Mechanism for chemical‐vapor deposition of tungsten on silicon from tungsten hexafluoride

ABSTRACTSelective area depositon of adherent tungsten (W) film on titanium (Ti)—ion—irradiated silicon dioxide (SiOz) is achieved. First, Ti—ion irradiation through a stencil mask is performed at 600 eV for 1.1 X 1016 atoms/cm2 in a reaction chamber. Next, ArF excimer laser (λ = 193 nm) chemical vapor deposition (CVD) with tungsten hexafluoride (WFs) and hydrogen (H2) is carried out for 40 seconds at 400 K. Finally, low—pressure (LP) CVD is carried out at 600 K and then W films are deposited selectively on the ion—irradiated SiO2 Without the laser CVD step, the ion—irradiation pattern disappears during LPCVD and no W film deposition occurs. Therefore, laser CVD is essential in our experiments.

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Nucleation on SiO2 during the Selective Chemical Vapor Deposition of Tungsten by the Hydrogen Reduction of Tungsten Hexafluoride

Journal of The Electrochemical Society ◽

10.1149/1.2059366 ◽

1994 ◽

Vol 141 (12) ◽

pp. 3532-3539 ◽

Cited By ~ 9

Author(s):

Nathan Desatnik ◽

Brian E. Thompson

Keyword(s):

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Hydrogen Reduction ◽

Chemical Vapor ◽

Tungsten Hexafluoride ◽

Selective Chemical

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Characterization of Tungsten Nucleation Layers Deposited Using Various Sih4 and Wf6 Flows

MRS Proceedings ◽

10.1557/proc-337-569 ◽

1994 ◽

Vol 337 ◽

Author(s):

V.V.S. Rana ◽

M. Eizenberg ◽

S. Ghanayem ◽

J. Roberts ◽

A.K. Sinha

Keyword(s):

Chemical Vapor Deposition ◽

Bulk Density ◽

Deposition Rate ◽

Incubation Time ◽

Vapor Deposition ◽

Chemical Vapor ◽

Pure Tungsten ◽

Tungsten Hexafluoride ◽

Step Coverage

ABSTRACTChemical vapor deposition (CVD) of tungsten nucleation films is typically done using silane (SiH4) reduction of tungsten hexafluoride (WF6). For SiH4/WF6 flow ratios of ≤ 1, pure tungsten of bulk density and resistivity is deposited. Upon increasing the ratio to 2, nearly 40 at.% Si is incorporated in tungsten films. At a ratio of 3, hexagonal WSi2 is deposited, and at ratios of > 6 WSi2 along with silicon is deposited. A maximum in deposition rate is obtained for WSi2 at the ratio of 3, and the deposition rate drops as more silicon is being deposited. The step coverage of films drops dramatically as one moves away from pure W films. The deposition of these films takes place without any incubation time.

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Low Pressure Chemical Vapor Deposition of Tungsten and Aluminum for VLSI Applications

MRS Proceedings ◽

10.1557/proc-71-229 ◽

1986 ◽

Vol 71 ◽

Cited By ~ 2

Author(s):

R. A. Levy ◽

M. L. Green

Keyword(s):

Surface Roughness ◽

Optical Properties ◽

Chemical Vapor Deposition ◽

Leakage Current ◽

Vapor Deposition ◽

Chemical Vapor ◽

Current Status ◽

Tungsten Hexafluoride ◽

Excess Surface ◽

Pressure Chemical

AbstractThis paper reviews the current status of LPCVD tungsten and aluminum for VLSI applications. Using deposition chemistries based on tungsten hexafluoride and tri-isobutyl aluminum, W and Al deposits are characterized with respect to their electrical, mechanical, structural, chemical and optical properties. Although results of this study prove these two LPCVD processes to be compatible with current VLSI fabrication, certain problems must still be resolved for complete commercial acceptance. These problems include, in the case of selective LPCVD tungsten, the occurrence of leakage current across N+/P-Tub junctions, and in the case of LPCVD aluminum, the relatively poor electromigration resistance (compared to Al-Cu) and excess surface roughness.

