Surface residue island nucleation in anhydrous HF/alcohol vapor processing of Si surfaces

Richard J. Carter, John R. Hauser, Robert Nemanich

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Anhydrous HF/methanol vapor-phase chemistries were employed to etch SiO2/Si surfaces at low pressure (5-50 Torr) and ambient temperature. The oxides on Si were formed from the following: (i) RCA chemical cleaning and (ii) UV-ozone treatment. Atomic force microscopy (AFM) and lateral force microscopy (LFM) were used to analyze the HF vapor-cleaned Si surfaces. AFM/LFM displayed residue islands distributed randomly upon the Si surface as a result of vapor-phase cleaning. As a result of etching RCA chemical oxides, the average lateral dimension of the residue islands is 40 nm and the average height of the islands is 6 nm. As a result of etching UV-ozone oxides, the average lateral dimension of the residue islands is 30 nm, and the average height of the islands is 3.5 nm. A decrease in residue island density is observed after the removal of a UV-ozone oxide compared to RCA chemical oxide removal. Secondary ion mass spectroscopy was used to characterize chemical impurities (O, C, F, and N) in the SiO2 films and and the Si surface after HF vapor-phase cleaning. The constituents of the residue islands have been attributed to nitrogen impurities and silicon atoms imbedded in the passivating oxides. Results indicate that condensation of methanol vapor onto the bare Si surface, after oxide removal, is necessary for residue island formation. We suggest a model in which residue island nucleation occurs from nonvolatile N-Si complexes that form hydrogen bonds with methanol molecules and diffuse into the adsorbed alcohol layer. The molecular impurities then interact and form residue islands.

Original languageEnglish (US)
Pages (from-to)3512-3518
Number of pages7
JournalJournal of the Electrochemical Society
Volume147
Issue number9
DOIs
StatePublished - Sep 2000
Externally publishedYes

Fingerprint

Oxides
alcohols
Alcohols
Nucleation
Vapors
nucleation
vapors
Processing
Ozone
oxides
Methanol
Impurities
ozone
Etching
Cleaning
Atomic force microscopy
Microscopic examination
methyl alcohol
vapor phases
Chemical cleaning

ASJC Scopus subject areas

  • Electrochemistry
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

Cite this

Surface residue island nucleation in anhydrous HF/alcohol vapor processing of Si surfaces. / Carter, Richard J.; Hauser, John R.; Nemanich, Robert.

In: Journal of the Electrochemical Society, Vol. 147, No. 9, 09.2000, p. 3512-3518.

Research output: Contribution to journalArticle

@article{b3ddd6025d24410e8e74f68ef520f475,
title = "Surface residue island nucleation in anhydrous HF/alcohol vapor processing of Si surfaces",
abstract = "Anhydrous HF/methanol vapor-phase chemistries were employed to etch SiO2/Si surfaces at low pressure (5-50 Torr) and ambient temperature. The oxides on Si were formed from the following: (i) RCA chemical cleaning and (ii) UV-ozone treatment. Atomic force microscopy (AFM) and lateral force microscopy (LFM) were used to analyze the HF vapor-cleaned Si surfaces. AFM/LFM displayed residue islands distributed randomly upon the Si surface as a result of vapor-phase cleaning. As a result of etching RCA chemical oxides, the average lateral dimension of the residue islands is 40 nm and the average height of the islands is 6 nm. As a result of etching UV-ozone oxides, the average lateral dimension of the residue islands is 30 nm, and the average height of the islands is 3.5 nm. A decrease in residue island density is observed after the removal of a UV-ozone oxide compared to RCA chemical oxide removal. Secondary ion mass spectroscopy was used to characterize chemical impurities (O, C, F, and N) in the SiO2 films and and the Si surface after HF vapor-phase cleaning. The constituents of the residue islands have been attributed to nitrogen impurities and silicon atoms imbedded in the passivating oxides. Results indicate that condensation of methanol vapor onto the bare Si surface, after oxide removal, is necessary for residue island formation. We suggest a model in which residue island nucleation occurs from nonvolatile N-Si complexes that form hydrogen bonds with methanol molecules and diffuse into the adsorbed alcohol layer. The molecular impurities then interact and form residue islands.",
author = "Carter, {Richard J.} and Hauser, {John R.} and Robert Nemanich",
year = "2000",
month = "9",
doi = "10.1149/1.1393929",
language = "English (US)",
volume = "147",
pages = "3512--3518",
journal = "Journal of the Electrochemical Society",
issn = "0013-4651",
publisher = "Electrochemical Society, Inc.",
number = "9",

}

TY - JOUR

T1 - Surface residue island nucleation in anhydrous HF/alcohol vapor processing of Si surfaces

AU - Carter, Richard J.

