The Schottky barrier of Co on strained and unstrained SixGe1-x alloys

Ja Hum Ku, Robert Nemanich

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

In this study, metal films of Co were deposited in situ on strained and unstrained SixGe1-x alloys, and the Schottky barrier (EF - EV) was determined by angle resolved ultraviolet photoemission spectroscopy (ARUPS). Measurements were obtained as a function of Ge composition. Strained and unstrained epitaxial SixGe1-x r alloys were grown on Si(100) waters using electron beam evaporation in an ultra-high vacuum molecular beam epitaxy (UHV MBE) chamber. The ARUPS experiments were performed to measure the Schottky barrier heights of Co on a series of SixGe1-x alloys, and to observe the surface states. The surface states of clean SixGe1-x alloys were observed and were extinguished as Co thickness increased to ∼ 0.4 Å. The p-type Schottky barrier of Co on Si was found to be 0.52 eV. The measured barrier heights of Co on strained SixGe1-x alloys ranged from 0.33 eV to 0.46 eV as x increased from 0.40 to 0.80. The Schottky barrier of Co on unstrained SixGe1-x alloys ranged from 0.23 eV to 0.41 eV as x increased from 0 to 0.60. In fact, the p-type Schottky barrier was essentially identical for strained and unstrained SixGe1-x alloys of the same concentration. This indicates that the n-type Schottky barrier is substantially different for strained and unstrained alloys. ARUPS was also conducted to measure the electron affinities of the series of SixGe1-x alloys and the work function of Co. The results show that the barrier does not follow the work function model.

Original languageEnglish (US)
Pages (from-to)262-266
Number of pages5
JournalApplied Surface Science
Volume104-105
DOIs
StatePublished - Sep 1996
Externally publishedYes

Fingerprint

Photoelectron spectroscopy
Ultraviolet spectroscopy
photoelectric emission
Surface states
spectroscopy
Electron affinity
Ultrahigh vacuum
electron affinity
metal films
Molecular beam epitaxy
ultrahigh vacuum
Electron beams
Evaporation
molecular beam epitaxy
chambers
Metals
evaporation
electron beams
Water
Chemical analysis

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Condensed Matter Physics

Cite this

The Schottky barrier of Co on strained and unstrained SixGe1-x alloys. / Ku, Ja Hum; Nemanich, Robert.

In: Applied Surface Science, Vol. 104-105, 09.1996, p. 262-266.

Research output: Contribution to journalArticle

@article{3f3ea6a45d6a4854877e224f4e0294ab,
title = "The Schottky barrier of Co on strained and unstrained SixGe1-x alloys",
abstract = "In this study, metal films of Co were deposited in situ on strained and unstrained SixGe1-x alloys, and the Schottky barrier (EF - EV) was determined by angle resolved ultraviolet photoemission spectroscopy (ARUPS). Measurements were obtained as a function of Ge composition. Strained and unstrained epitaxial SixGe1-x r alloys were grown on Si(100) waters using electron beam evaporation in an ultra-high vacuum molecular beam epitaxy (UHV MBE) chamber. The ARUPS experiments were performed to measure the Schottky barrier heights of Co on a series of SixGe1-x alloys, and to observe the surface states. The surface states of clean SixGe1-x alloys were observed and were extinguished as Co thickness increased to ∼ 0.4 {\AA}. The p-type Schottky barrier of Co on Si was found to be 0.52 eV. The measured barrier heights of Co on strained SixGe1-x alloys ranged from 0.33 eV to 0.46 eV as x increased from 0.40 to 0.80. The Schottky barrier of Co on unstrained SixGe1-x alloys ranged from 0.23 eV to 0.41 eV as x increased from 0 to 0.60. In fact, the p-type Schottky barrier was essentially identical for strained and unstrained SixGe1-x alloys of the same concentration. This indicates that the n-type Schottky barrier is substantially different for strained and unstrained alloys. ARUPS was also conducted to measure the electron affinities of the series of SixGe1-x alloys and the work function of Co. The results show that the barrier does not follow the work function model.",
author = "Ku, {Ja Hum} and Robert Nemanich",
year = "1996",
month = "9",
doi = "10.1016/S0169-4332(96)00155-9",
language = "English (US)",
volume = "104-105",
pages = "262--266",
journal = "Applied Surface Science",
issn = "0169-4332",
publisher = "Elsevier",