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Proximity Effect in the Low Pressure Chemical Vapor Deposition of Tungsten.

MRS Proceedings ◽

10.1557/proc-131-623 ◽

1988 ◽

Vol 131 ◽

Author(s):

N. Lifshitz

Keyword(s):

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Chemical Vapor ◽

Low Pressure ◽

Blocking Agent ◽

The Self ◽

Tungsten Hexafluoride ◽

Pressure Chemical ◽

Tungsten Surface ◽

Selection Of

ABSTRACTThe self-limiting effect during Low Pressure Chemical Vapor Deposition of tungsten is manifested by a sudden interruption of the reduction of tungsten hexafluoride WF6 by silicon, so that only very thin (self-limited) films of silicon-reduced tungsten can be grown. It has been shown that the self-limiting effect is caused by formation of the non-volatile subfluoride WF4. The temperature dependence of the self-limiting thickness of the tungsten films grown in a hot-wall reactor exhibits a characteristic maximum at temperatures near 350°C, which indicates that at this temperature the rate of formation of WF4 is lower than at temperatures above and below. In the present paper we attempt to explain this peculiar dependence. We suggest a mechanism responsible for formation of the blocking agent WF4. We demonstrate that the presence of a hot tungsten surface is essential for the strong self-limiting effect. This leads us to the discussion of the proper selection of the reactor type (hot-wall vs. cold-wall) for different process requirements.

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In situ study of electron beam-induced chemical vapor deposition of Au in an environmental TEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100137653 ◽

1995 ◽

Vol 53 ◽

pp. 256-257

Author(s):

J. Drucker ◽

R. Sharma ◽

J. Kouvetakis ◽

K.H.J. Weiss

Keyword(s):

Electron Beam ◽

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Quantum Effect ◽

Line Drawing ◽

Chemical Vapor ◽

Environmental Cell ◽

Engineering Changes ◽

Kinetics Of

Patterning of metals is a key element in the fabrication of integrated microelectronics. For circuit repair and engineering changes constructive lithography, writing techniques, based on electron, ion or photon beam-induced decomposition of precursor molecule and its deposition on top of a structure have gained wide acceptance Recently, scanning probe techniques have been used for line drawing and wire growth of W on a silicon substrate for quantum effect devices. The kinetics of electron beam induced W deposition from WF6 gas has been studied by adsorbing the gas on SiO2 surface and measuring the growth in a TEM for various exposure times. Our environmental cell allows us to control not only electron exposure time but also the gas pressure flow and the temperature. We have studied the growth kinetics of Au Chemical vapor deposition (CVD), in situ, at different temperatures with/without the electron beam on highly clean Si surfaces in an environmental cell fitted inside a TEM column.

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The relaxation of compressive biaxial strains in SOS via microtwins

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100155013 ◽

1989 ◽

Vol 47 ◽

pp. 608-609

Author(s):

M. E. Twigg ◽

E. D. Richmond ◽

J. G. Pellegrino

Keyword(s):

Thin Film ◽

Chemical Vapor Deposition ◽

Molecular Beam Epitaxy ◽

Compressive Stress ◽

Vapor Deposition ◽

Partial Dislocation ◽

Molecular Beam ◽

Volume Fraction ◽

Chemical Vapor ◽

Silicon Thin Film

For heteroepitaxial systems, such as silicon on sapphire (SOS), microtwins occur in significant numbers and are thought to contribute to strain relief in the silicon thin film. The size of this contribution can be assessed from TEM measurements, of the differential volume fraction of microtwins, dV/dν (the derivative of the microtwin volume V with respect to the film volume ν), for SOS grown by both chemical vapor deposition (CVD) and molecular beam epitaxy (MBE).In a (001) silicon thin film subjected to compressive stress along the [100] axis , this stress can be relieved by four twinning systems: a/6[211]/( lll), a/6(21l]/(l1l), a/6[21l] /( l1l), and a/6(2ll)/(1ll).3 For the a/6[211]/(1ll) system, the glide of a single a/6[2ll] twinning partial dislocation draws the two halves of the crystal, separated by the microtwin, closer together by a/3.

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