AU - Hauser, John R.

AU - Nemanich, Robert

PY - 2000/9

Y1 - 2000/9

N2 - Anhydrous HF/methanol vapor-phase chemistries were employed to etch SiO2/Si surfaces at low pressure (5-50 Torr) and ambient temperature. The oxides on Si were formed from the following: (i) RCA chemical cleaning and (ii) UV-ozone treatment. Atomic force microscopy (AFM) and lateral force microscopy (LFM) were used to analyze the HF vapor-cleaned Si surfaces. AFM/LFM displayed residue islands distributed randomly upon the Si surface as a result of vapor-phase cleaning. As a result of etching RCA chemical oxides, the average lateral dimension of the residue islands is 40 nm and the average height of the islands is 6 nm. As a result of etching UV-ozone oxides, the average lateral dimension of the residue islands is 30 nm, and the average height of the islands is 3.5 nm. A decrease in residue island density is observed after the removal of a UV-ozone oxide compared to RCA chemical oxide removal. Secondary ion mass spectroscopy was used to characterize chemical impurities (O, C, F, and N) in the SiO2 films and and the Si surface after HF vapor-phase cleaning. The constituents of the residue islands have been attributed to nitrogen impurities and silicon atoms imbedded in the passivating oxides. Results indicate that condensation of methanol vapor onto the bare Si surface, after oxide removal, is necessary for residue island formation. We suggest a model in which residue island nucleation occurs from nonvolatile N-Si complexes that form hydrogen bonds with methanol molecules and diffuse into the adsorbed alcohol layer. The molecular impurities then interact and form residue islands.

AB - Anhydrous HF/methanol vapor-phase chemistries were employed to etch SiO2/Si surfaces at low pressure (5-50 Torr) and ambient temperature. The oxides on Si were formed from the following: (i) RCA chemical cleaning and (ii) UV-ozone treatment. Atomic force microscopy (AFM) and lateral force microscopy (LFM) were used to analyze the HF vapor-cleaned Si surfaces. AFM/LFM displayed residue islands distributed randomly upon the Si surface as a result of vapor-phase cleaning. As a result of etching RCA chemical oxides, the average lateral dimension of the residue islands is 40 nm and the average height of the islands is 6 nm. As a result of etching UV-ozone oxides, the average lateral dimension of the residue islands is 30 nm, and the average height of the islands is 3.5 nm. A decrease in residue island density is observed after the removal of a UV-ozone oxide compared to RCA chemical oxide removal. Secondary ion mass spectroscopy was used to characterize chemical impurities (O, C, F, and N) in the SiO2 films and and the Si surface after HF vapor-phase cleaning. The constituents of the residue islands have been attributed to nitrogen impurities and silicon atoms imbedded in the passivating oxides. Results indicate that condensation of methanol vapor onto the bare Si surface, after oxide removal, is necessary for residue island formation. We suggest a model in which residue island nucleation occurs from nonvolatile N-Si complexes that form hydrogen bonds with methanol molecules and diffuse into the adsorbed alcohol layer. The molecular impurities then interact and form residue islands.

UR - http://www.scopus.com/inward/record.url?scp=0034273871&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034273871&partnerID=8YFLogxK

U2 - 10.1149/1.1393929

DO - 10.1149/1.1393929

M3 - Article

AN - SCOPUS:0034273871

VL - 147

SP - 3512

EP - 3518

JO - Journal of the Electrochemical Society

JF - Journal of the Electrochemical Society

SN - 0013-4651

IS - 9

ER -