributions from the light hole and spin split-off bands become very important, they can become even larger than the contribution from the heavy hole band, even if their densities of states are smaller than that of the heavy hole band.

U2 - 10.1109/16.259616

DO - 10.1109/16.259616

M3 - Article

VL - 41

SP - 26

EP - 31

JO - IEEE Transactions on Electron Devices

JF - IEEE Transactions on Electron Devices

SN - 0018-9383

IS - 1

ER -