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Thermodynamics of amorphous SiN(O)H dielectric films synthesized by plasma‐enhanced chemical vapor deposition
Author(s) -
Chen Jiewei,
Niu Min,
Calvin Jason,
Asplund Megan,
King Sean W.,
Woodfield Brian F.,
Navrotsky Alexandra
Publication year - 2018
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15350
Subject(s) - amorphous solid , gibbs free energy , chemical vapor deposition , standard enthalpy of formation , dielectric , plasma enhanced chemical vapor deposition , chemical stability , enthalpy , chemistry , materials science , thermodynamics , crystallography , organic chemistry , physics , optoelectronics
Abstract Thin films of amorphous Si NH (a‐Si NH ) and amorphous Si NOH (a‐Si NOH ) synthesized by plasma‐enhanced chemical vapor deposition ( PECVD ) are used extensively in the semiconductor industry, but little is known regarding their thermodynamic stability, and there are several long‐term reliability issues for these materials. To address the stability issues, a detailed thermodynamic investigation has been conducted on a series of a‐Si NH , and a‐Si NOH dielectric films. High‐temperature oxidative drop‐solution calorimetry in molten sodium molybdate solvent at 1075 K was utilized to determine the formation enthalpies from the elements and from crystalline counterparts/gaseous products. Together with entropy data derived from cryogenic heat capacity measurements, we confirmed that the incorporation of more hydrogen and oxygen leads to more negative enthalpies and Gibbs free energies of formation from elements. Coupled with FTIR structural analysis, the thermochemical data suggest that the Si–H 2 chain structure and Si–O–Si bonding configurations provide the system with extra thermodynamic stability. However, the Gibbs free energies of formation from crystalline constituents and gaseous products are either positive or nearly zero, indicating that these amorphous films are not stable against decomposition, which may cause problems in high‐temperature applications.