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Title: Isotropic plasma etching of Ge Si and SiN x films

Abstract

This study reports on selective isotropic dry etching of chemically vapor deposited (CVD) Ge thin film, release layers using a Shibaura chemical downstream etcher (CDE) with NF 3 and Ar based plasma chemistry. Relative etch rates between Ge, Si and SiN x are described with etch rate reductions achieved by adjusting plasma chemistry with O 2. Formation of oxides reducing etch rates were measured for both Ge and Si, but nitrides or oxy-nitrides created using direct injection of NO into the process chamber were measured to increase Si and SiN x etch rates while retarding Ge etching.

Authors:
 [1];  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1323884
Report Number(s):
SAND-2016-4884J
Journal ID: ISSN 2166-2746; 640682; TRN: US1700144
Grant/Contract Number:
AC04-94AL85000
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Vacuum Science and Technology. B, Nanotechnology and Microelectronics
Additional Journal Information:
Journal Volume: 34; Journal Issue: 5; Journal ID: ISSN 2166-2746
Publisher:
American Vacuum Society/AIP
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Germanium; Plasma etching; Silicon

Citation Formats

Henry, Michael David, and Douglas, Erica Ann. Isotropic plasma etching of Ge Si and SiNx films. United States: N. p., 2016. Web. doi:10.1116/1.4961944.
Henry, Michael David, & Douglas, Erica Ann. Isotropic plasma etching of Ge Si and SiNx films. United States. doi:10.1116/1.4961944.
Henry, Michael David, and Douglas, Erica Ann. Wed . "Isotropic plasma etching of Ge Si and SiNx films". United States. doi:10.1116/1.4961944. https://www.osti.gov/servlets/purl/1323884.
@article{osti_1323884,
title = {Isotropic plasma etching of Ge Si and SiNx films},
author = {Henry, Michael David and Douglas, Erica Ann},
abstractNote = {This study reports on selective isotropic dry etching of chemically vapor deposited (CVD) Ge thin film, release layers using a Shibaura chemical downstream etcher (CDE) with NF3 and Ar based plasma chemistry. Relative etch rates between Ge, Si and SiNx are described with etch rate reductions achieved by adjusting plasma chemistry with O2. Formation of oxides reducing etch rates were measured for both Ge and Si, but nitrides or oxy-nitrides created using direct injection of NO into the process chamber were measured to increase Si and SiNx etch rates while retarding Ge etching.},
doi = {10.1116/1.4961944},
journal = {Journal of Vacuum Science and Technology. B, Nanotechnology and Microelectronics},
number = 5,
volume = 34,
place = {United States},
year = {Wed Aug 31 00:00:00 EDT 2016},
month = {Wed Aug 31 00:00:00 EDT 2016}
}