}

TY - JOUR

T1 - The Schottky barrier of Co on strained and unstrained SixGe1-x alloys

AU - Ku, Ja Hum

AU - Nemanich, Robert

PY - 1996/9

Y1 - 1996/9

N2 - In this study, metal films of Co were deposited in situ on strained and unstrained SixGe1-x alloys, and the Schottky barrier (EF - EV) was determined by angle resolved ultraviolet photoemission spectroscopy (ARUPS). Measurements were obtained as a function of Ge composition. Strained and unstrained epitaxial SixGe1-x r alloys were grown on Si(100) waters using electron beam evaporation in an ultra-high vacuum molecular beam epitaxy (UHV MBE) chamber. The ARUPS experiments were performed to measure the Schottky barrier heights of Co on a series of SixGe1-x alloys, and to observe the surface states. The surface states of clean SixGe1-x alloys were observed and were extinguished as Co thickness increased to ∼ 0.4 Å. The p-type Schottky barrier of Co on Si was found to be 0.52 eV. The measured barrier heights of Co on strained SixGe1-x alloys ranged from 0.33 eV to 0.46 eV as x increased from 0.40 to 0.80. The Schottky barrier of Co on unstrained SixGe1-x alloys ranged from 0.23 eV to 0.41 eV as x increased from 0 to 0.60. In fact, the p-type Schottky barrier was essentially identical for strained and unstrained SixGe1-x alloys of the same concentration. This indicates that the n-type Schottky barrier is substantially different for strained and unstrained alloys. ARUPS was also conducted to measure the electron affinities of the series of SixGe1-x alloys and the work function of Co. The results show that the barrier does not follow the work function model.

AB - In this study, metal films of Co were deposited in situ on strained and unstrained SixGe1-x alloys, and the Schottky barrier (EF - EV) was determined by angle resolved ultraviolet photoemission spectroscopy (ARUPS). Measurements were obtained as a function of Ge composition. Strained and unstrained epitaxial SixGe1-x r alloys were grown on Si(100) waters using electron beam evaporation in an ultra-high vacuum molecular beam epitaxy (UHV MBE) chamber. The ARUPS experiments were performed to measure the Schottky barrier heights of Co on a series of SixGe1-x alloys, and to observe the surface states. The surface states of clean SixGe1-x alloys were observed and were extinguished as Co thickness increased to ∼ 0.4 Å. The p-type Schottky barrier of Co on Si was found to be 0.52 eV. The measured barrier heights of Co on strained SixGe1-x alloys ranged from 0.33 eV to 0.46 eV as x increased from 0.40 to 0.80. The Schottky barrier of Co on unstrained SixGe1-x alloys ranged from 0.23 eV to 0.41 eV as x increased from 0 to 0.60. In fact, the p-type Schottky barrier was essentially identical for strained and unstrained SixGe1-x alloys of the same concentration. This indicates that the n-type Schottky barrier is substantially different for strained and unstrained alloys. ARUPS was also conducted to measure the electron affinities of the series of SixGe1-x alloys and the work function of Co. The results show that the barrier does not follow the work function model.

UR - http://www.scopus.com/inward/record.url?scp=18344401026&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=18344401026&partnerID=8YFLogxK

U2 - 10.1016/S0169-4332(96)00155-9

DO - 10.1016/S0169-4332(96)00155-9

M3 - Article

AN - SCOPUS:18344401026

VL - 104-105

SP - 262

EP - 266

JO - Applied Surface Science

JF - Applied Surface Science

SN - 0169-4332

ER -