Journal Article:
Free Publicly Available Full Text
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  • In this article, we report the experimental realization of SiGe/Si materials using CF{sub 4}/Ar and Cl{sub 2}/Ar mixed-gas inductively coupled plasma (ICP) etching process. The effects of process parameters such as gas combination and gas species on etch rates and selectivities were investigated. It was found that samples in CF{sub 4} gas result in a faster etching rate than those obtained in Cl{sub 2} gas, which are responsible for a lower boiling point for Si-based fluoride. The lower boiling point provides more chemically active Si and SiGe materials. Moreover, the selectivity of 1.5 between Si{sub 0.3}Ge{sub 0.7}/Si by ICP technologymore » was found and higher than that obtained previously by reactive ion etching reported in the literature. Based on these etch characteristics, the application of the ICP process to the device fabrication of SiGe doped-channel field-effect transistors was conducted. The devices using ICP mesa have excellent pinch-off characteristics with relatively low leakage current, small output conduction in the saturated region, and low knee voltage.« less
  • The addition of germane and dopant gases significantly alter the growth kinetics of low temperature Si epitaxy. Germane, phosphine, and diborane have been reported to both enhance and retard film growth rate in various processes. The growth kinetics of remote plasma enhanced chemical vapor deposition are largely unaffected by the addition of GeH{sub 4} or by in situ doping. Adsorption sites are created by low energy ion bombardment and are only minimally dependent on temperature for activation. Ion-induced gas phase reactions also play an important role in the deposition via formation of precursors which have greater sticking probabilities and insertionmore » rates into the hydrogenated surface than for the direct reactions of SiH{sub 4} and GeH{sub 4} with the Si surface in thermal chemical vapor deposition. 17 refs., 4 figs.« less
  • Minority-carrier response and conductance loss characteristics of SiN{sub x}/Si/Ge/n-GaAs(001) metal{endash}insulator{endash}semiconductor (MIS) structures are presented. The response time of minority carriers with Si({le}10{Angstrom})/Ge (20 {Angstrom}) interlayers, as determined by the capacitance{endash}voltage (C{endash}V) method, is several orders of magnitude smaller than those with Si interlayers only. The minority carriers in {ital n}-type Si/Ge/GaAs layers respond to even a small ac signal of 1 kHz at room temperature, which is ascribed to the smaller band gap and thus a higher intrinsic carrier concentration of Ge. The minority carriers in the SiN{sub x}/Si/Ge/n-GaAs MIS structures respond to a 1 MHz signal at a samplemore » temperature of 230{degree}C. Temperature-dependent C{endash}V measurements on the GaAs MIS structure with Si/Ge, interlayers revealed the activation energy (E{sub a}) of the minority-carrier recombination to be about 0.58 eV. The conductance loss characteristics of SiN{sub x}/Si/Ge/GaAs structures indicate a contribution by interface traps responding to slow states, while the fast states are a result of interface defects of the SiN{sub x}/Si/GaAs MIS system. {copyright} {ital 1997 American Institute of Physics.}« less
  • The dislocation density in AlGaN epitaxial layers with Al content as high as 45% grown on sapphire substrates has been effectively reduced by introducing an in-situ deposited SiN{sub x} nanomask layer in this study. By closely monitoring the evolution of numerous material properties, such as surface morphology, dislocation density, photoluminescence, strain states, and electron mobility of the Si-Al{sub 0.45}Ga{sub 0.55}N layers as the functions of SiN{sub x} interlayer growth time, the surface coverage fraction of SiN{sub x} is found to be a crucial factor determining the strain states and dislocation density. The dependence of the strain states and the dislocationmore » density on the surface coverage fraction of SiN{sub x} nanomask supports the very different growth models of Al-rich AlGaN on SiN{sub x} interlayer due to the reduced nucleation selectivity compared with the GaN counterpart. Compared with GaN, which can only nucleate at open pores of SiN{sub x} nanomask, Al-rich AlGaN can simultaneously nucleate at both open pores and SiN{sub x} covered areas. Dislocations will annihilate at the openings due to the 3D growth initiated on the opening area, while 2D growth mode is preserved on SiN{sub x} and the threading dislocations are also preserved. During the following growth process, lateral overgrowth will proceed from the Al{sub 0.45}Ga{sub 0.55}N islands on the openings towards the regions covered by SiN{sub x}, relaxing the compressive strain and bending the dislocations at the same time.« less
  • Using magnetron cosputtering of SiO{sub 2}, Ge, and Si targets, Si-based SiO{sub 2}:Ge:Si films were fabricated for exploring the influence of Si target proportion (P{sub Si}) and annealing temperature (Ta) on formation, local structure, and phonon properties of nanocrystalline Si{sub 1-x}Ge{sub x} (nc-Si{sub 1-x}Ge{sub x}). At low P{sub Si} and Ta higher than 800 deg. C, no nc-Si{sub 1-x}Ge{sub x} but a kind of composite nanocrystal consisting of a Ge core, GeSi shell, and amorphous Si outer shell is formed in the SiO{sub 2} matrix. At moderate P{sub Si}, nc-Si{sub 1-x}Ge{sub x} begins to be formed at Ta=800 deg. Cmore » and coexists with nc-Ge at Ta=1100 deg. C. At high P{sub Si}, it was disclosed that both optical phonon frequency and lattice spacing of nc-Si{sub 1-x}Ge{sub x} increase with raising Ta. The possible origin of this phenomenon is discussed by considering three factors, the phonon confinement, strain effect, and composition variation of nc-Si{sub 1-x}Ge{sub x}. This work will be helpful in understanding the growth process of ternary GeSiO films and beneficial to further investigations on optical properties of nc-Ge{sub 1-x}Si{sub x} in the ternary matrix.« less